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1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package android.support.v4.app;
18 
19 import android.app.Activity;
20 import android.content.ComponentCallbacks;
21 import android.content.Context;
22 import android.content.Intent;
23 import android.content.IntentSender;
24 import android.content.res.Configuration;
25 import android.content.res.Resources;
26 import android.os.Bundle;
27 import android.os.Parcel;
28 import android.os.Parcelable;
29 import android.support.annotation.CallSuper;
30 import android.support.annotation.NonNull;
31 import android.support.annotation.Nullable;
32 import android.support.annotation.StringRes;
33 import android.support.v4.util.DebugUtils;
34 import android.support.v4.util.SimpleArrayMap;
35 import android.support.v4.view.LayoutInflaterCompat;
36 import android.util.AttributeSet;
37 import android.util.Log;
38 import android.util.SparseArray;
39 import android.view.ContextMenu;
40 import android.view.ContextMenu.ContextMenuInfo;
41 import android.view.LayoutInflater;
42 import android.view.Menu;
43 import android.view.MenuInflater;
44 import android.view.MenuItem;
45 import android.view.View;
46 import android.view.View.OnCreateContextMenuListener;
47 import android.view.ViewGroup;
48 import android.view.animation.Animation;
49 import android.widget.AdapterView;
50 
51 import java.io.FileDescriptor;
52 import java.io.PrintWriter;
53 
54 final class FragmentState implements Parcelable {
55     final String mClassName;
56     final int mIndex;
57     final boolean mFromLayout;
58     final int mFragmentId;
59     final int mContainerId;
60     final String mTag;
61     final boolean mRetainInstance;
62     final boolean mDetached;
63     final Bundle mArguments;
64     final boolean mHidden;
65 
66     Bundle mSavedFragmentState;
67 
68     Fragment mInstance;
69 
FragmentState(Fragment frag)70     public FragmentState(Fragment frag) {
71         mClassName = frag.getClass().getName();
72         mIndex = frag.mIndex;
73         mFromLayout = frag.mFromLayout;
74         mFragmentId = frag.mFragmentId;
75         mContainerId = frag.mContainerId;
76         mTag = frag.mTag;
77         mRetainInstance = frag.mRetainInstance;
78         mDetached = frag.mDetached;
79         mArguments = frag.mArguments;
80         mHidden = frag.mHidden;
81     }
82 
FragmentState(Parcel in)83     public FragmentState(Parcel in) {
84         mClassName = in.readString();
85         mIndex = in.readInt();
86         mFromLayout = in.readInt() != 0;
87         mFragmentId = in.readInt();
88         mContainerId = in.readInt();
89         mTag = in.readString();
90         mRetainInstance = in.readInt() != 0;
91         mDetached = in.readInt() != 0;
92         mArguments = in.readBundle();
93         mHidden = in.readInt() != 0;
94         mSavedFragmentState = in.readBundle();
95     }
96 
instantiate(FragmentHostCallback host, Fragment parent, FragmentManagerNonConfig childNonConfig)97     public Fragment instantiate(FragmentHostCallback host, Fragment parent,
98             FragmentManagerNonConfig childNonConfig) {
99         if (mInstance == null) {
100             final Context context = host.getContext();
101             if (mArguments != null) {
102                 mArguments.setClassLoader(context.getClassLoader());
103             }
104 
105             mInstance = Fragment.instantiate(context, mClassName, mArguments);
106 
107             if (mSavedFragmentState != null) {
108                 mSavedFragmentState.setClassLoader(context.getClassLoader());
109                 mInstance.mSavedFragmentState = mSavedFragmentState;
110             }
111             mInstance.setIndex(mIndex, parent);
112             mInstance.mFromLayout = mFromLayout;
113             mInstance.mRestored = true;
114             mInstance.mFragmentId = mFragmentId;
115             mInstance.mContainerId = mContainerId;
116             mInstance.mTag = mTag;
117             mInstance.mRetainInstance = mRetainInstance;
118             mInstance.mDetached = mDetached;
119             mInstance.mHidden = mHidden;
120             mInstance.mFragmentManager = host.mFragmentManager;
121 
122             if (FragmentManagerImpl.DEBUG) Log.v(FragmentManagerImpl.TAG,
123                     "Instantiated fragment " + mInstance);
124         }
125         mInstance.mChildNonConfig = childNonConfig;
126         return mInstance;
127     }
128 
129     @Override
describeContents()130     public int describeContents() {
131         return 0;
132     }
133 
134     @Override
writeToParcel(Parcel dest, int flags)135     public void writeToParcel(Parcel dest, int flags) {
136         dest.writeString(mClassName);
137         dest.writeInt(mIndex);
138         dest.writeInt(mFromLayout ? 1 : 0);
139         dest.writeInt(mFragmentId);
140         dest.writeInt(mContainerId);
141         dest.writeString(mTag);
142         dest.writeInt(mRetainInstance ? 1 : 0);
143         dest.writeInt(mDetached ? 1 : 0);
144         dest.writeBundle(mArguments);
145         dest.writeInt(mHidden? 1 : 0);
146         dest.writeBundle(mSavedFragmentState);
147     }
148 
149     public static final Parcelable.Creator<FragmentState> CREATOR
150             = new Parcelable.Creator<FragmentState>() {
151         @Override
152         public FragmentState createFromParcel(Parcel in) {
153             return new FragmentState(in);
154         }
155 
156         @Override
157         public FragmentState[] newArray(int size) {
158             return new FragmentState[size];
159         }
160     };
161 }
162 
163 /**
164  * Static library support version of the framework's {@link android.app.Fragment}.
165  * Used to write apps that run on platforms prior to Android 3.0.  When running
166  * on Android 3.0 or above, this implementation is still used; it does not try
167  * to switch to the framework's implementation. See the framework {@link android.app.Fragment}
168  * documentation for a class overview.
169  *
170  * <p>The main differences when using this support version instead of the framework version are:
171  * <ul>
172  *  <li>Your activity must extend {@link FragmentActivity}
173  *  <li>You must call {@link FragmentActivity#getSupportFragmentManager} to get the
174  *  {@link FragmentManager}
175  * </ul>
176  *
177  */
178 public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener {
179     private static final SimpleArrayMap<String, Class<?>> sClassMap =
180             new SimpleArrayMap<String, Class<?>>();
181 
182     static final Object USE_DEFAULT_TRANSITION = new Object();
183 
184     static final int INITIALIZING = 0;     // Not yet created.
185     static final int CREATED = 1;          // Created.
186     static final int ACTIVITY_CREATED = 2; // The activity has finished its creation.
187     static final int STOPPED = 3;          // Fully created, not started.
188     static final int STARTED = 4;          // Created and started, not resumed.
189     static final int RESUMED = 5;          // Created started and resumed.
190 
191     int mState = INITIALIZING;
192 
193     // Non-null if the fragment's view hierarchy is currently animating away,
194     // meaning we need to wait a bit on completely destroying it.  This is the
195     // view that is animating.
196     View mAnimatingAway;
197 
198     // If mAnimatingAway != null, this is the state we should move to once the
199     // animation is done.
200     int mStateAfterAnimating;
201 
202     // When instantiated from saved state, this is the saved state.
203     Bundle mSavedFragmentState;
204     SparseArray<Parcelable> mSavedViewState;
205 
206     // Index into active fragment array.
207     int mIndex = -1;
208 
209     // Internal unique name for this fragment;
210     String mWho;
211 
212     // Construction arguments;
213     Bundle mArguments;
214 
215     // Target fragment.
216     Fragment mTarget;
217 
218     // For use when retaining a fragment: this is the index of the last mTarget.
219     int mTargetIndex = -1;
220 
221     // Target request code.
222     int mTargetRequestCode;
223 
224     // True if the fragment is in the list of added fragments.
225     boolean mAdded;
226 
227     // If set this fragment is being removed from its activity.
228     boolean mRemoving;
229 
230     // Set to true if this fragment was instantiated from a layout file.
231     boolean mFromLayout;
232 
233     // Set to true when the view has actually been inflated in its layout.
234     boolean mInLayout;
235 
236     // True if this fragment has been restored from previously saved state.
237     boolean mRestored;
238 
239     // Number of active back stack entries this fragment is in.
240     int mBackStackNesting;
241 
242     // The fragment manager we are associated with.  Set as soon as the
243     // fragment is used in a transaction; cleared after it has been removed
244     // from all transactions.
245     FragmentManagerImpl mFragmentManager;
246 
247     // Host this fragment is attached to.
248     FragmentHostCallback mHost;
249 
250     // Private fragment manager for child fragments inside of this one.
251     FragmentManagerImpl mChildFragmentManager;
252 
253     // For use when restoring fragment state and descendant fragments are retained.
254     // This state is set by FragmentState.instantiate and cleared in onCreate.
255     FragmentManagerNonConfig mChildNonConfig;
256 
257     // If this Fragment is contained in another Fragment, this is that container.
258     Fragment mParentFragment;
259 
260     // The optional identifier for this fragment -- either the container ID if it
261     // was dynamically added to the view hierarchy, or the ID supplied in
262     // layout.
263     int mFragmentId;
264 
265     // When a fragment is being dynamically added to the view hierarchy, this
266     // is the identifier of the parent container it is being added to.
267     int mContainerId;
268 
269     // The optional named tag for this fragment -- usually used to find
270     // fragments that are not part of the layout.
271     String mTag;
272 
273     // Set to true when the app has requested that this fragment be hidden
274     // from the user.
275     boolean mHidden;
276 
277     // Set to true when the app has requested that this fragment be deactivated.
278     boolean mDetached;
279 
280     // If set this fragment would like its instance retained across
281     // configuration changes.
282     boolean mRetainInstance;
283 
284     // If set this fragment is being retained across the current config change.
285     boolean mRetaining;
286 
287     // If set this fragment has menu items to contribute.
288     boolean mHasMenu;
289 
290     // Set to true to allow the fragment's menu to be shown.
291     boolean mMenuVisible = true;
292 
293     // Used to verify that subclasses call through to super class.
294     boolean mCalled;
295 
296     // If app has requested a specific animation, this is the one to use.
297     int mNextAnim;
298 
299     // The parent container of the fragment after dynamically added to UI.
300     ViewGroup mContainer;
301 
302     // The View generated for this fragment.
303     View mView;
304 
305     // The real inner view that will save/restore state.
306     View mInnerView;
307 
308     // Whether this fragment should defer starting until after other fragments
309     // have been started and their loaders are finished.
310     boolean mDeferStart;
311 
312     // Hint provided by the app that this fragment is currently visible to the user.
313     boolean mUserVisibleHint = true;
314 
315     LoaderManagerImpl mLoaderManager;
316     boolean mLoadersStarted;
317     boolean mCheckedForLoaderManager;
318 
319     Object mEnterTransition = null;
320     Object mReturnTransition = USE_DEFAULT_TRANSITION;
321     Object mExitTransition = null;
322     Object mReenterTransition = USE_DEFAULT_TRANSITION;
323     Object mSharedElementEnterTransition = null;
324     Object mSharedElementReturnTransition = USE_DEFAULT_TRANSITION;
325     Boolean mAllowReturnTransitionOverlap;
326     Boolean mAllowEnterTransitionOverlap;
327 
328     SharedElementCallback mEnterTransitionCallback = null;
329     SharedElementCallback mExitTransitionCallback = null;
330 
331     /**
332      * State information that has been retrieved from a fragment instance
333      * through {@link FragmentManager#saveFragmentInstanceState(Fragment)
334      * FragmentManager.saveFragmentInstanceState}.
