WallpaperBackupHelper.java revision 7f765cf588e37a70fa2a1d251aaa8e7b847801b6
1/* 2 * Copyright (C) 2010 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 17package android.app.backup; 18 19import android.app.WallpaperManager; 20import android.content.Context; 21import android.graphics.BitmapFactory; 22import android.os.ParcelFileDescriptor; 23import android.util.Slog; 24import android.view.Display; 25import android.view.WindowManager; 26 27import java.io.File; 28 29/** 30 * Helper for backing up / restoring wallpapers. Basically an AbsoluteFileBackupHelper, 31 * but with logic for deciding what to do with restored wallpaper images. 32 * 33 * @hide 34 */ 35public class WallpaperBackupHelper extends FileBackupHelperBase implements BackupHelper { 36 private static final String TAG = "WallpaperBackupHelper"; 37 private static final boolean DEBUG = true; 38 39 // This path must match what the WallpaperManagerService uses 40 private static final String WALLPAPER_IMAGE = "/data/data/com.android.settings/files/wallpaper"; 41 42 // Stage file - should be adjacent to the WALLPAPER_IMAGE location. The wallpapers 43 // will be saved to this file from the restore stream, then renamed to the proper 44 // location if it's deemed suitable. 45 private static final String STAGE_FILE = "/data/data/com.android.settings/files/wallpaper-tmp"; 46 47 Context mContext; 48 String[] mFiles; 49 double mDesiredMinWidth; 50 double mDesiredMinHeight; 51 52 /** 53 * Construct a helper for backing up / restoring the files at the given absolute locations 54 * within the file system. 55 * 56 * @param context 57 * @param files 58 */ 59 public WallpaperBackupHelper(Context context, String... files) { 60 super(context); 61 62 mContext = context; 63 mFiles = files; 64 65 WallpaperManager wpm; 66 wpm = (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE); 67 mDesiredMinWidth = (double) wpm.getDesiredMinimumWidth(); 68 mDesiredMinHeight = (double) wpm.getDesiredMinimumHeight(); 69 70 if (mDesiredMinWidth <= 0 || mDesiredMinHeight <= 0) { 71 WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE); 72 Display d = wm.getDefaultDisplay(); 73 mDesiredMinWidth = d.getWidth(); 74 mDesiredMinHeight = d.getHeight(); 75 } 76 77 if (DEBUG) { 78 Slog.d(TAG, "dmW=" + mDesiredMinWidth + " dmH=" + mDesiredMinHeight); 79 } 80 } 81 82 /** 83 * Based on oldState, determine which of the files from the application's data directory 84 * need to be backed up, write them to the data stream, and fill in newState with the 85 * state as it exists now. 86 */ 87 public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 88 ParcelFileDescriptor newState) { 89 performBackup_checked(oldState, data, newState, mFiles, mFiles); 90 } 91 92 /** 93 * Restore one absolute file entity from the restore stream. If we're restoring the 94 * magic wallpaper file, take specific action to determine whether it is suitable for 95 * the current device. 96 */ 97 public void restoreEntity(BackupDataInputStream data) { 98 final String key = data.getKey(); 99 if (isKeyInList(key, mFiles)) { 100 if (key.equals(WALLPAPER_IMAGE)) { 101 // restore the file to the stage for inspection 102 File f = new File(STAGE_FILE); 103 if (writeFile(f, data)) { 104 105 // Preflight the restored image's dimensions without loading it 106 BitmapFactory.Options options = new BitmapFactory.Options(); 107 options.inJustDecodeBounds = true; 108 BitmapFactory.decodeFile(STAGE_FILE, options); 109 110 if (DEBUG) Slog.d(TAG, "Restoring wallpaper image w=" + options.outWidth 111 + " h=" + options.outHeight); 112 113 // how much does the image differ from our preference? 114 double widthRatio = mDesiredMinWidth / options.outWidth; 115 double heightRatio = mDesiredMinHeight / options.outHeight; 116 if (widthRatio > 0.8 && widthRatio < 1.25 117 && heightRatio > 0.8 && heightRatio < 1.25) { 118 // sufficiently close to our resolution; go ahead and use it 119 if (DEBUG) Slog.d(TAG, "wallpaper dimension match; using"); 120 f.renameTo(new File(WALLPAPER_IMAGE)); 121 // TODO: spin a service to copy the restored image to sd/usb storage, 122 // since it does not exist anywhere other than the private wallpaper 123 // file. 124 } else { 125 if (DEBUG) Slog.d(TAG, "dimensions too far off: wr=" + widthRatio 126 + " hr=" + heightRatio); 127 f.delete(); 128 } 129 } 130 } else { 131 // Some other normal file; just decode it to its destination 132 File f = new File(key); 133 writeFile(f, data); 134 } 135 } 136 } 137} 138