SharedPreferences Backup Not Working

Question

MyBackupAgentHelper.java

public class MyBackupAgentHelper extends BackupAgentHelper {

private static final String MESSAGE_DB_FILE_BACKUP_KEY = "MESSAGE_DB_FILE_BACKUP_KEY";
private static final String DEFAULT_SHARED_PREFRERNCES_KEY = "DEFAULT_SHARED_PREFRERNCES_KEY";

@Override
public void onCreate() {
    super.onCreate();

    LogUtil.pd();

    File file = MessageDao.getSingleton(this).getSQLite().getFile();
    if (file == null) {
        LogUtil.w("Messsage DB File is NULL !");
    } else {
        LogUtil.i("Messsage DB File: "+file.getAbsolutePath());
        FileBackupHelper backupHelper = new FileBackupHelper(this, file.getName());
        addHelper(MESSAGE_DB_FILE_BACKUP_KEY, backupHelper);
    }

    String prefName = getDefaultSharedPreferencesName(this); // It return "my.package.name_preferences"
    LogUtil.i("Default Shared Preferences Name: "+prefName);
    SharedPreferencesBackupHelper backupHelper = new SharedPreferencesBackupHelper(this, prefName);
    addHelper(DEFAULT_SHARED_PREFRERNCES_KEY, backupHelper);
}

Log Cat

03-26 10:11:02.361: I/MyPackage(3540): Messsage DB File: /data/data/my.package.name/files/db.sqlite
03-26 10:11:02.361: I/MyPackage(3540): Default Shared Preferences Name: my.package.name_preferences

Data Directory File Tree (data/data/my.package.name)

03-26 10:09:22.291: I/MyPackage(3540): my.package.name
03-26 10:09:22.291: I/MyPackage(3540): -shared_prefs
03-26 10:09:22.291: I/MyPackage(3540): --my.package.name_preferences.xml
03-26 10:09:22.291: I/MyPackage(3540): -files
03-26 10:09:22.291: I/MyPackage(3540): --db.sqlite
03-26 10:09:22.291: I/MyPackage(3540): -lib

And I forced to backup via adb shell, deleted my app, and reinstalled my app.

I checked backup & restore db.sqlite file (It works fine.)

But default SharedPreferences is not restored or backuped.

How can I backup & restore default SharedPreferences?

Answer 1

You need to set the permission of SharedPreference to at least MODE_WORLD_READABLE, by default it is created in MODE_PRIVATE.

Click to read API docs for SharedPreference modes on developer.android.com!

You can backup SharedPreference if it is not MODE_PRIVATE using adb backup command.