335      */
336     public static class SavedState implements Parcelable {
337         final Bundle mState;
338 
SavedState(Bundle state)339         SavedState(Bundle state) {
340             mState = state;
341         }
342 
SavedState(Parcel in, ClassLoader loader)343         SavedState(Parcel in, ClassLoader loader) {
344             mState = in.readBundle();
345             if (loader != null && mState != null) {
346                 mState.setClassLoader(loader);
347             }
348         }
349 
350         @Override
describeContents()351         public int describeContents() {
352             return 0;
353         }
354 
355         @Override
writeToParcel(Parcel dest, int flags)356         public void writeToParcel(Parcel dest, int flags) {
357             dest.writeBundle(mState);
358         }
359 
360         public static final Parcelable.Creator<SavedState> CREATOR
361                 = new Parcelable.Creator<SavedState>() {
362             @Override
363             public SavedState createFromParcel(Parcel in) {
364                 return new SavedState(in, null);
365             }
366 
367             @Override
368             public SavedState[] newArray(int size) {
369                 return new SavedState[size];
370             }
371         };
372     }
373 
374     /**
375      * Thrown by {@link Fragment#instantiate(Context, String, Bundle)} when
376      * there is an instantiation failure.
377      */
378     static public class InstantiationException extends RuntimeException {
InstantiationException(String msg, Exception cause)379         public InstantiationException(String msg, Exception cause) {
380             super(msg, cause);
381         }
382     }
383 
384     /**
385      * Default constructor.  <strong>Every</strong> fragment must have an
386      * empty constructor, so it can be instantiated when restoring its
387      * activity's state.  It is strongly recommended that subclasses do not
388      * have other constructors with parameters, since these constructors
389      * will not be called when the fragment is re-instantiated; instead,
390      * arguments can be supplied by the caller with {@link #setArguments}
391      * and later retrieved by the Fragment with {@link #getArguments}.
392      *
393      * <p>Applications should generally not implement a constructor. Prefer
394      * {@link #onAttach(Context)} instead. It is the first place application code can run where
395      * the fragment is ready to be used - the point where the fragment is actually associated with
396      * its context. Some applications may also want to implement {@link #onInflate} to retrieve
397      * attributes from a layout resource, although note this happens when the fragment is attached.
398      */
Fragment()399     public Fragment() {
400     }
401 
402     /**
403      * Like {@link #instantiate(Context, String, Bundle)} but with a null
404      * argument Bundle.
405      */
instantiate(Context context, String fname)406     public static Fragment instantiate(Context context, String fname) {
407         return instantiate(context, fname, null);
408     }
409 
410     /**
411      * Create a new instance of a Fragment with the given class name.  This is
412      * the same as calling its empty constructor.
413      *
414      * @param context The calling context being used to instantiate the fragment.
415      * This is currently just used to get its ClassLoader.
416      * @param fname The class name of the fragment to instantiate.
417      * @param args Bundle of arguments to supply to the fragment, which it
418      * can retrieve with {@link #getArguments()}.  May be null.
419      * @return Returns a new fragment instance.
420      * @throws InstantiationException If there is a failure in instantiating
421      * the given fragment class.  This is a runtime exception; it is not
422      * normally expected to happen.
423      */
instantiate(Context context, String fname, @Nullable Bundle args)424     public static Fragment instantiate(Context context, String fname, @Nullable Bundle args) {
425         try {
426             Class<?> clazz = sClassMap.get(fname);
427             if (clazz == null) {
428                 // Class not found in the cache, see if it's real, and try to add it
429                 clazz = context.getClassLoader().loadClass(fname);
430                 sClassMap.put(fname, clazz);
431             }
432             Fragment f = (Fragment)clazz.newInstance();
433             if (args != null) {
434                 args.setClassLoader(f.getClass().getClassLoader());
435                 f.mArguments = args;
436             }
437             return f;
438         } catch (ClassNotFoundException e) {
439             throw new InstantiationException("Unable to instantiate fragment " + fname
440                     + ": make sure class name exists, is public, and has an"
441                     + " empty constructor that is public", e);
442         } catch (java.lang.InstantiationException e) {
443             throw new InstantiationException("Unable to instantiate fragment " + fname
444                     + ": make sure class name exists, is public, and has an"
445                     + " empty constructor that is public", e);
446         } catch (IllegalAccessException e) {
447             throw new InstantiationException("Unable to instantiate fragment " + fname
448                     + ": make sure class name exists, is public, and has an"
449                     + " empty constructor that is public", e);
450         }
451     }
452 
453     /**
454      * Determine if the given fragment name is a support library fragment class.
455      *
456      * @param context Context used to determine the correct ClassLoader to use
457      * @param fname Class name of the fragment to test
458      * @return true if <code>fname</code> is <code>android.support.v4.app.Fragment</code>
459      *         or a subclass, false otherwise.
460      */
isSupportFragmentClass(Context context, String fname)461     static boolean isSupportFragmentClass(Context context, String fname) {
462         try {
463             Class<?> clazz = sClassMap.get(fname);
464             if (clazz == null) {
465                 // Class not found in the cache, see if it's real, and try to add it
466                 clazz = context.getClassLoader().loadClass(fname);
467                 sClassMap.put(fname, clazz);
468             }
469             return Fragment.class.isAssignableFrom(clazz);
470         } catch (ClassNotFoundException e) {
471             return false;
472         }
473     }
474 
restoreViewState(Bundle savedInstanceState)475     final void restoreViewState(Bundle savedInstanceState) {
476         if (mSavedViewState != null) {
477             mInnerView.restoreHierarchyState(mSavedViewState);
478             mSavedViewState = null;
479         }
480         mCalled = false;
481         onViewStateRestored(savedInstanceState);
482         if (!mCalled) {
483             throw new SuperNotCalledException("Fragment " + this
484                     + " did not call through to super.onViewStateRestored()");
485         }
486     }
487 
setIndex(int index, Fragment parent)488     final void setIndex(int index, Fragment parent) {
489         mIndex = index;
490         if (parent != null) {
491             mWho = parent.mWho + ":" + mIndex;
492         } else {
493             mWho = "android:fragment:" + mIndex;
494         }
495     }
496 
isInBackStack()497     final boolean isInBackStack() {
498         return mBackStackNesting > 0;
499     }
500 
501     /**
502      * Subclasses can not override equals().
503      */
equals(Object o)504     @Override final public boolean equals(Object o) {
505         return super.equals(o);
506     }
507 
508     /**
509      * Subclasses can not override hashCode().
510      */
hashCode()511     @Override final public int hashCode() {
512         return super.hashCode();
513     }
514 
515     @Override
toString()516     public String toString() {
517         StringBuilder sb = new StringBuilder(128);
518         DebugUtils.buildShortClassTag(this, sb);
519         if (mIndex >= 0) {
520             sb.append(" #");
521             sb.append(mIndex);
522         }
523         if (mFragmentId != 0) {
524             sb.append(" id=0x");
525             sb.append(Integer.toHexString(mFragmentId));
526         }
527         if (mTag != null) {
528             sb.append(" ");
529             sb.append(mTag);
530         }
531         sb.append('}');
532         return sb.toString();
533     }
534 
535     /**
536      * Return the identifier this fragment is known by.  This is either
537      * the android:id value supplied in a layout or the container view ID
538      * supplied when adding the fragment.
539      */
getId()540     final public int getId() {
541         return mFragmentId;
542     }
543 
544     /**
545      * Get the tag name of the fragment, if specified.
546      */
getTag()547     final public String getTag() {
548         return mTag;
549     }
550 
551     /**
552      * Supply the construction arguments for this fragment.  This can only
553      * be called before the fragment has been attached to its activity; that
554      * is, you should call it immediately after constructing the fragment.  The
555      * arguments supplied here will be retained across fragment destroy and
556      * creation.
557      */
setArguments(Bundle args)558     public void setArguments(Bundle args) {
559         if (mIndex >= 0) {
560             throw new IllegalStateException("Fragment already active");
561         }
562         mArguments = args;
563     }
564 
565     /**
566      * Return the arguments supplied when the fragment was instantiated,
567      * if any.
568      */
getArguments()569     final public Bundle getArguments() {
570         return mArguments;
571     }
572 
573     /**
574      * Set the initial saved state that this Fragment should restore itself
575      * from when first being constructed, as returned by
576      * {@link FragmentManager#saveFragmentInstanceState(Fragment)
577      * FragmentManager.saveFragmentInstanceState}.
578      *
579      * @param state The state the fragment should be restored from.
580      */
setInitialSavedState(SavedState state)581     public void setInitialSavedState(SavedState state) {
582         if (mIndex >= 0) {
583             throw new IllegalStateException("Fragment already active");
584         }
585         mSavedFragmentState = state != null && state.mState != null
586                 ? state.mState : null;
587     }
588 
589     /**
590      * Optional target for this fragment.  This may be used, for example,
591      * if this fragment is being started by another, and when done wants to
592      * give a result back to the first.  The target set here is retained
593      * across instances via {@link FragmentManager#putFragment
594      * FragmentManager.putFragment()}.
595      *
596      * @param fragment The fragment that is the target of this one.
597      * @param requestCode Optional request code, for convenience if you
598      * are going to call back with {@link #onActivityResult(int, int, Intent)}.
599      */
setTargetFragment(Fragment fragment, int requestCode)600     public void setTargetFragment(Fragment fragment, int requestCode) {
601         mTarget = fragment;
602         mTargetRequestCode = requestCode;
603     }
604 
605     /**
606      * Return the target fragment set by {@link #setTargetFragment}.
607      */
getTargetFragment()608     final public Fragment getTargetFragment() {
609         return mTarget;
610     }
611 
612     /**
613      * Return the target request code set by {@link #setTargetFragment}.
614      */
getTargetRequestCode()615     final public int getTargetRequestCode() {
616         return mTargetRequestCode;
617     }
618 
619     /**
620      * Return the {@link Context} this fragment is currently associated with.
621      */
getContext()622     public Context getContext() {
623         return mHost == null ? null : mHost.getContext();
624     }
625 
626     /**
627      * Return the {@link FragmentActivity} this fragment is currently associated with.
628      * May return {@code null} if the fragment is associated with a {@link Context}
629      * instead.
630      */
getActivity()631     final public FragmentActivity getActivity() {
632         return mHost == null ? null : (FragmentActivity) mHost.getActivity();
633     }
634 
635     /**
636      * Return the host object of this fragment. May return {@code null} if the fragment
637      * isn't currently being hosted.
638      */
getHost()639     final public Object getHost() {
640         return mHost == null ? null : mHost.onGetHost();
641     }
642 
643     /**
644      * Return <code>getActivity().getResources()</code>.
645      */
getResources()646     final public Resources getResources() {
647         if (mHost == null) {
648             throw new IllegalStateException("Fragment " + this + " not attached to Activity");
649         }
650         return mHost.getContext().getResources();
651     }
652 
653     /**
654      * Return a localized, styled CharSequence from the application's package's
655      * default string table.
