Android cloud - Backup Manager vs Drive

Question

I'm developing an application and I would like to implement a feature where it would be possible to share, lets say, favourites, bookmarks, etc, between the same user devices. So, I want to achieve something like iCloud.

I came across 2 possible ideas: Backup Manager and Google Drive. I think Backup Manager is the simplest solution and would fit my needs but maybe I'm wrong:

Note: The backup service is not designed for synchronizing application data with other clients or saving data that you'd like to access during the normal application lifecycle. You cannot read or write backup data on demand and cannot access it in any way other than through the APIs provided by the Backup Manager.

Note: The backup transport provided by Android Backup Service is not guaranteed to be available on all Android-powered devices that support backup. Some devices might support backup using a different transport, some devices might not support backup at all, and there is no way for your application to know what transport is used on the device.

Since I'm storing this information in SharedPreferences I started my implementation by extending BackupAgentHelper as Google advises (http://developer.android.com/guide/topics/data/backup.html#BackupAgentHelper).

...each time the user changes some data, your app should call dataChanged(), which adds a backup request to the Backup Manager queue.

So, each time I change data, save or remove a bookmark for example, I call:

BackupManager.dataChanged(C.PROJECT_PATH);

When my applications starts I call:

contentBackupManager.requestRestore(new RestoreObserver() {})

Everything is setup and AndroidManifest.xml too.

Unfortunately requestRestore is returning != 0 (error) and my BackupAngent (extends BackupAgentHelper) onBackup and onRestore aren't being called (onCreate is). But, once again:

A backup request does not result in an immediate call to your onBackup() method. Instead, the Backup Manager waits for an appropriate time, then performs backup for all applications that have requested a backup since the last backup was performed.

Does this means I'll only find my answer in Google Drive?

Answer 1

You are correct that you shouldn't use BackupManager for this. You will need to use a third-party service that will hold your exact type of data. So you can either:

• Use a service like Google Drive or Dropbox that provides an API where you can upload (and download) any type of file, and store your data in a format of your choosing (XML / JSON / binary). The upsides here are that:
  • You don't need a server-side app for data storage, so less dev effort
  • The user owns their own data, which can be important for some users
• Write some custom server-side code that will provide an API specific to your app. You can use Google App Engine for this. Obviously, the downsides are increased development effort and potential bills from appengine if you get a lot of users. However, you have multiple advantages as well if you go this route:
  • You don't waste space on the user's Drive or Dropbox account,
  • Users don't like to enter their Drive / Dropbox credentials in 3rd party apps,
  • You get to use nifty features such as GCM,
  • You store your data in an actual database, so you can structure it as you wish, and you also own it.

You pick :)