Android-从活动到广播接收器获取首选项

Question

I'm developing an Android app but I have a problem. When I try to get a saved preference from my Activity and use it in a BroadcastReceiver , it tells me that string I'm looking for doesn't exist.

This is how I save the preference in the Activity:

private void SavePreferences(String key, String value) {                         
  SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
  SharedPreferences.Editor editor = sharedPreferences.edit();
  editor.putString(key, value);
  editor.commit();
}

And this is how I try to get the preference in BroadcastReceiver :

String pref = PreferenceManager.getDefaultSharedPreferences(context)
  .getString("MEM1", "Does not exist");

Where MEM1 is the string I saved before.

My problem is that when I read pref , I'm getting the default value of Does not exist , instead of my preference value ( MEM1 ). Can someone point me to where I'm going wrong?

Answer 1

Activity.getPreferences(mode);

returns an instance of SharedPreferences that is specific to that Activity (as in, the XML file backing it will be named the same as the activity), while default shared preferences is specific to the application (the XML name will be based on your package name).

Either provide a custom file name every time you retrieve SharedPreferences, or stick to the default.

Answer 2

You Should Use..

private void SavePreferences(String key, String value){

        SharedPreferences sharedPreferences = getPreferences("my_prefs", MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
       }

And Then

String pref = getSharedPreferences("my_prefs", MODE_PRIVATE).getString("MEM1", "Does not exist");

Also Make Sure Your Key Is Correct.