656      *
657      * @param resId Resource id for the CharSequence text
658      */
getText(@tringRes int resId)659     public final CharSequence getText(@StringRes int resId) {
660         return getResources().getText(resId);
661     }
662 
663     /**
664      * Return a localized string from the application's package's
665      * default string table.
666      *
667      * @param resId Resource id for the string
668      */
getString(@tringRes int resId)669     public final String getString(@StringRes int resId) {
670         return getResources().getString(resId);
671     }
672 
673     /**
674      * Return a localized formatted string from the application's package's
675      * default string table, substituting the format arguments as defined in
676      * {@link java.util.Formatter} and {@link java.lang.String#format}.
677      *
678      * @param resId Resource id for the format string
679      * @param formatArgs The format arguments that will be used for substitution.
680      */
681 
getString(@tringRes int resId, Object... formatArgs)682     public final String getString(@StringRes int resId, Object... formatArgs) {
683         return getResources().getString(resId, formatArgs);
684     }
685 
686     /**
687      * Return the FragmentManager for interacting with fragments associated
688      * with this fragment's activity.  Note that this will be non-null slightly
689      * before {@link #getActivity()}, during the time from when the fragment is
690      * placed in a {@link FragmentTransaction} until it is committed and
691      * attached to its activity.
692      *
693      * <p>If this Fragment is a child of another Fragment, the FragmentManager
694      * returned here will be the parent's {@link #getChildFragmentManager()}.
695      */
getFragmentManager()696     final public FragmentManager getFragmentManager() {
697         return mFragmentManager;
698     }
699 
700     /**
701      * Return a private FragmentManager for placing and managing Fragments
702      * inside of this Fragment.
703      */
getChildFragmentManager()704     final public FragmentManager getChildFragmentManager() {
705         if (mChildFragmentManager == null) {
706             instantiateChildFragmentManager();
707             if (mState >= RESUMED) {
708                 mChildFragmentManager.dispatchResume();
709             } else if (mState >= STARTED) {
710                 mChildFragmentManager.dispatchStart();
711             } else if (mState >= ACTIVITY_CREATED) {
712                 mChildFragmentManager.dispatchActivityCreated();
713             } else if (mState >= CREATED) {
714                 mChildFragmentManager.dispatchCreate();
715             }
716         }
717         return mChildFragmentManager;
718     }
719 
720     /**
721      * Returns the parent Fragment containing this Fragment.  If this Fragment
722      * is attached directly to an Activity, returns null.
723      */
getParentFragment()724     final public Fragment getParentFragment() {
725         return mParentFragment;
726     }
727 
728     /**
729      * Return true if the fragment is currently added to its activity.
730      */
isAdded()731     final public boolean isAdded() {
732         return mHost != null && mAdded;
733     }
734 
735     /**
736      * Return true if the fragment has been explicitly detached from the UI.
737      * That is, {@link FragmentTransaction#detach(Fragment)
738      * FragmentTransaction.detach(Fragment)} has been used on it.
739      */
isDetached()740     final public boolean isDetached() {
741         return mDetached;
742     }
743 
744     /**
745      * Return true if this fragment is currently being removed from its
746      * activity.  This is  <em>not</em> whether its activity is finishing, but
747      * rather whether it is in the process of being removed from its activity.
748      */
isRemoving()749     final public boolean isRemoving() {
750         return mRemoving;
751     }
752 
753     /**
754      * Return true if the layout is included as part of an activity view
755      * hierarchy via the &lt;fragment&gt; tag.  This will always be true when
756      * fragments are created through the &lt;fragment&gt; tag, <em>except</em>
757      * in the case where an old fragment is restored from a previous state and
758      * it does not appear in the layout of the current state.
759      */
isInLayout()760     final public boolean isInLayout() {
761         return mInLayout;
762     }
763 
764     /**
765      * Return true if the fragment is in the resumed state.  This is true
766      * for the duration of {@link #onResume()} and {@link #onPause()} as well.
767      */
isResumed()768     final public boolean isResumed() {
769         return mState >= RESUMED;
770     }
771 
772     /**
773      * Return true if the fragment is currently visible to the user.  This means
774      * it: (1) has been added, (2) has its view attached to the window, and
775      * (3) is not hidden.
776      */
isVisible()777     final public boolean isVisible() {
778         return isAdded() && !isHidden() && mView != null
779                 && mView.getWindowToken() != null && mView.getVisibility() == View.VISIBLE;
780     }
781 
782     /**
783      * Return true if the fragment has been hidden.  By default fragments
784      * are shown.  You can find out about changes to this state with
785      * {@link #onHiddenChanged}.  Note that the hidden state is orthogonal
786      * to other states -- that is, to be visible to the user, a fragment
787      * must be both started and not hidden.
788      */
isHidden()789     final public boolean isHidden() {
790         return mHidden;
791     }
792 
793     /** @hide */
hasOptionsMenu()794     final public boolean hasOptionsMenu() {
795         return mHasMenu;
796     }
797 
798     /** @hide */
isMenuVisible()799     final public boolean isMenuVisible() {
800         return mMenuVisible;
801     }
802 
803     /**
804      * Called when the hidden state (as returned by {@link #isHidden()} of
805      * the fragment has changed.  Fragments start out not hidden; this will
806      * be called whenever the fragment changes state from that.
807      * @param hidden True if the fragment is now hidden, false otherwise.
808      */
onHiddenChanged(boolean hidden)809     public void onHiddenChanged(boolean hidden) {
810     }
811 
812     /**
813      * Control whether a fragment instance is retained across Activity
814      * re-creation (such as from a configuration change).  This can only
815      * be used with fragments not in the back stack.  If set, the fragment
816      * lifecycle will be slightly different when an activity is recreated:
817      * <ul>
818      * <li> {@link #onDestroy()} will not be called (but {@link #onDetach()} still
819      * will be, because the fragment is being detached from its current activity).
820      * <li> {@link #onCreate(Bundle)} will not be called since the fragment
821      * is not being re-created.
822      * <li> {@link #onAttach(Activity)} and {@link #onActivityCreated(Bundle)} <b>will</b>
823      * still be called.
824      * </ul>
825      */
setRetainInstance(boolean retain)826     public void setRetainInstance(boolean retain) {
827         mRetainInstance = retain;
828     }
829 
getRetainInstance()830     final public boolean getRetainInstance() {
831         return mRetainInstance;
832     }
833 
834     /**
835      * Report that this fragment would like to participate in populating
836      * the options menu by receiving a call to {@link #onCreateOptionsMenu}
837      * and related methods.
838      *
839      * @param hasMenu If true, the fragment has menu items to contribute.
840      */
setHasOptionsMenu(boolean hasMenu)841     public void setHasOptionsMenu(boolean hasMenu) {
842         if (mHasMenu != hasMenu) {
843             mHasMenu = hasMenu;
844             if (isAdded() && !isHidden()) {
845                 mHost.onSupportInvalidateOptionsMenu();
846             }
847         }
848     }
849 
850     /**
851      * Set a hint for whether this fragment's menu should be visible.  This
852      * is useful if you know that a fragment has been placed in your view
853      * hierarchy so that the user can not currently seen it, so any menu items
854      * it has should also not be shown.
855      *
856      * @param menuVisible The default is true, meaning the fragment's menu will
857      * be shown as usual.  If false, the user will not see the menu.
858      */
setMenuVisibility(boolean menuVisible)859     public void setMenuVisibility(boolean menuVisible) {
860         if (mMenuVisible != menuVisible) {
861             mMenuVisible = menuVisible;
862             if (mHasMenu && isAdded() && !isHidden()) {
863                 mHost.onSupportInvalidateOptionsMenu();
864             }
865         }
866     }
867 
868     /**
869      * Set a hint to the system about whether this fragment's UI is currently visible
870      * to the user. This hint defaults to true and is persistent across fragment instance
871      * state save and restore.
872      *
873      * <p>An app may set this to false to indicate that the fragment's UI is
874      * scrolled out of visibility or is otherwise not directly visible to the user.
875      * This may be used by the system to prioritize operations such as fragment lifecycle updates
876      * or loader ordering behavior.</p>
877      *
878      * <p><strong>Note:</strong> This method may be called outside of the fragment lifecycle.
879      * and thus has no ordering guarantees with regard to fragment lifecycle method calls.</p>
880      *
881      * @param isVisibleToUser true if this fragment's UI is currently visible to the user (default),
882      *                        false if it is not.
883      */
setUserVisibleHint(boolean isVisibleToUser)884     public void setUserVisibleHint(boolean isVisibleToUser) {
885         if (!mUserVisibleHint && isVisibleToUser && mState < STARTED
886                 && mFragmentManager != null && isAdded()) {
887             mFragmentManager.performPendingDeferredStart(this);
888         }
889         mUserVisibleHint = isVisibleToUser;
890         mDeferStart = mState < STARTED && !isVisibleToUser;
891     }
892 
893     /**
894      * @return The current value of the user-visible hint on this fragment.
895      * @see #setUserVisibleHint(boolean)
896      */
897     public boolean getUserVisibleHint() {
898         return mUserVisibleHint;
899     }
900 
901     /**
902      * Return the LoaderManager for this fragment, creating it if needed.
903      */
904     public LoaderManager getLoaderManager() {
905         if (mLoaderManager != null) {
906             return mLoaderManager;
907         }
908         if (mHost == null) {
909             throw new IllegalStateException("Fragment " + this + " not attached to Activity");
910         }
911         mCheckedForLoaderManager = true;
912         mLoaderManager = mHost.getLoaderManager(mWho, mLoadersStarted, true);
913         return mLoaderManager;
914     }
915 
916     /**
917      * Call {@link Activity#startActivity(Intent)} from the fragment's
918      * containing Activity.
919      */
920     public void startActivity(Intent intent) {
921         startActivity(intent, null);
922     }
923 
924     /**
925      * Call {@link Activity#startActivity(Intent, Bundle)} from the fragment's
926      * containing Activity.
927      */
928     public void startActivity(Intent intent, @Nullable Bundle options) {
929         if (mHost == null) {
930             throw new IllegalStateException("Fragment " + this + " not attached to Activity");
931         }
932         mHost.onStartActivityFromFragment(this /*fragment*/, intent, -1, options);
933     }
934 
935     /**
936      * Call {@link Activity#startActivityForResult(Intent, int)} from the fragment's
937      * containing Activity.
938      */
939     public void startActivityForResult(Intent intent, int requestCode) {
940         startActivityForResult(intent, requestCode, null);
941     }
942 
943     /**
944      * Call {@link Activity#startActivityForResult(Intent, int, Bundle)} from the fragment's
945      * containing Activity.
946      */
947     public void startActivityForResult(Intent intent, int requestCode, @Nullable Bundle options) {
948         if (mHost == null) {
949             throw new IllegalStateException("Fragment " + this + " not attached to Activity");
950         }
951         mHost.onStartActivityFromFragment(this /*fragment*/, intent, requestCode, options);
952     }
953 
954     /**
955      * Call {@link Activity#startIntentSenderForResult(IntentSender, int, Intent, int, int, int,
956      * Bundle)} from the fragment's containing Activity.
