1 /* 2 * Copyright (C) 2015 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.v7.preference; 18 19 import android.content.Context; 20 import android.util.AttributeSet; 21 22 /** 23 * Represents a top-level {@link Preference} that 24 * is the root of a Preference hierarchy. A {@link PreferenceFragmentCompat} 25 * points to an instance of this class to show the preferences. To instantiate 26 * this class, use {@link PreferenceManager#createPreferenceScreen(android.content.Context)}. 27 * <ul> 28 * This class can appear in two places: 29 * <li> When a {@link PreferenceFragmentCompat} points to this, it is used as the root 30 * and is not shown (only the contained preferences are shown). 31 * <li> When it appears inside another preference hierarchy, it is shown and 32 * serves as the gateway to another screen of preferences (either by showing 33 * another screen of preferences as a {@link android.app.Dialog} or via a 34 * {@link android.content.Context#startActivity(android.content.Intent)} from the 35 * {@link Preference#getIntent()}). The children of this {@link PreferenceScreen} 36 * are NOT shown in the screen that this {@link PreferenceScreen} is shown in. 37 * Instead, a separate screen will be shown when this preference is clicked. 38 * </ul> 39 * <p>Here's an example XML layout of a PreferenceScreen:</p> 40 * <pre> 41 <PreferenceScreen 42 xmlns:android="http://schemas.android.com/apk/res/android" 43 android:key="first_preferencescreen"> 44 <CheckBoxPreference 45 android:key="wifi enabled" 46 android:title="WiFi" /> 47 <PreferenceScreen 48 android:key="second_preferencescreen" 49 android:title="WiFi settings"> 50 <CheckBoxPreference 51 android:key="prefer wifi" 52 android:title="Prefer WiFi" /> 53 ... other preferences here ... 54 </PreferenceScreen> 55 </PreferenceScreen> </pre> 56 * <p> 57 * In this example, the "first_preferencescreen" will be used as the root of the 58 * hierarchy and given to a {@link android.support.v14.preference.PreferenceFragment} 59 * or {@link PreferenceFragmentCompat}. 60 * The first screen will 61 * show preferences "WiFi" (which can be used to quickly enable/disable WiFi) 62 * and "WiFi settings". The "WiFi settings" is the "second_preferencescreen" and when 63 * clicked will show another screen of preferences such as "Prefer WiFi" (and 64 * the other preferences that are children of the "second_preferencescreen" tag). 65 * 66 * <div class="special reference"> 67 * <h3>Developer Guides</h3> 68 * <p>For information about building a settings UI with Preferences, 69 * read the <a href="{@docRoot}guide/topics/ui/settings.html">Settings</a> 70 * guide.</p> 71 * </div> 72 * 73 * @see PreferenceCategory 74 */ 75 public final class PreferenceScreen extends PreferenceGroup { 76 77 /** 78 * Do NOT use this constructor, use {@link PreferenceManager#createPreferenceScreen(Context)}. 79 * @hide- 80 */ PreferenceScreen(Context context, AttributeSet attrs)81 public PreferenceScreen(Context context, AttributeSet attrs) { 82 super(context, attrs, R.attr.preferenceScreenStyle); 83 } 84 85 @Override onClick()86 protected void onClick() { 87 if (getIntent() != null || getFragment() != null || getPreferenceCount() == 0) { 88 return; 89 } 90 final PreferenceManager.OnNavigateToScreenListener listener = 91 getPreferenceManager().getOnNavigateToScreenListener(); 92 if (listener != null) { 93 listener.onNavigateToScreen(this); 94 } 95 } 96 97 @Override isOnSameScreenAsChildren()98 protected boolean isOnSameScreenAsChildren() { 99 return false; 100 } 101 102 } 103