Seems like those are different from eachother:
http://developer.android.com/guide/topics/manifest/application-element.html
<application android:allowTaskReparenting=["true" | "false"]
android:allowBackup=["true" | "false"]
android:backupAgent="string"
And:
http://developer.android.com/reference/android/app/backup/BackupAgent.html
Provides the central interface between an application and Android's
data backup infrastructure. An application that wishes to participate
in the backup and restore mechanism will declare a subclass of
BackupAgent, implement the onBackup() and onRestore() methods, and
provide the name of its backup agent class in its AndroidManifest.xml
file via the <application>
tag's android:backupAgent attribute.
And you need to add this in your ApplicationTAG -> Manifest
:
android:backupAgent
Also, you may want to take a look:
Most applications shouldn't need to extend the BackupAgent class directly, but should instead extend BackupAgentHelper to take advantage of the built-in helper classes that automatically backup and restore your files. However, you might want to extend BackupAgent directly if you need to:
Version your data format. For instance, if you anticipate the need to
revise the format in which you write your application data, you can
build a backup agent to cross-check your application version during a
restore operation and perform any necessary compatibility work if the
version on the device is different than that of the backup data. For
more information, see Checking the Restore Data Version.
Instead of backing up an entire file, you can specify the portions of
data the should be backed up and how each portion is then restored to
the device. (This can also help you manage different versions,
because you read and write your data as unique entities, rather than
complete files.)
- Back up data in a database. If you have an SQLite database that you
want to restore when the user re-installs your application, you need
to build a custom BackupAgent that reads the appropriate data during
a backup operation, then create your table and insert the data during
a restore operation.