Android SharedPreferences with MODE_PRIVATE,MODE_WORLD_READABLE,MODE_WORLD_WRITABLE

Question

SharedPreferences in Android are local to an Application, and not shared between different applications. When I say

SharedPreferences preferences = getSharedPreferences(PREF_NAME, MODE_WORLD_READABLE); 

What does it signify to make this preferences MODE_WORLD_READABLE, MODE_WORLD_WRITABLE or MODE_PRIVATE?

Answer 1

getSharedPreferences(String name, int mode) is explained here

MODE_PRIVATE: File creation mode: the default mode, where the created file can only be accessed by the calling application (or all applications sharing the same user ID).  MODE_WORLD_READABLE: File creation mode: allow all other applications to have read access to the created file.  MODE_WORLD_WRITEABLE : File creation mode: allow all other applications to have write access to the created file. 

More info here

Edit As of API 17, the MODE_WORLD_READABLE and MODE_WORLD_WRITEABLE are deprecated:

This constant was deprecated in API level 17.
Creating world-readable files is very dangerous, and likely to cause security holes in applications. It is strongly discouraged; instead, applications should use more formal mechanism for interactions such as ContentProvider, BroadcastReceiver, and Service. There are no guarantees that this access mode will remain on a file, such as when it goes through a backup and restore.

Answer 2

Preferences are stored in the file system. The mode defines who has access to your app's preferences.

In simple terms:

• MODE_PRIVATE is the operating mode for the preferences. It is the default mode and means the created file will be accessed by only the calling application.
• In MODE_WORLD_READABLE other application can read the created file but can not modify it.
• In case of MODE_WORLD_WRITEABLE other applications also have write permissions for the created file.

The recommended way is to use by the default mode, without specifying the file name

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);