957      */
958     public void startIntentSenderForResult(IntentSender intent, int requestCode,
959             @Nullable Intent fillInIntent, int flagsMask, int flagsValues, int extraFlags,
960             Bundle options) throws IntentSender.SendIntentException {
961         if (mHost == null) {
962             throw new IllegalStateException("Fragment " + this + " not attached to Activity");
963         }
964         mHost.onStartIntentSenderFromFragment(this, intent, requestCode, fillInIntent, flagsMask,
965                 flagsValues, extraFlags, options);
966     }
967 
968     /**
969      * Receive the result from a previous call to
970      * {@link #startActivityForResult(Intent, int)}.  This follows the
971      * related Activity API as described there in
972      * {@link Activity#onActivityResult(int, int, Intent)}.
973      *
974      * @param requestCode The integer request code originally supplied to
975      *                    startActivityForResult(), allowing you to identify who this
976      *                    result came from.
977      * @param resultCode The integer result code returned by the child activity
978      *                   through its setResult().
979      * @param data An Intent, which can return result data to the caller
980      *               (various data can be attached to Intent "extras").
981      */
982     public void onActivityResult(int requestCode, int resultCode, Intent data) {
983     }
984 
985     /**
986      * Requests permissions to be granted to this application. These permissions
987      * must be requested in your manifest, they should not be granted to your app,
988      * and they should have protection level {@link android.content.pm.PermissionInfo
989      * #PROTECTION_DANGEROUS dangerous}, regardless whether they are declared by
990      * the platform or a third-party app.
991      * <p>
992      * Normal permissions {@link android.content.pm.PermissionInfo#PROTECTION_NORMAL}
993      * are granted at install time if requested in the manifest. Signature permissions
994      * {@link android.content.pm.PermissionInfo#PROTECTION_SIGNATURE} are granted at
995      * install time if requested in the manifest and the signature of your app matches
996      * the signature of the app declaring the permissions.
997      * </p>
998      * <p>
999      * If your app does not have the requested permissions the user will be presented
1000      * with UI for accepting them. After the user has accepted or rejected the
1001      * requested permissions you will receive a callback on {@link
1002      * #onRequestPermissionsResult(int, String[], int[])} reporting whether the
1003      * permissions were granted or not.
1004      * </p>
1005      * <p>
1006      * Note that requesting a permission does not guarantee it will be granted and
1007      * your app should be able to run without having this permission.
1008      * </p>
1009      * <p>
1010      * This method may start an activity allowing the user to choose which permissions
1011      * to grant and which to reject. Hence, you should be prepared that your activity
1012      * may be paused and resumed. Further, granting some permissions may require
1013      * a restart of you application. In such a case, the system will recreate the
1014      * activity stack before delivering the result to {@link
1015      * #onRequestPermissionsResult(int, String[], int[])}.
1016      * </p>
1017      * <p>
1018      * When checking whether you have a permission you should use {@link
1019      * android.content.Context#checkSelfPermission(String)}.
1020      * </p>
1021      * <p>
1022      * Calling this API for permissions already granted to your app would show UI
1023      * to the user to decided whether the app can still hold these permissions. This
1024      * can be useful if the way your app uses the data guarded by the permissions
1025      * changes significantly.
1026      * </p>
1027      * <p>
1028      * A sample permissions request looks like this:
1029      * </p>
1030      * <code><pre><p>
1031      * private void showContacts() {
1032      *     if (getActivity().checkSelfPermission(Manifest.permission.READ_CONTACTS)
1033      *             != PackageManager.PERMISSION_GRANTED) {
1034      *         requestPermissions(new String[]{Manifest.permission.READ_CONTACTS},
1035      *                 PERMISSIONS_REQUEST_READ_CONTACTS);
1036      *     } else {
1037      *         doShowContacts();
1038      *     }
1039      * }
1040      *
1041      * {@literal @}Override
1042      * public void onRequestPermissionsResult(int requestCode, String[] permissions,
1043      *         int[] grantResults) {
1044      *     if (requestCode == PERMISSIONS_REQUEST_READ_CONTACTS
1045      *             && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
1046      *         doShowContacts();
1047      *     }
1048      * }
1049      * </code></pre></p>
1050      *
1051      * @param permissions The requested permissions.
1052      * @param requestCode Application specific request code to match with a result
1053      *    reported to {@link #onRequestPermissionsResult(int, String[], int[])}.
1054      *
1055      * @see #onRequestPermissionsResult(int, String[], int[])
1056      * @see android.content.Context#checkSelfPermission(String)
1057      */
1058     public final void requestPermissions(@NonNull String[] permissions, int requestCode) {
1059         if (mHost == null) {
1060             throw new IllegalStateException("Fragment " + this + " not attached to Activity");
1061         }
1062         mHost.onRequestPermissionsFromFragment(this, permissions, requestCode);
1063     }
1064 
1065     /**
1066      * Callback for the result from requesting permissions. This method
1067      * is invoked for every call on {@link #requestPermissions(String[], int)}.
1068      * <p>
1069      * <strong>Note:</strong> It is possible that the permissions request interaction
1070      * with the user is interrupted. In this case you will receive empty permissions
1071      * and results arrays which should be treated as a cancellation.
1072      * </p>
1073      *
1074      * @param requestCode The request code passed in {@link #requestPermissions(String[], int)}.
1075      * @param permissions The requested permissions. Never null.
1076      * @param grantResults The grant results for the corresponding permissions
1077      *     which is either {@link android.content.pm.PackageManager#PERMISSION_GRANTED}
1078      *     or {@link android.content.pm.PackageManager#PERMISSION_DENIED}. Never null.
1079      *
1080      * @see #requestPermissions(String[], int)
1081      */
1082     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
1083             @NonNull int[] grantResults) {
1084         /* callback - do nothing */
1085     }
1086 
1087     /**
1088      * Gets whether you should show UI with rationale for requesting a permission.
1089      * You should do this only if you do not have the permission and the context in
1090      * which the permission is requested does not clearly communicate to the user
1091      * what would be the benefit from granting this permission.
1092      * <p>
1093      * For example, if you write a camera app, requesting the camera permission
1094      * would be expected by the user and no rationale for why it is requested is
1095      * needed. If however, the app needs location for tagging photos then a non-tech
1096      * savvy user may wonder how location is related to taking photos. In this case
1097      * you may choose to show UI with rationale of requesting this permission.
1098      * </p>
1099      *
1100      * @param permission A permission your app wants to request.
1101      * @return Whether you can show permission rationale UI.
1102      *
1103      * @see Context#checkSelfPermission(String)
1104      * @see #requestPermissions(String[], int)
1105      * @see #onRequestPermissionsResult(int, String[], int[])
1106      */
1107     public boolean shouldShowRequestPermissionRationale(@NonNull String permission) {
1108         if (mHost != null) {
1109             return mHost.onShouldShowRequestPermissionRationale(permission);
1110         }
1111         return false;
1112     }
1113 
1114     /**
1115      * @hide Hack so that DialogFragment can make its Dialog before creating
1116      * its views, and the view construction can use the dialog's context for
1117      * inflation.  Maybe this should become a public API. Note sure.
1118      */
1119     public LayoutInflater getLayoutInflater(Bundle savedInstanceState) {
1120         LayoutInflater result = mHost.onGetLayoutInflater();
1121         getChildFragmentManager(); // Init if needed; use raw implementation below.
1122         LayoutInflaterCompat.setFactory(result, mChildFragmentManager.getLayoutInflaterFactory());
1123         return result;
1124     }
1125 
1126     /**
1127      * Called when a fragment is being created as part of a view layout
1128      * inflation, typically from setting the content view of an activity.  This
1129      * may be called immediately after the fragment is created from a <fragment>
1130      * tag in a layout file.  Note this is <em>before</em> the fragment's
1131      * {@link #onAttach(Activity)} has been called; all you should do here is
1132      * parse the attributes and save them away.
1133      *
1134      * <p>This is called every time the fragment is inflated, even if it is
1135      * being inflated into a new instance with saved state.  It typically makes
1136      * sense to re-parse the parameters each time, to allow them to change with
1137      * different configurations.</p>
1138      *
1139      * <p>Here is a typical implementation of a fragment that can take parameters
1140      * both through attributes supplied here as well from {@link #getArguments()}:</p>
1141      *
1142      * {@sample frameworks/support/samples/Support4Demos/src/com/example/android/supportv4/app/FragmentArgumentsSupport.java
1143      *      fragment}
1144      *
1145      * <p>Note that parsing the XML attributes uses a "styleable" resource.  The
1146      * declaration for the styleable used here is:</p>
1147      *
1148      * {@sample frameworks/support/samples/Support4Demos/res/values/attrs.xml fragment_arguments}
1149      *
1150      * <p>The fragment can then be declared within its activity's content layout
1151      * through a tag like this:</p>
1152      *
1153      * {@sample frameworks/support/samples/Support4Demos/res/layout/fragment_arguments_support.xml from_attributes}
1154      *
1155      * <p>This fragment can also be created dynamically from arguments given
1156      * at runtime in the arguments Bundle; here is an example of doing so at
1157      * creation of the containing activity:</p>
1158      *
1159      * {@sample frameworks/support/samples/Support4Demos/src/com/example/android/supportv4/app/FragmentArgumentsSupport.java
1160      *      create}
1161      *
1162      * @param context The Activity that is inflating this fragment.
1163      * @param attrs The attributes at the tag where the fragment is
1164      * being created.
1165      * @param savedInstanceState If the fragment is being re-created from
1166      * a previous saved state, this is the state.
1167      */
1168     @CallSuper
1169     public void onInflate(Context context, AttributeSet attrs, Bundle savedInstanceState) {
1170         mCalled = true;
1171         final Activity hostActivity = mHost == null ? null : mHost.getActivity();
1172         if (hostActivity != null) {
1173             mCalled = false;
1174             onInflate(hostActivity, attrs, savedInstanceState);
1175         }
1176     }
1177 
1178     /**
1179      * Called when a fragment is being created as part of a view layout
1180      * inflation, typically from setting the content view of an activity.
1181      *
1182      * @deprecated See {@link #onInflate(Context, AttributeSet, Bundle)}.
1183      */
1184     @Deprecated
1185     @CallSuper
1186     public void onInflate(Activity activity, AttributeSet attrs, Bundle savedInstanceState) {
1187         mCalled = true;
1188     }
1189 
1190     /**
1191      * Called when a fragment is attached as a child of this fragment.
1192      *
1193      * <p>This is called after the attached fragment's <code>onAttach</code> and before
1194      * the attached fragment's <code>onCreate</code> if the fragment has not yet had a previous
1195      * call to <code>onCreate</code>.</p>
1196      *
1197      * @param childFragment child fragment being attached
1198      */
1199     public void onAttachFragment(Fragment childFragment) {
1200     }
1201 
1202     /**
1203      * Called when a fragment is first attached to its context.
1204      * {@link #onCreate(Bundle)} will be called after this.
1205      */
1206     @CallSuper
1207     public void onAttach(Context context) {
1208         mCalled = true;
1209         final Activity hostActivity = mHost == null ? null : mHost.getActivity();
1210         if (hostActivity != null) {
1211             mCalled = false;
1212             onAttach(hostActivity);
1213         }
1214     }
1215 
1216     /**
1217      * Called when a fragment is first attached to its activity.
