Using shared preferences between fragment and activity

Question

Im trying to use shared prefernces between my first activity and a fragment stationed on my second activity. The code shows what I have done so far but I am having problems getting the context. I also think what I am doing wont work so just want some quick help. Thanks

Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference

READ PREFS

 sharedPreferences =  getSharedPreferences("alexcz", MODE_PRIVATE);
 String drawableString = sharedPreferences.getString("PARTICLE_TYPE", "null")

WRITE PREF

 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_particle_type, container, false);

        white_blur = (ImageButton)view.findViewById(R.id.white_blur);
        green_blur = (ImageButton)view.findViewById(R.id.green_blur);
        orange_blur = (ImageButton)view.findViewById(R.id.orange_blur);
        pink_blur = (ImageButton)view.findViewById(R.id.pink_blur);
        yellow_blur = (ImageButton)view.findViewById(R.id.yellow_blur);
        blue_blur = (ImageButton)view.findViewById(R.id.blue_blur);

        main main = new main();
        Context context = main.getApplicationContext();

        sharedPref = context.getSharedPreferences("alexcz", main.MODE_PRIVATE);
        editor = sharedPref.edit();

 editor.putString("PARTICLE_TYPE", "white_blur");

        setOnClickListeners();
        return view;
    }

You're not actually writing anywhere. You're not using `editor`. — Vucko, Jul 16 '16 at 16:21

score 3 · Accepted Answer · edited May 23 '17 at 12:22

3

Never do this : main main = new main();. Instead do:

Context context = getActivity().getApplicationContext();

If you wish to access applicationContext inside of the fragment. When you initialize Android activities with a constructor, everything gets messed up, just don't do it. Refer to this question

edited May 23 '17 at 12:22

Community

1
1

answered Jul 16 '16 at 16:23

Vucko

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Nongthonbam Tonthoi · Answer 2 · 2016-07-16T16:39:25.673

0

Just replace these lines:

main main = new main();
Context context = main.getApplicationContext();
sharedPref = context.getSharedPreferences("alexcz", main.MODE_PRIVATE);

with:

sharedPref = getActivity().getSharedPreferences("alexcz", getActivity().MODE_PRIVATE);
editor = sharedPref.edit();

getActivity().MODE_PRIVATE will show a warning for accessing static member via instance.

edited Jul 16 '16 at 16:39

answered Jul 16 '16 at 16:34

Nongthonbam Tonthoi

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Using shared preferences between fragment and activity

2 Answers2