Android SharedPreference and database on app update

Question

Let's say I'm pushing a new version app to google play (17 to 18).

Is there a chance some devices have SharedPreference wiped out ? How about the local database ?

I think it could happen if some device somehow where to uninstall reinstall the app automatically rather than update.

Note : I've actually seen SharedPreferences getting wiped out on a few devices after update. Which is why I wonder why, how and it can happen to the Database as well.

Answer 1

in your SQLiteOpenHelper

    @Override
    public void onUpgrade(final SQLiteDatabase db, final int oldVersion, final int newVersion) {
      if (oldVersion < newVersion) {
        final Cursor cursor = db.rawQuery("select name from sqlite_master", null);
        if (cursor != null) {
          while (cursor.moveToNext()) {
            db.execSQL("delete from " + cursor.getString(0));
          }
          cursor.close();
        }
      }
    }