1218      * {@link #onCreate(Bundle)} will be called after this.
1219      *
1220      * @deprecated See {@link #onAttach(Context)}.
1221      */
1222     @Deprecated
1223     @CallSuper
1224     public void onAttach(Activity activity) {
1225         mCalled = true;
1226     }
1227 
1228     /**
1229      * Called when a fragment loads an animation.
1230      */
1231     public Animation onCreateAnimation(int transit, boolean enter, int nextAnim) {
1232         return null;
1233     }
1234 
1235     /**
1236      * Called to do initial creation of a fragment.  This is called after
1237      * {@link #onAttach(Activity)} and before
1238      * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}.
1239      *
1240      * <p>Note that this can be called while the fragment's activity is
1241      * still in the process of being created.  As such, you can not rely
1242      * on things like the activity's content view hierarchy being initialized
1243      * at this point.  If you want to do work once the activity itself is
1244      * created, see {@link #onActivityCreated(Bundle)}.
1245      *
1246      * <p>Any restored child fragments will be created before the base
1247      * <code>Fragment.onCreate</code> method returns.</p>
1248      *
1249      * @param savedInstanceState If the fragment is being re-created from
1250      * a previous saved state, this is the state.
1251      */
1252     @CallSuper
1253     public void onCreate(@Nullable Bundle savedInstanceState) {
1254         mCalled = true;
1255         restoreChildFragmentState(savedInstanceState);
1256         if (mChildFragmentManager != null
1257                 && !mChildFragmentManager.isStateAtLeast(Fragment.CREATED)) {
1258             mChildFragmentManager.dispatchCreate();
1259         }
1260     }
1261 
1262     /**
1263      * Restore the state of the child FragmentManager. Called by either
1264      * {@link #onCreate(Bundle)} for non-retained instance fragments or by
1265      * {@link FragmentManagerImpl#moveToState(Fragment, int, int, int, boolean)}
1266      * for retained instance fragments.
1267      *
1268      * <p><strong>Postcondition:</strong> if there were child fragments to restore,
1269      * the child FragmentManager will be instantiated and brought to the {@link #CREATED} state.
1270      * </p>
1271      *
1272      * @param savedInstanceState the savedInstanceState potentially containing fragment info
1273      */
1274     void restoreChildFragmentState(@Nullable Bundle savedInstanceState) {
1275         if (savedInstanceState != null) {
1276             Parcelable p = savedInstanceState.getParcelable(
1277                     FragmentActivity.FRAGMENTS_TAG);
1278             if (p != null) {
1279                 if (mChildFragmentManager == null) {
1280                     instantiateChildFragmentManager();
1281                 }
1282                 mChildFragmentManager.restoreAllState(p, mChildNonConfig);
1283                 mChildNonConfig = null;
1284                 mChildFragmentManager.dispatchCreate();
1285             }
1286         }
1287     }
1288 
1289     /**
1290      * Called to have the fragment instantiate its user interface view.
1291      * This is optional, and non-graphical fragments can return null (which
1292      * is the default implementation).  This will be called between
1293      * {@link #onCreate(Bundle)} and {@link #onActivityCreated(Bundle)}.
1294      *
1295      * <p>If you return a View from here, you will later be called in
1296      * {@link #onDestroyView} when the view is being released.
1297      *
1298      * @param inflater The LayoutInflater object that can be used to inflate
1299      * any views in the fragment,
1300      * @param container If non-null, this is the parent view that the fragment's
1301      * UI should be attached to.  The fragment should not add the view itself,
1302      * but this can be used to generate the LayoutParams of the view.
1303      * @param savedInstanceState If non-null, this fragment is being re-constructed
1304      * from a previous saved state as given here.
1305      *
1306      * @return Return the View for the fragment's UI, or null.
1307      */
1308     @Nullable
1309     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
1310             @Nullable Bundle savedInstanceState) {
1311         return null;
1312     }
1313 
1314     /**
1315      * Called immediately after {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}
1316      * has returned, but before any saved state has been restored in to the view.
1317      * This gives subclasses a chance to initialize themselves once
1318      * they know their view hierarchy has been completely created.  The fragment's
1319      * view hierarchy is not however attached to its parent at this point.
1320      * @param view The View returned by {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}.
1321      * @param savedInstanceState If non-null, this fragment is being re-constructed
1322      * from a previous saved state as given here.
1323      */
1324     public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
1325     }
1326 
1327     /**
1328      * Get the root view for the fragment's layout (the one returned by {@link #onCreateView}),
1329      * if provided.
1330      *
1331      * @return The fragment's root view, or null if it has no layout.
1332      */
1333     @Nullable
1334     public View getView() {
1335         return mView;
1336     }
1337 
1338     /**
1339      * Called when the fragment's activity has been created and this
1340      * fragment's view hierarchy instantiated.  It can be used to do final
1341      * initialization once these pieces are in place, such as retrieving
1342      * views or restoring state.  It is also useful for fragments that use
1343      * {@link #setRetainInstance(boolean)} to retain their instance,
1344      * as this callback tells the fragment when it is fully associated with
1345      * the new activity instance.  This is called after {@link #onCreateView}
1346      * and before {@link #onViewStateRestored(Bundle)}.
1347      *
1348      * @param savedInstanceState If the fragment is being re-created from
1349      * a previous saved state, this is the state.
1350      */
1351     @CallSuper
1352     public void onActivityCreated(@Nullable Bundle savedInstanceState) {
1353         mCalled = true;
1354     }
1355 
1356     /**
1357      * Called when all saved state has been restored into the view hierarchy
1358      * of the fragment.  This can be used to do initialization based on saved
1359      * state that you are letting the view hierarchy track itself, such as
1360      * whether check box widgets are currently checked.  This is called
1361      * after {@link #onActivityCreated(Bundle)} and before
1362      * {@link #onStart()}.
1363      *
1364      * @param savedInstanceState If the fragment is being re-created from
1365      * a previous saved state, this is the state.
1366      */
1367     @CallSuper
1368     public void onViewStateRestored(@Nullable Bundle savedInstanceState) {
1369         mCalled = true;
1370     }
1371 
1372     /**
1373      * Called when the Fragment is visible to the user.  This is generally
1374      * tied to {@link Activity#onStart() Activity.onStart} of the containing
1375      * Activity's lifecycle.
1376      */
1377     @CallSuper
1378     public void onStart() {
1379         mCalled = true;
1380 
1381         if (!mLoadersStarted) {
1382             mLoadersStarted = true;
1383             if (!mCheckedForLoaderManager) {
1384                 mCheckedForLoaderManager = true;
1385                 mLoaderManager = mHost.getLoaderManager(mWho, mLoadersStarted, false);
1386             }
1387             if (mLoaderManager != null) {
1388                 mLoaderManager.doStart();
1389             }
1390         }
1391     }
1392 
1393     /**
1394      * Called when the fragment is visible to the user and actively running.
1395      * This is generally
1396      * tied to {@link Activity#onResume() Activity.onResume} of the containing
1397      * Activity's lifecycle.
1398      */
1399     @CallSuper
1400     public void onResume() {
1401         mCalled = true;
1402     }
1403 
1404     /**
1405      * Called to ask the fragment to save its current dynamic state, so it
1406      * can later be reconstructed in a new instance of its process is
1407      * restarted.  If a new instance of the fragment later needs to be
1408      * created, the data you place in the Bundle here will be available
1409      * in the Bundle given to {@link #onCreate(Bundle)},
1410      * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}, and
1411      * {@link #onActivityCreated(Bundle)}.
1412      *
1413      * <p>This corresponds to {@link Activity#onSaveInstanceState(Bundle)
1414      * Activity.onSaveInstanceState(Bundle)} and most of the discussion there
1415      * applies here as well.  Note however: <em>this method may be called
1416      * at any time before {@link #onDestroy()}</em>.  There are many situations
1417      * where a fragment may be mostly torn down (such as when placed on the
1418      * back stack with no UI showing), but its state will not be saved until
1419      * its owning activity actually needs to save its state.
1420      *
1421      * @param outState Bundle in which to place your saved state.
1422      */
1423     public void onSaveInstanceState(Bundle outState) {
1424     }
1425 
1426     /**
1427      * Called when the Fragment's activity changes from fullscreen mode to multi-window mode and
1428      * visa-versa. This is generally tied to {@link Activity#onMultiWindowModeChanged} of the
1429      * containing Activity.
1430      *
1431      * @param isInMultiWindowMode True if the activity is in multi-window mode.
1432      */
1433     public void onMultiWindowModeChanged(boolean isInMultiWindowMode) {
1434     }
1435 
1436     /**
1437      * Called by the system when the activity changes to and from picture-in-picture mode. This is
1438      * generally tied to {@link Activity#onPictureInPictureModeChanged} of the containing Activity.
1439      *
1440      * @param isInPictureInPictureMode True if the activity is in picture-in-picture mode.
1441      */
1442     public void onPictureInPictureModeChanged(boolean isInPictureInPictureMode) {
1443     }
1444 
1445     @Override
1446     @CallSuper
1447     public void onConfigurationChanged(Configuration newConfig) {
1448         mCalled = true;
1449     }
1450 
1451     /**
1452      * Called when the Fragment is no longer resumed.  This is generally
1453      * tied to {@link Activity#onPause() Activity.onPause} of the containing
1454      * Activity's lifecycle.
1455      */
1456     @CallSuper
1457     public void onPause() {
1458         mCalled = true;
1459     }
1460 
1461     /**
1462      * Called when the Fragment is no longer started.  This is generally
1463      * tied to {@link Activity#onStop() Activity.onStop} of the containing
1464      * Activity's lifecycle.
1465      */
1466     @CallSuper
1467     public void onStop() {
1468         mCalled = true;
1469     }
1470 
1471     @Override
1472     @CallSuper
1473     public void onLowMemory() {
1474         mCalled = true;
1475     }
1476 
1477     /**
1478      * Called when the view previously created by {@link #onCreateView} has
1479      * been detached from the fragment.  The next time the fragment needs
1480      * to be displayed, a new view will be created.  This is called
1481      * after {@link #onStop()} and before {@link #onDestroy()}.  It is called
1482      * <em>regardless</em> of whether {@link #onCreateView} returned a
1483      * non-null view.  Internally it is called after the view's state has
1484      * been saved but before it has been removed from its parent.
1485      */
1486     @CallSuper
1487     public void onDestroyView() {
1488         mCalled = true;
1489     }
1490 
1491     /**
1492      * Called when the fragment is no longer in use.  This is called
1493      * after {@link #onStop()} and before {@link #onDetach()}.
1494      */
1495     @CallSuper
1496     public void onDestroy() {
1497         mCalled = true;
1498         //Log.v("foo", "onDestroy: mCheckedForLoaderManager=" + mCheckedForLoaderManager
1499         //        + " mLoaderManager=" + mLoaderManager);
1500         if (!mCheckedForLoaderManager) {
1501             mCheckedForLoaderManager = true;
1502             mLoaderManager = mHost.getLoaderManager(mWho, mLoadersStarted, false);
1503         }
1504         if (mLoaderManager != null) {
1505             mLoaderManager.doDestroy();
1506         }
1507     }
1508 
1509     /**
1510      * Called by the fragment manager once this fragment has been removed,
1511      * so that we don't have any left-over state if the application decides
1512      * to re-use the instance.  This only clears state that the framework
1513      * internally manages, not things the application sets.
