1 /* 2 * Copyright (C) 2013 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.hardware.display; 18 19 import android.content.Context; 20 import android.view.Display; 21 import android.view.WindowManager; 22 23 import java.util.WeakHashMap; 24 25 /** 26 * Helper for accessing features in {@link android.hardware.display.DisplayManager} 27 * introduced after API level 4 in a backwards compatible fashion. 28 */ 29 public abstract class DisplayManagerCompat { 30 private static final WeakHashMap<Context, DisplayManagerCompat> sInstances = 31 new WeakHashMap<Context, DisplayManagerCompat>(); 32 33 /** 34 * Display category: Presentation displays. 35 * <p> 36 * This category can be used to identify secondary displays that are suitable for 37 * use as presentation displays. 38 * </p> 39 * 40 * @see android.app.Presentation for information about presenting content 41 * on secondary displays. 42 * @see #getDisplays(String) 43 */ 44 public static final String DISPLAY_CATEGORY_PRESENTATION = 45 "android.hardware.display.category.PRESENTATION"; 46 DisplayManagerCompat()47 DisplayManagerCompat() { 48 } 49 50 /** 51 * Gets an instance of the display manager given the context. 52 */ getInstance(Context context)53 public static DisplayManagerCompat getInstance(Context context) { 54 synchronized (sInstances) { 55 DisplayManagerCompat instance = sInstances.get(context); 56 if (instance == null) { 57 final int version = android.os.Build.VERSION.SDK_INT; 58 if (version >= 17) { 59 instance = new JellybeanMr1Impl(context); 60 } else { 61 instance = new LegacyImpl(context); 62 } 63 sInstances.put(context, instance); 64 } 65 return instance; 66 } 67 } 68 69 /** 70 * Gets information about a logical display. 71 * 72 * The display metrics may be adjusted to provide compatibility 73 * for legacy applications. 74 * 75 * @param displayId The logical display id. 76 * @return The display object, or null if there is no valid display with the given id. 77 */ getDisplay(int displayId)78 public abstract Display getDisplay(int displayId); 79 80 /** 81 * Gets all currently valid logical displays. 82 * 83 * @return An array containing all displays. 84 */ getDisplays()85 public abstract Display[] getDisplays(); 86 87 /** 88 * Gets all currently valid logical displays of the specified category. 89 * <p> 90 * When there are multiple displays in a category the returned displays are sorted 91 * of preference. For example, if the requested category is 92 * {@link #DISPLAY_CATEGORY_PRESENTATION} and there are multiple presentation displays 93 * then the displays are sorted so that the first display in the returned array 94 * is the most preferred presentation display. The application may simply 95 * use the first display or allow the user to choose. 96 * </p> 97 * 98 * @param category The requested display category or null to return all displays. 99 * @return An array containing all displays sorted by order of preference. 100 * 101 * @see #DISPLAY_CATEGORY_PRESENTATION 102 */ getDisplays(String category)103 public abstract Display[] getDisplays(String category); 104 105 private static class LegacyImpl extends DisplayManagerCompat { 106 private final WindowManager mWindowManager; 107 LegacyImpl(Context context)108 public LegacyImpl(Context context) { 109 mWindowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE); 110 } 111 112 @Override getDisplay(int displayId)113 public Display getDisplay(int displayId) { 114 Display display = mWindowManager.getDefaultDisplay(); 115 if (display.getDisplayId() == displayId) { 116 return display; 117 } 118 return null; 119 } 120 121 @Override getDisplays()122 public Display[] getDisplays() { 123 return new Display[] { mWindowManager.getDefaultDisplay() }; 124 } 125 126 @Override getDisplays(String category)127 public Display[] getDisplays(String category) { 128 return category == null ? getDisplays() : new Display[0]; 129 } 130 } 131 132 private static class JellybeanMr1Impl extends DisplayManagerCompat { 133 private final Object mDisplayManagerObj; 134 JellybeanMr1Impl(Context context)135 public JellybeanMr1Impl(Context context) { 136 mDisplayManagerObj = DisplayManagerJellybeanMr1.getDisplayManager(context); 137 } 138 139 @Override getDisplay(int displayId)140 public Display getDisplay(int displayId) { 141 return DisplayManagerJellybeanMr1.getDisplay(mDisplayManagerObj, displayId); 142 } 143 144 @Override getDisplays()145 public Display[] getDisplays() { 146 return DisplayManagerJellybeanMr1.getDisplays(mDisplayManagerObj); 147 } 148 149 @Override getDisplays(String category)150 public Display[] getDisplays(String category) { 151 return DisplayManagerJellybeanMr1.getDisplays(mDisplayManagerObj, category); 152 } 153 } 154 } 155