1 /* 2 * Copyright (C) 2006 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.widget; 18 19 import android.content.Context; 20 import android.util.AttributeSet; 21 import android.view.View; 22 import android.view.ViewGroup; 23 import android.view.accessibility.AccessibilityEvent; 24 import android.view.accessibility.AccessibilityNodeInfo; 25 26 /** 27 * {@link ViewAnimator} that switches between two views, and has a factory 28 * from which these views are created. You can either use the factory to 29 * create the views, or add them yourself. A ViewSwitcher can only have two 30 * child views, of which only one is shown at a time. 31 */ 32 public class ViewSwitcher extends ViewAnimator { 33 /** 34 * The factory used to create the two children. 35 */ 36 ViewFactory mFactory; 37 38 /** 39 * Creates a new empty ViewSwitcher. 40 * 41 * @param context the application's environment 42 */ ViewSwitcher(Context context)43 public ViewSwitcher(Context context) { 44 super(context); 45 } 46 47 /** 48 * Creates a new empty ViewSwitcher for the given context and with the 49 * specified set attributes. 50 * 51 * @param context the application environment 52 * @param attrs a collection of attributes 53 */ ViewSwitcher(Context context, AttributeSet attrs)54 public ViewSwitcher(Context context, AttributeSet attrs) { 55 super(context, attrs); 56 } 57 58 /** 59 * {@inheritDoc} 60 * 61 * @throws IllegalStateException if this switcher already contains two children 62 */ 63 @Override addView(View child, int index, ViewGroup.LayoutParams params)64 public void addView(View child, int index, ViewGroup.LayoutParams params) { 65 if (getChildCount() >= 2) { 66 throw new IllegalStateException("Can't add more than 2 views to a ViewSwitcher"); 67 } 68 super.addView(child, index, params); 69 } 70 71 @Override onInitializeAccessibilityEvent(AccessibilityEvent event)72 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 73 super.onInitializeAccessibilityEvent(event); 74 event.setClassName(ViewSwitcher.class.getName()); 75 } 76 77 @Override onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)78 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 79 super.onInitializeAccessibilityNodeInfo(info); 80 info.setClassName(ViewSwitcher.class.getName()); 81 } 82 83 /** 84 * Returns the next view to be displayed. 85 * 86 * @return the view that will be displayed after the next views flip. 87 */ getNextView()88 public View getNextView() { 89 int which = mWhichChild == 0 ? 1 : 0; 90 return getChildAt(which); 91 } 92 obtainView()93 private View obtainView() { 94 View child = mFactory.makeView(); 95 LayoutParams lp = (LayoutParams) child.getLayoutParams(); 96 if (lp == null) { 97 lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT); 98 } 99 addView(child, lp); 100 return child; 101 } 102 103 /** 104 * Sets the factory used to create the two views between which the 105 * ViewSwitcher will flip. Instead of using a factory, you can call 106 * {@link #addView(android.view.View, int, android.view.ViewGroup.LayoutParams)} 107 * twice. 108 * 109 * @param factory the view factory used to generate the switcher's content 110 */ setFactory(ViewFactory factory)111 public void setFactory(ViewFactory factory) { 112 mFactory = factory; 113 obtainView(); 114 obtainView(); 115 } 116 117 /** 118 * Reset the ViewSwitcher to hide all of the existing views and to make it 119 * think that the first time animation has not yet played. 120 */ reset()121 public void reset() { 122 mFirstTime = true; 123 View v; 124 v = getChildAt(0); 125 if (v != null) { 126 v.setVisibility(View.GONE); 127 } 128 v = getChildAt(1); 129 if (v != null) { 130 v.setVisibility(View.GONE); 131 } 132 } 133 134 /** 135 * Creates views in a ViewSwitcher. 136 */ 137 public interface ViewFactory { 138 /** 139 * Creates a new {@link android.view.View} to be added in a 140 * {@link android.widget.ViewSwitcher}. 141 * 142 * @return a {@link android.view.View} 143 */ makeView()144 View makeView(); 145 } 146 } 147 148