1514      */
1515     void initState() {
1516         mIndex = -1;
1517         mWho = null;
1518         mAdded = false;
1519         mRemoving = false;
1520         mFromLayout = false;
1521         mInLayout = false;
1522         mRestored = false;
1523         mBackStackNesting = 0;
1524         mFragmentManager = null;
1525         mChildFragmentManager = null;
1526         mHost = null;
1527         mFragmentId = 0;
1528         mContainerId = 0;
1529         mTag = null;
1530         mHidden = false;
1531         mDetached = false;
1532         mRetaining = false;
1533         mLoaderManager = null;
1534         mLoadersStarted = false;
1535         mCheckedForLoaderManager = false;
1536     }
1537 
1538     /**
1539      * Called when the fragment is no longer attached to its activity.  This
1540      * is called after {@link #onDestroy()}.
1541      */
1542     @CallSuper
1543     public void onDetach() {
1544         mCalled = true;
1545     }
1546 
1547     /**
1548      * Initialize the contents of the Fragment host's standard options menu.  You
1549      * should place your menu items in to <var>menu</var>.  For this method
1550      * to be called, you must have first called {@link #setHasOptionsMenu}.  See
1551      * {@link Activity#onCreateOptionsMenu(Menu) Activity.onCreateOptionsMenu}
1552      * for more information.
1553      *
1554      * @param menu The options menu in which you place your items.
1555      *
1556      * @see #setHasOptionsMenu
1557      * @see #onPrepareOptionsMenu
1558      * @see #onOptionsItemSelected
1559      */
1560     public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
1561     }
1562 
1563     /**
1564      * Prepare the Fragment host's standard options menu to be displayed.  This is
1565      * called right before the menu is shown, every time it is shown.  You can
1566      * use this method to efficiently enable/disable items or otherwise
1567      * dynamically modify the contents.  See
1568      * {@link Activity#onPrepareOptionsMenu(Menu) Activity.onPrepareOptionsMenu}
1569      * for more information.
1570      *
1571      * @param menu The options menu as last shown or first initialized by
1572      *             onCreateOptionsMenu().
1573      *
1574      * @see #setHasOptionsMenu
1575      * @see #onCreateOptionsMenu
1576      */
1577     public void onPrepareOptionsMenu(Menu menu) {
1578     }
1579 
1580     /**
1581      * Called when this fragment's option menu items are no longer being
1582      * included in the overall options menu.  Receiving this call means that
1583      * the menu needed to be rebuilt, but this fragment's items were not
1584      * included in the newly built menu (its {@link #onCreateOptionsMenu(Menu, MenuInflater)}
1585      * was not called).
1586      */
1587     public void onDestroyOptionsMenu() {
1588     }
1589 
1590     /**
1591      * This hook is called whenever an item in your options menu is selected.
1592      * The default implementation simply returns false to have the normal
1593      * processing happen (calling the item's Runnable or sending a message to
1594      * its Handler as appropriate).  You can use this method for any items
1595      * for which you would like to do processing without those other
1596      * facilities.
1597      *
1598      * <p>Derived classes should call through to the base class for it to
1599      * perform the default menu handling.
1600      *
1601      * @param item The menu item that was selected.
1602      *
1603      * @return boolean Return false to allow normal menu processing to
1604      *         proceed, true to consume it here.
1605      *
1606      * @see #onCreateOptionsMenu
1607      */
1608     public boolean onOptionsItemSelected(MenuItem item) {
1609         return false;
1610     }
1611 
1612     /**
1613      * This hook is called whenever the options menu is being closed (either by the user canceling
1614      * the menu with the back/menu button, or when an item is selected).
1615      *
1616      * @param menu The options menu as last shown or first initialized by
1617      *             onCreateOptionsMenu().
1618      */
1619     public void onOptionsMenuClosed(Menu menu) {
1620     }
1621 
1622     /**
1623      * Called when a context menu for the {@code view} is about to be shown.
1624      * Unlike {@link #onCreateOptionsMenu}, this will be called every
1625      * time the context menu is about to be shown and should be populated for
1626      * the view (or item inside the view for {@link AdapterView} subclasses,
1627      * this can be found in the {@code menuInfo})).
1628      * <p>
1629      * Use {@link #onContextItemSelected(android.view.MenuItem)} to know when an
1630      * item has been selected.
1631      * <p>
1632      * The default implementation calls up to
1633      * {@link Activity#onCreateContextMenu Activity.onCreateContextMenu}, though
1634      * you can not call this implementation if you don't want that behavior.
1635      * <p>
1636      * It is not safe to hold onto the context menu after this method returns.
1637      * {@inheritDoc}
1638      */
1639     @Override
1640     public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
1641         getActivity().onCreateContextMenu(menu, v, menuInfo);
1642     }
1643 
1644     /**
1645      * Registers a context menu to be shown for the given view (multiple views
1646      * can show the context menu). This method will set the
1647      * {@link OnCreateContextMenuListener} on the view to this fragment, so
1648      * {@link #onCreateContextMenu(ContextMenu, View, ContextMenuInfo)} will be
1649      * called when it is time to show the context menu.
1650      *
1651      * @see #unregisterForContextMenu(View)
1652      * @param view The view that should show a context menu.
1653      */
1654     public void registerForContextMenu(View view) {
1655         view.setOnCreateContextMenuListener(this);
1656     }
1657 
1658     /**
1659      * Prevents a context menu to be shown for the given view. This method will
1660      * remove the {@link OnCreateContextMenuListener} on the view.
1661      *
1662      * @see #registerForContextMenu(View)
1663      * @param view The view that should stop showing a context menu.
1664      */
1665     public void unregisterForContextMenu(View view) {
1666         view.setOnCreateContextMenuListener(null);
1667     }
1668 
1669     /**
1670      * This hook is called whenever an item in a context menu is selected. The
1671      * default implementation simply returns false to have the normal processing
1672      * happen (calling the item's Runnable or sending a message to its Handler
1673      * as appropriate). You can use this method for any items for which you
1674      * would like to do processing without those other facilities.
1675      * <p>
1676      * Use {@link MenuItem#getMenuInfo()} to get extra information set by the
1677      * View that added this menu item.
1678      * <p>
1679      * Derived classes should call through to the base class for it to perform
1680      * the default menu handling.
1681      *
1682      * @param item The context menu item that was selected.
1683      * @return boolean Return false to allow normal context menu processing to
1684      *         proceed, true to consume it here.
1685      */
1686     public boolean onContextItemSelected(MenuItem item) {
1687         return false;
1688     }
1689 
1690     /**
1691      * When custom transitions are used with Fragments, the enter transition callback
1692      * is called when this Fragment is attached or detached when not popping the back stack.
1693      *
1694      * @param callback Used to manipulate the shared element transitions on this Fragment
1695      *                 when added not as a pop from the back stack.
1696      */
1697     public void setEnterSharedElementCallback(SharedElementCallback callback) {
1698         mEnterTransitionCallback = callback;
1699     }
1700 
1701     /**
1702      * When custom transitions are used with Fragments, the exit transition callback
1703      * is called when this Fragment is attached or detached when popping the back stack.
1704      *
1705      * @param callback Used to manipulate the shared element transitions on this Fragment
1706      *                 when added as a pop from the back stack.
1707      */
1708     public void setExitSharedElementCallback(SharedElementCallback callback) {
1709         mExitTransitionCallback = callback;
1710     }
1711 
1712     /**
1713      * Sets the Transition that will be used to move Views into the initial scene. The entering
1714      * Views will be those that are regular Views or ViewGroups that have
1715      * {@link ViewGroup#isTransitionGroup} return true. Typical Transitions will extend
1716      * {@link android.transition.Visibility} as entering is governed by changing visibility from
1717      * {@link View#INVISIBLE} to {@link View#VISIBLE}. If <code>transition</code> is null,
1718      * entering Views will remain unaffected.
1719      *
1720      * @param transition The Transition to use to move Views into the initial Scene.
1721      */
1722     public void setEnterTransition(Object transition) {
1723         mEnterTransition = transition;
1724     }
1725 
1726     /**
1727      * Returns the Transition that will be used to move Views into the initial scene. The entering
1728      * Views will be those that are regular Views or ViewGroups that have
1729      * {@link ViewGroup#isTransitionGroup} return true. Typical Transitions will extend
1730      * {@link android.transition.Visibility} as entering is governed by changing visibility from
1731      * {@link View#INVISIBLE} to {@link View#VISIBLE}.
1732      *
1733      * @return the Transition to use to move Views into the initial Scene.
1734      */
1735     public Object getEnterTransition() {
1736         return mEnterTransition;
1737     }
1738 
1739     /**
1740      * Sets the Transition that will be used to move Views out of the scene when the Fragment is
1741      * preparing to be removed, hidden, or detached because of popping the back stack. The exiting
1742      * Views will be those that are regular Views or ViewGroups that have
1743      * {@link ViewGroup#isTransitionGroup} return true. Typical Transitions will extend
1744      * {@link android.transition.Visibility} as entering is governed by changing visibility from
1745      * {@link View#VISIBLE} to {@link View#INVISIBLE}. If <code>transition</code> is null,
1746      * entering Views will remain unaffected. If nothing is set, the default will be to
1747      * use the same value as set in {@link #setEnterTransition(Object)}.
1748      *
1749      * @param transition The Transition to use to move Views out of the Scene when the Fragment
1750      *                   is preparing to close. <code>transition</code> must be an
1751      *                   android.transition.Transition.
1752      */
1753     public void setReturnTransition(Object transition) {
1754         mReturnTransition = transition;
1755     }
1756 
1757     /**
1758      * Returns the Transition that will be used to move Views out of the scene when the Fragment is
1759      * preparing to be removed, hidden, or detached because of popping the back stack. The exiting
1760      * Views will be those that are regular Views or ViewGroups that have
1761      * {@link ViewGroup#isTransitionGroup} return true. Typical Transitions will extend
1762      * {@link android.transition.Visibility} as entering is governed by changing visibility from
1763      * {@link View#VISIBLE} to {@link View#INVISIBLE}. If <code>transition</code> is null,
1764      * entering Views will remain unaffected.
1765      *
1766      * @return the Transition to use to move Views out of the Scene when the Fragment
1767      *         is preparing to close.
1768      */
1769     public Object getReturnTransition() {
1770         return mReturnTransition == USE_DEFAULT_TRANSITION ? getEnterTransition()
1771                 : mReturnTransition;
1772     }
1773 
1774     /**
1775      * Sets the Transition that will be used to move Views out of the scene when the
1776      * fragment is removed, hidden, or detached when not popping the back stack.
1777      * The exiting Views will be those that are regular Views or ViewGroups that
1778      * have {@link ViewGroup#isTransitionGroup} return true. Typical Transitions will extend
1779      * {@link android.transition.Visibility} as exiting is governed by changing visibility
1780      * from {@link View#VISIBLE} to {@link View#INVISIBLE}. If transition is null, the views will
1781      * remain unaffected.
