Question

I’ve created an Android live wallpaper and i’m trying to let a user choose an image from their phone and apply it as a background image, but when I launch the activity that start the intent to pick the images, my shared preferences don’t seem to save properly.

Below is my onCreate method of the activity I start when the users presses the preference button, and the onActivityResult which gets the path of the image on the device (all that seems to work). The println after I commit the preferences prints out nothing.

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
    photoPickerIntent.setType("image/*");
    startActivityForResult(photoPickerIntent, SELECT_PICTURE);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE) {
            Uri selectedImageUri = data.getData();
            selectedImagePath = getPath(selectedImageUri);

            preferences = getApplicationContext().getSharedPreferences(PREFERENCES_NAME, 0);
            preferences.edit().putString(SETTINGS_BACKGROUND_IMAGE, "okok");
            preferences.edit().commit();

            System.out.println("Image" + preferences.getString(SETTINGS_BACKGROUND_IMAGE, ""));
        }
    }

    finish();
}

Answer 1

From the documentation:

Create a new Editor for these preferences, through which you can make
modifications to the data in the preferences and atomically commit
those changes back to the SharedPreferences object.

Since that’s a new Editor instance, your code should be more like this:

preferences = getApplicationContext().getSharedPreferences(PREFERENCES_NAME, 0);
SharedPreferences.Editor editor = preferences.edit();
editor.putString(SETTINGS_BACKGROUND_IMAGE, "okok");
editor.apply();