alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Android example source code file (BackupManager.java)

This example Android source code file (BackupManager.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, app, application, backupmanager, content, context, ibackupmanager, irestoresession, os, remoteexception, restoresession, string, tag, utilities

The BackupManager.java Android example source code

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.app.backup;

import android.app.backup.RestoreSession;
import android.app.backup.IBackupManager;
import android.app.backup.IRestoreSession;
import android.content.Context;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.Log;

/**
 * The interface through which an application interacts with the Android backup service to
 * request backup and restore operations.
 * Applications instantiate it using the constructor and issue calls through that instance.
 * <p>
 * When an application has made changes to data which should be backed up, a
 * call to {@link #dataChanged()} will notify the backup service. The system
 * will then schedule a backup operation to occur in the near future. Repeated
 * calls to {@link #dataChanged()} have no further effect until the backup
 * operation actually occurs.
 * <p>
 * A backup or restore operation for your application begins when the system launches the
 * {@link android.app.backup.BackupAgent} subclass you've declared in your manifest. See the
 * documentation for {@link android.app.backup.BackupAgent} for a detailed description
 * of how the operation then proceeds.
 * <p>
 * Several attributes affecting the operation of the backup and restore mechanism
 * can be set on the <code>
 * tag in your application's AndroidManifest.xml file.
 *
 * @attr ref android.R.styleable#AndroidManifestApplication_allowBackup
 * @attr ref android.R.styleable#AndroidManifestApplication_backupAgent
 * @attr ref android.R.styleable#AndroidManifestApplication_killAfterRestore
 * @attr ref android.R.styleable#AndroidManifestApplication_restoreAnyVersion
 */
public class BackupManager {
    private static final String TAG = "BackupManager";

    private Context mContext;
    private static IBackupManager sService;

    private static void checkServiceBinder() {
        if (sService == null) {
            sService = IBackupManager.Stub.asInterface(
                    ServiceManager.getService(Context.BACKUP_SERVICE));
        }
    }

    /**
     * Constructs a BackupManager object through which the application can
     * communicate with the Android backup system.
     *
     * @param context The {@link android.content.Context} that was provided when
     *                one of your application's {@link android.app.Activity Activities}
     *                was created.
     */
    public BackupManager(Context context) {
        mContext = context;
    }

    /**
     * Notifies the Android backup system that your application wishes to back up
     * new changes to its data.  A backup operation using your application's
     * {@link android.app.backup.BackupAgent} subclass will be scheduled when you
     * call this method.
     */
    public void dataChanged() {
        checkServiceBinder();
        if (sService != null) {
            try {
                sService.dataChanged(mContext.getPackageName());
            } catch (RemoteException e) {
                Log.d(TAG, "dataChanged() couldn't connect");
            }
        }
    }

    /**
     * Convenience method for callers who need to indicate that some other package
     * needs a backup pass.  This can be useful in the case of groups of packages
     * that share a uid.
     * <p>
     * This method requires that the application hold the "android.permission.BACKUP"
     * permission if the package named in the argument does not run under the same uid
     * as the caller.
     *
     * @param packageName The package name identifying the application to back up.
     */
    public static void dataChanged(String packageName) {
        checkServiceBinder();
        if (sService != null) {
            try {
                sService.dataChanged(packageName);
            } catch (RemoteException e) {
                Log.d(TAG, "dataChanged(pkg) couldn't connect");
            }
        }
    }

    /**
     * Restore the calling application from backup.  The data will be restored from the
     * current backup dataset if the application has stored data there, or from
     * the dataset used during the last full device setup operation if the current
     * backup dataset has no matching data.  If no backup data exists for this application
     * in either source, a nonzero value will be returned.
     *
     * <p>If this method returns zero (meaning success), the OS will attempt to retrieve
     * a backed-up dataset from the remote transport, instantiate the application's
     * backup agent, and pass the dataset to the agent's
     * {@link android.app.backup.BackupAgent#onRestore(BackupDataInput, int, android.os.ParcelFileDescriptor) onRestore()}
     * method.
     *
     * @param observer The {@link RestoreObserver} to receive callbacks during the restore
     * operation. This must not be null.
     *
     * @return Zero on success; nonzero on error.
     */
    public int requestRestore(RestoreObserver observer) {
        int result = -1;
        checkServiceBinder();
        if (sService != null) {
            RestoreSession session = null;
            try {
                String transport = sService.getCurrentTransport();
                IRestoreSession binder = sService.beginRestoreSession(transport);
                session = new RestoreSession(mContext, binder);
                result = session.restorePackage(mContext.getPackageName(), observer);
            } catch (RemoteException e) {
                Log.w(TAG, "restoreSelf() unable to contact service");
            } finally {
                if (session != null) {
                    session.endRestoreSession();
                }
            }
        }
        return result;
    }

    /**
     * Begin the process of restoring data from backup.  See the
     * {@link android.app.backup.RestoreSession} class for documentation on that process.
     * @hide
     */
    public RestoreSession beginRestoreSession() {
        RestoreSession session = null;
        checkServiceBinder();
        if (sService != null) {
            try {
                String transport = sService.getCurrentTransport();
                IRestoreSession binder = sService.beginRestoreSession(transport);
                session = new RestoreSession(mContext, binder);
            } catch (RemoteException e) {
                Log.w(TAG, "beginRestoreSession() couldn't connect");
            }
        }
        return session;
    }
}
... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.