1782      *
1783      * @param transition The Transition to use to move Views out of the Scene when the Fragment
1784      *                   is being closed not due to popping the back stack. <code>transition</code>
1785      *                   must be an android.transition.Transition.
1786      */
1787     public void setExitTransition(Object transition) {
1788         mExitTransition = transition;
1789     }
1790 
1791     /**
1792      * Returns the Transition that will be used to move Views out of the scene when the
1793      * fragment is removed, hidden, or detached when not popping the back stack.
1794      * The exiting Views will be those that are regular Views or ViewGroups that
1795      * have {@link ViewGroup#isTransitionGroup} return true. Typical Transitions will extend
1796      * {@link android.transition.Visibility} as exiting is governed by changing visibility
1797      * from {@link View#VISIBLE} to {@link View#INVISIBLE}. If transition is null, the views will
1798      * remain unaffected.
1799      *
1800      * @return the Transition to use to move Views out of the Scene when the Fragment
1801      *         is being closed not due to popping the back stack.
1802      */
1803     public Object getExitTransition() {
1804         return mExitTransition;
1805     }
1806 
1807     /**
1808      * Sets the Transition that will be used to move Views in to the scene when returning due
1809      * to popping a back stack. The entering Views will be those that are regular Views
1810      * or ViewGroups that have {@link ViewGroup#isTransitionGroup} return true. Typical Transitions
1811      * will extend {@link android.transition.Visibility} as exiting is governed by changing
1812      * visibility from {@link View#VISIBLE} to {@link View#INVISIBLE}. If transition is null,
1813      * the views will remain unaffected. If nothing is set, the default will be to use the same
1814      * transition as {@link #setExitTransition(Object)}.
1815      *
1816      * @param transition The Transition to use to move Views into the scene when reentering from a
1817      *                   previously-started Activity. <code>transition</code>
1818      *                   must be an android.transition.Transition.
1819      */
1820     public void setReenterTransition(Object transition) {
1821         mReenterTransition = transition;
1822     }
1823 
1824     /**
1825      * Returns the Transition that will be used to move Views in to the scene when returning due
1826      * to popping a back stack. The entering Views will be those that are regular Views
1827      * or ViewGroups that have {@link ViewGroup#isTransitionGroup} return true. Typical Transitions
1828      * will extend {@link android.transition.Visibility} as exiting is governed by changing
1829      * visibility from {@link View#VISIBLE} to {@link View#INVISIBLE}. If transition is null,
1830      * the views will remain unaffected. If nothing is set, the default will be to use the same
1831      * transition as {@link #setExitTransition(Object)}.
1832      *
1833      * @return the Transition to use to move Views into the scene when reentering from a
1834      *                   previously-started Activity.
1835      */
1836     public Object getReenterTransition() {
1837         return mReenterTransition == USE_DEFAULT_TRANSITION ? getExitTransition()
1838                 : mReenterTransition;
1839     }
1840 
1841     /**
1842      * Sets the Transition that will be used for shared elements transferred into the content
1843      * Scene. Typical Transitions will affect size and location, such as
1844      * {@link android.transition.ChangeBounds}. A null
1845      * value will cause transferred shared elements to blink to the final position.
1846      *
1847      * @param transition The Transition to use for shared elements transferred into the content
1848      *                   Scene.  <code>transition</code> must be an android.transition.Transition.
1849      */
1850     public void setSharedElementEnterTransition(Object transition) {
1851         mSharedElementEnterTransition = transition;
1852     }
1853 
1854     /**
1855      * Returns the Transition that will be used for shared elements transferred into the content
1856      * Scene. Typical Transitions will affect size and location, such as
1857      * {@link android.transition.ChangeBounds}. A null
1858      * value will cause transferred shared elements to blink to the final position.
1859      *
1860      * @return The Transition to use for shared elements transferred into the content
1861      *                   Scene.
1862      */
1863     public Object getSharedElementEnterTransition() {
1864         return mSharedElementEnterTransition;
1865     }
1866 
1867     /**
1868      * Sets the Transition that will be used for shared elements transferred back during a
1869      * pop of the back stack. This Transition acts in the leaving Fragment.
1870      * Typical Transitions will affect size and location, such as
1871      * {@link android.transition.ChangeBounds}. A null
1872      * value will cause transferred shared elements to blink to the final position.
1873      * If no value is set, the default will be to use the same value as
1874      * {@link #setSharedElementEnterTransition(Object)}.
1875      *
1876      * @param transition The Transition to use for shared elements transferred out of the content
1877      *                   Scene. <code>transition</code> must be an android.transition.Transition.
1878      */
1879     public void setSharedElementReturnTransition(Object transition) {
1880         mSharedElementReturnTransition = transition;
1881     }
1882 
1883     /**
1884      * Return the Transition that will be used for shared elements transferred back during a
1885      * pop of the back stack. This Transition acts in the leaving Fragment.
1886      * Typical Transitions will affect size and location, such as
1887      * {@link android.transition.ChangeBounds}. A null
1888      * value will cause transferred shared elements to blink to the final position.
1889      * If no value is set, the default will be to use the same value as
1890      * {@link #setSharedElementEnterTransition(Object)}.
1891      *
1892      * @return The Transition to use for shared elements transferred out of the content
1893      *                   Scene.
1894      */
1895     public Object getSharedElementReturnTransition() {
1896         return mSharedElementReturnTransition == USE_DEFAULT_TRANSITION ?
1897                 getSharedElementEnterTransition() : mSharedElementReturnTransition;
1898     }
1899 
1900     /**
1901      * Sets whether the the exit transition and enter transition overlap or not.
1902      * When true, the enter transition will start as soon as possible. When false, the
1903      * enter transition will wait until the exit transition completes before starting.
1904      *
1905      * @param allow true to start the enter transition when possible or false to
1906      *              wait until the exiting transition completes.
1907      */
1908     public void setAllowEnterTransitionOverlap(boolean allow) {
1909         mAllowEnterTransitionOverlap = allow;
1910     }
1911 
1912     /**
1913      * Returns whether the the exit transition and enter transition overlap or not.
1914      * When true, the enter transition will start as soon as possible. When false, the
1915      * enter transition will wait until the exit transition completes before starting.
1916      *
1917      * @return true when the enter transition should start as soon as possible or false to
1918      * when it should wait until the exiting transition completes.
1919      */
1920     public boolean getAllowEnterTransitionOverlap() {
1921         return (mAllowEnterTransitionOverlap == null) ? true : mAllowEnterTransitionOverlap;
1922     }
1923 
1924     /**
1925      * Sets whether the the return transition and reenter transition overlap or not.
1926      * When true, the reenter transition will start as soon as possible. When false, the
1927      * reenter transition will wait until the return transition completes before starting.
1928      *
1929      * @param allow true to start the reenter transition when possible or false to wait until the
1930      *              return transition completes.
1931      */
1932     public void setAllowReturnTransitionOverlap(boolean allow) {
1933         mAllowReturnTransitionOverlap = allow;
1934     }
1935 
1936     /**
1937      * Returns whether the the return transition and reenter transition overlap or not.
1938      * When true, the reenter transition will start as soon as possible. When false, the
1939      * reenter transition will wait until the return transition completes before starting.
1940      *
1941      * @return true to start the reenter transition when possible or false to wait until the
1942      *         return transition completes.
1943      */
1944     public boolean getAllowReturnTransitionOverlap() {
1945         return (mAllowReturnTransitionOverlap == null) ? true : mAllowReturnTransitionOverlap;
1946     }
1947 
1948     /**
1949      * Print the Fragments's state into the given stream.
1950      *
1951      * @param prefix Text to print at the front of each line.
1952      * @param fd The raw file descriptor that the dump is being sent to.
1953      * @param writer The PrintWriter to which you should dump your state.  This will be
1954      * closed for you after you return.
1955      * @param args additional arguments to the dump request.
1956      */
1957     public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args) {
1958         writer.print(prefix); writer.print("mFragmentId=#");
1959                 writer.print(Integer.toHexString(mFragmentId));
1960                 writer.print(" mContainerId=#");
1961                 writer.print(Integer.toHexString(mContainerId));
1962                 writer.print(" mTag="); writer.println(mTag);
1963         writer.print(prefix); writer.print("mState="); writer.print(mState);
1964                 writer.print(" mIndex="); writer.print(mIndex);
1965                 writer.print(" mWho="); writer.print(mWho);
1966                 writer.print(" mBackStackNesting="); writer.println(mBackStackNesting);
1967         writer.print(prefix); writer.print("mAdded="); writer.print(mAdded);
1968                 writer.print(" mRemoving="); writer.print(mRemoving);
1969                 writer.print(" mFromLayout="); writer.print(mFromLayout);
1970                 writer.print(" mInLayout="); writer.println(mInLayout);
1971         writer.print(prefix); writer.print("mHidden="); writer.print(mHidden);
1972                 writer.print(" mDetached="); writer.print(mDetached);
1973                 writer.print(" mMenuVisible="); writer.print(mMenuVisible);
1974                 writer.print(" mHasMenu="); writer.println(mHasMenu);
1975         writer.print(prefix); writer.print("mRetainInstance="); writer.print(mRetainInstance);
1976                 writer.print(" mRetaining="); writer.print(mRetaining);
1977                 writer.print(" mUserVisibleHint="); writer.println(mUserVisibleHint);
1978         if (mFragmentManager != null) {
1979             writer.print(prefix); writer.print("mFragmentManager=");
1980                     writer.println(mFragmentManager);
1981         }
1982         if (mHost != null) {
1983             writer.print(prefix); writer.print("mHost=");
1984                     writer.println(mHost);
1985         }
1986         if (mParentFragment != null) {
1987             writer.print(prefix); writer.print("mParentFragment=");
1988                     writer.println(mParentFragment);
1989         }
1990         if (mArguments != null) {
1991             writer.print(prefix); writer.print("mArguments="); writer.println(mArguments);
1992         }
1993         if (mSavedFragmentState != null) {
1994             writer.print(prefix); writer.print("mSavedFragmentState=");
1995                     writer.println(mSavedFragmentState);
1996         }
1997         if (mSavedViewState != null) {
1998             writer.print(prefix); writer.print("mSavedViewState=");
1999                     writer.println(mSavedViewState);
2000         }
2001         if (mTarget != null) {
2002             writer.print(prefix); writer.print("mTarget="); writer.print(mTarget);
2003                     writer.print(" mTargetRequestCode=");
2004                     writer.println(mTargetRequestCode);
2005         }
2006         if (mNextAnim != 0) {
2007             writer.print(prefix); writer.print("mNextAnim="); writer.println(mNextAnim);
2008         }
2009         if (mContainer != null) {
2010             writer.print(prefix); writer.print("mContainer="); writer.println(mContainer);
2011         }
