1/* 2 * Copyright (C) 2009 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.backup.RestoreSession; 20import android.app.backup.IBackupManager; 21import android.app.backup.IRestoreSession; 22import android.content.Context; 23import android.os.RemoteException; 24import android.os.ServiceManager; 25import android.util.Log; 26 27/** 28 * The interface through which an application interacts with the Android backup service to 29 * request backup and restore operations. 30 * Applications instantiate it using the constructor and issue calls through that instance. 31 * <p> 32 * When an application has made changes to data which should be backed up, a 33 * call to {@link #dataChanged()} will notify the backup service. The system 34 * will then schedule a backup operation to occur in the near future. Repeated 35 * calls to {@link #dataChanged()} have no further effect until the backup 36 * operation actually occurs. 37 * <p> 38 * A backup or restore operation for your application begins when the system launches the 39 * {@link android.app.backup.BackupAgent} subclass you've declared in your manifest. See the 40 * documentation for {@link android.app.backup.BackupAgent} for a detailed description 41 * of how the operation then proceeds. 42 * <p> 43 * Several attributes affecting the operation of the backup and restore mechanism 44 * can be set on the <code><a 45 * href="{@docRoot}guide/topics/manifest/application-element.html"><application></a></code> 46 * tag in your application's AndroidManifest.xml file. 47 * 48 * @attr ref android.R.styleable#AndroidManifestApplication_allowBackup 49 * @attr ref android.R.styleable#AndroidManifestApplication_backupAgent 50 * @attr ref android.R.styleable#AndroidManifestApplication_killAfterRestore 51 * @attr ref android.R.styleable#AndroidManifestApplication_restoreAnyVersion 52 */ 53public class BackupManager { 54 private static final String TAG = "BackupManager"; 55 56 private Context mContext; 57 private static IBackupManager sService; 58 59 private static void checkServiceBinder() { 60 if (sService == null) { 61 sService = IBackupManager.Stub.asInterface( 62 ServiceManager.getService(Context.BACKUP_SERVICE)); 63 } 64 } 65 66 /** 67 * Constructs a BackupManager object through which the application can 68 * communicate with the Android backup system. 69 * 70 * @param context The {@link android.content.Context} that was provided when 71 * one of your application's {@link android.app.Activity Activities} 72 * was created. 73 */ 74 public BackupManager(Context context) { 75 mContext = context; 76 } 77 78 /** 79 * Notifies the Android backup system that your application wishes to back up 80 * new changes to its data. A backup operation using your application's 81 * {@link android.app.backup.BackupAgent} subclass will be scheduled when you 82 * call this method. 83 */ 84 public void dataChanged() { 85 checkServiceBinder(); 86 if (sService != null) { 87 try { 88 sService.dataChanged(mContext.getPackageName()); 89 } catch (RemoteException e) { 90 Log.d(TAG, "dataChanged() couldn't connect"); 91 } 92 } 93 } 94 95 /** 96 * Convenience method for callers who need to indicate that some other package 97 * needs a backup pass. This can be useful in the case of groups of packages 98 * that share a uid. 99 * <p> 100 * This method requires that the application hold the "android.permission.BACKUP" 101 * permission if the package named in the argument does not run under the same uid 102 * as the caller. 103 * 104 * @param packageName The package name identifying the application to back up. 105 */ 106 public static void dataChanged(String packageName) { 107 checkServiceBinder(); 108 if (sService != null) { 109 try { 110 sService.dataChanged(packageName); 111 } catch (RemoteException e) { 112 Log.d(TAG, "dataChanged(pkg) couldn't connect"); 113 } 114 } 115 } 116 117 /** 118 * Restore the calling application from backup. The data will be restored from the 119 * current backup dataset if the application has stored data there, or from 120 * the dataset used during the last full device setup operation if the current 121 * backup dataset has no matching data. If no backup data exists for this application 122 * in either source, a nonzero value will be returned. 123 * 124 * <p>If this method returns zero (meaning success), the OS will attempt to retrieve 125 * a backed-up dataset from the remote transport, instantiate the application's 126 * backup agent, and pass the dataset to the agent's 127 * {@link android.app.backup.BackupAgent#onRestore(BackupDataInput, int, android.os.ParcelFileDescriptor) onRestore()} 128 * method. 129 * 130 * @param observer The {@link RestoreObserver} to receive callbacks during the restore 131 * operation. This must not be null. 132 * 133 * @return Zero on success; nonzero on error. 134 */ 135 public int requestRestore(RestoreObserver observer) { 136 int result = -1; 137 checkServiceBinder(); 138 if (sService != null) { 139 RestoreSession session = null; 140 try { 141 String transport = sService.getCurrentTransport(); 142 IRestoreSession binder = sService.beginRestoreSession(transport); 143 session = new RestoreSession(mContext, binder); 144 result = session.restorePackage(mContext.getPackageName(), observer); 145 } catch (RemoteException e) { 146 Log.w(TAG, "restoreSelf() unable to contact service"); 147 } finally { 148 if (session != null) { 149 session.endRestoreSession(); 150 } 151 } 152 } 153 return result; 154 } 155 156 /** 157 * Begin the process of restoring data from backup. See the 158 * {@link android.app.backup.RestoreSession} class for documentation on that process. 159 * @hide 160 */ 161 public RestoreSession beginRestoreSession() { 162 RestoreSession session = null; 163 checkServiceBinder(); 164 if (sService != null) { 165 try { 166 String transport = sService.getCurrentTransport(); 167 IRestoreSession binder = sService.beginRestoreSession(transport); 168 session = new RestoreSession(mContext, binder); 169 } catch (RemoteException e) { 170 Log.w(TAG, "beginRestoreSession() couldn't connect"); 171 } 172 } 173 return session; 174 } 175} 176