2012         if (mView != null) {
2013             writer.print(prefix); writer.print("mView="); writer.println(mView);
2014         }
2015         if (mInnerView != null) {
2016             writer.print(prefix); writer.print("mInnerView="); writer.println(mView);
2017         }
2018         if (mAnimatingAway != null) {
2019             writer.print(prefix); writer.print("mAnimatingAway="); writer.println(mAnimatingAway);
2020             writer.print(prefix); writer.print("mStateAfterAnimating=");
2021                     writer.println(mStateAfterAnimating);
2022         }
2023         if (mLoaderManager != null) {
2024             writer.print(prefix); writer.println("Loader Manager:");
2025             mLoaderManager.dump(prefix + "  ", fd, writer, args);
2026         }
2027         if (mChildFragmentManager != null) {
2028             writer.print(prefix); writer.println("Child " + mChildFragmentManager + ":");
2029             mChildFragmentManager.dump(prefix + "  ", fd, writer, args);
2030         }
2031     }
2032 
2033     Fragment findFragmentByWho(String who) {
2034         if (who.equals(mWho)) {
2035             return this;
2036         }
2037         if (mChildFragmentManager != null) {
2038             return mChildFragmentManager.findFragmentByWho(who);
2039         }
2040         return null;
2041     }
2042 
2043     void instantiateChildFragmentManager() {
2044         mChildFragmentManager = new FragmentManagerImpl();
2045         mChildFragmentManager.attachController(mHost, new FragmentContainer() {
2046             @Override
2047             @Nullable
2048             public View onFindViewById(int id) {
2049                 if (mView == null) {
2050                     throw new IllegalStateException("Fragment does not have a view");
2051                 }
2052                 return mView.findViewById(id);
2053             }
2054 
2055             @Override
2056             public boolean onHasView() {
2057                 return (mView != null);
2058             }
2059         }, this);
2060     }
2061 
2062     void performCreate(Bundle savedInstanceState) {
2063         if (mChildFragmentManager != null) {
2064             mChildFragmentManager.noteStateNotSaved();
2065         }
2066         mState = CREATED;
2067         mCalled = false;
2068         onCreate(savedInstanceState);
2069         if (!mCalled) {
2070             throw new SuperNotCalledException("Fragment " + this
2071                     + " did not call through to super.onCreate()");
2072         }
2073     }
2074 
2075     View performCreateView(LayoutInflater inflater, ViewGroup container,
2076             Bundle savedInstanceState) {
2077         if (mChildFragmentManager != null) {
2078             mChildFragmentManager.noteStateNotSaved();
2079         }
2080         return onCreateView(inflater, container, savedInstanceState);
2081     }
2082 
2083     void performActivityCreated(Bundle savedInstanceState) {
2084         if (mChildFragmentManager != null) {
2085             mChildFragmentManager.noteStateNotSaved();
2086         }
2087         mState = ACTIVITY_CREATED;
2088         mCalled = false;
2089         onActivityCreated(savedInstanceState);
2090         if (!mCalled) {
2091             throw new SuperNotCalledException("Fragment " + this
2092                     + " did not call through to super.onActivityCreated()");
2093         }
2094         if (mChildFragmentManager != null) {
2095             mChildFragmentManager.dispatchActivityCreated();
2096         }
2097     }
2098 
2099     void performStart() {
2100         if (mChildFragmentManager != null) {
2101             mChildFragmentManager.noteStateNotSaved();
2102             mChildFragmentManager.execPendingActions();
2103         }
2104         mState = STARTED;
2105         mCalled = false;
2106         onStart();
2107         if (!mCalled) {
2108             throw new SuperNotCalledException("Fragment " + this
2109                     + " did not call through to super.onStart()");
2110         }
2111         if (mChildFragmentManager != null) {
2112             mChildFragmentManager.dispatchStart();
2113         }
2114         if (mLoaderManager != null) {
2115             mLoaderManager.doReportStart();
2116         }
2117     }
2118 
2119     void performResume() {
2120         if (mChildFragmentManager != null) {
2121             mChildFragmentManager.noteStateNotSaved();
2122             mChildFragmentManager.execPendingActions();
2123         }
2124         mState = RESUMED;
2125         mCalled = false;
2126         onResume();
2127         if (!mCalled) {
2128             throw new SuperNotCalledException("Fragment " + this
2129                     + " did not call through to super.onResume()");
2130         }
2131         if (mChildFragmentManager != null) {
2132             mChildFragmentManager.dispatchResume();
2133             mChildFragmentManager.execPendingActions();
2134         }
2135     }
2136 
2137     void performMultiWindowModeChanged(boolean isInMultiWindowMode) {
2138         onMultiWindowModeChanged(isInMultiWindowMode);
2139         if (mChildFragmentManager != null) {
2140             mChildFragmentManager.dispatchMultiWindowModeChanged(isInMultiWindowMode);
2141         }
2142     }
2143 
2144     void performPictureInPictureModeChanged(boolean isInPictureInPictureMode) {
2145         onPictureInPictureModeChanged(isInPictureInPictureMode);
2146         if (mChildFragmentManager != null) {
2147             mChildFragmentManager.dispatchPictureInPictureModeChanged(isInPictureInPictureMode);
2148         }
2149     }
2150 
2151     void performConfigurationChanged(Configuration newConfig) {
2152         onConfigurationChanged(newConfig);
2153         if (mChildFragmentManager != null) {
2154             mChildFragmentManager.dispatchConfigurationChanged(newConfig);
2155         }
2156     }
2157 
2158     void performLowMemory() {
2159         onLowMemory();
2160         if (mChildFragmentManager != null) {
2161             mChildFragmentManager.dispatchLowMemory();
2162         }
2163     }
2164 
2165     /*
2166     void performTrimMemory(int level) {
2167         onTrimMemory(level);
2168         if (mChildFragmentManager != null) {
2169             mChildFragmentManager.dispatchTrimMemory(level);
2170         }
2171     }
2172     */
2173 
2174     boolean performCreateOptionsMenu(Menu menu, MenuInflater inflater) {
2175         boolean show = false;
2176         if (!mHidden) {
2177             if (mHasMenu && mMenuVisible) {
2178                 show = true;
2179                 onCreateOptionsMenu(menu, inflater);
2180             }
2181             if (mChildFragmentManager != null) {
2182                 show |= mChildFragmentManager.dispatchCreateOptionsMenu(menu, inflater);
2183             }
2184         }
2185         return show;
2186     }
2187 
2188     boolean performPrepareOptionsMenu(Menu menu) {
2189         boolean show = false;
2190         if (!mHidden) {
2191             if (mHasMenu && mMenuVisible) {
2192                 show = true;
2193                 onPrepareOptionsMenu(menu);
2194             }
2195             if (mChildFragmentManager != null) {
2196                 show |= mChildFragmentManager.dispatchPrepareOptionsMenu(menu);
2197             }
2198         }
2199         return show;
2200     }
2201 
2202     boolean performOptionsItemSelected(MenuItem item) {
2203         if (!mHidden) {
2204             if (mHasMenu && mMenuVisible) {
2205                 if (onOptionsItemSelected(item)) {
2206                     return true;
2207                 }
2208             }
2209             if (mChildFragmentManager != null) {
2210                 if (mChildFragmentManager.dispatchOptionsItemSelected(item)) {
2211                     return true;
2212                 }
2213             }
2214         }
2215         return false;
2216     }
2217 
2218     boolean performContextItemSelected(MenuItem item) {
2219         if (!mHidden) {
2220             if (onContextItemSelected(item)) {
2221                 return true;
2222             }
2223             if (mChildFragmentManager != null) {
2224                 if (mChildFragmentManager.dispatchContextItemSelected(item)) {
2225                     return true;
2226                 }
2227             }
2228         }
2229         return false;
2230     }
2231 
2232     void performOptionsMenuClosed(Menu menu) {
2233         if (!mHidden) {
2234             if (mHasMenu && mMenuVisible) {
2235                 onOptionsMenuClosed(menu);
2236             }
2237             if (mChildFragmentManager != null) {
2238                 mChildFragmentManager.dispatchOptionsMenuClosed(menu);
2239             }
2240         }
2241     }
2242 
2243     void performSaveInstanceState(Bundle outState) {
2244         onSaveInstanceState(outState);
2245         if (mChildFragmentManager != null) {
2246             Parcelable p = mChildFragmentManager.saveAllState();
2247             if (p != null) {
2248                 outState.putParcelable(FragmentActivity.FRAGMENTS_TAG, p);
2249             }
2250         }
2251     }
2252 
2253     void performPause() {
2254         if (mChildFragmentManager != null) {
2255             mChildFragmentManager.dispatchPause();
2256         }
2257         mState = STARTED;
2258         mCalled = false;
2259         onPause();
2260         if (!mCalled) {
2261             throw new SuperNotCalledException("Fragment " + this
2262                     + " did not call through to super.onPause()");
2263         }
2264     }
2265 
2266     void performStop() {
2267         if (mChildFragmentManager != null) {
2268             mChildFragmentManager.dispatchStop();
2269         }
2270         mState = STOPPED;
2271         mCalled = false;
2272         onStop();
2273         if (!mCalled) {
2274             throw new SuperNotCalledException("Fragment " + this
2275                     + " did not call through to super.onStop()");
2276         }
2277     }
2278 
2279     void performReallyStop() {
2280         if (mChildFragmentManager != null) {
2281             mChildFragmentManager.dispatchReallyStop();
2282         }
2283         mState = ACTIVITY_CREATED;
2284         if (mLoadersStarted) {
2285             mLoadersStarted = false;
2286             if (!mCheckedForLoaderManager) {
2287                 mCheckedForLoaderManager = true;
2288                 mLoaderManager = mHost.getLoaderManager(mWho, mLoadersStarted, false);
2289             }
2290             if (mLoaderManager != null) {
2291                 if (mHost.getRetainLoaders()) {
2292                     mLoaderManager.doRetain();
2293                 } else {
2294                     mLoaderManager.doStop();
2295                 }
2296             }
2297         }
2298     }
2299 
2300     void performDestroyView() {
2301         if (mChildFragmentManager != null) {
2302             mChildFragmentManager.dispatchDestroyView();
2303         }
2304         mState = CREATED;
2305         mCalled = false;
2306         onDestroyView();
2307         if (!mCalled) {
2308             throw new SuperNotCalledException("Fragment " + this
2309                     + " did not call through to super.onDestroyView()");
2310         }
2311         if (mLoaderManager != null) {
2312             mLoaderManager.doReportNextStart();
2313         }
2314     }
2315 
2316     void performDestroy() {
2317         if (mChildFragmentManager != null) {
2318             mChildFragmentManager.dispatchDestroy();
2319         }
2320         mState = INITIALIZING;
2321         mCalled = false;
2322         onDestroy();
2323         if (!mCalled) {
2324             throw new SuperNotCalledException("Fragment " + this
2325                     + " did not call through to super.onDestroy()");
2326         }
2327         mChildFragmentManager = null;
2328     }
2329 
2330     void performDetach() {
2331         mCalled = false;
2332         onDetach();
2333         if (!mCalled) {
2334             throw new SuperNotCalledException("Fragment " + this
2335                     + " did not call through to super.onDetach()");
2336         }
2337 
2338         // Destroy the child FragmentManager if we still have it here.
2339         // We won't unless we're retaining our instance and if we do,
2340         // our child FragmentManager instance state will have already been saved.
2341         if (mChildFragmentManager != null) {
2342             if (!mRetaining) {
2343                 throw new IllegalStateException("Child FragmentManager of " + this + " was not "
2344                         + " destroyed and this fragment is not retaining instance");
2345             }
2346             mChildFragmentManager.dispatchDestroy();
2347             mChildFragmentManager = null;
2348         }
2349     }
2350 
2351 }
2352