getBoolean 返回 false

Question

I'm writing a program that needs to check for default preference settings and respond accordingly. The getBoolean method is always returning false even though R.xml.preferences has defaultValues set as true. I've tested preferences.contains(prefKey) and this has returned true.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_fullscreen);
    PreferenceManager.setDefaultValues(this, R.xml.preferences, true);

    populate();

}

public void populate() {
  SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);

  try {
    for (int x = 0; x < 9; x++) {
      if (preferences.getBoolean(prefKey, false)){
        for (int max = 0; max < 20; max++) {
          System.out.println("this ran"+ max + "times at" + i);
        }
      } else {
        for (int max = 0; max < 20; max++) {
          System.out.println("this Skipped"+ max + "times at" + i);
        }
      }
    }
  } catch (IOException ioe) {

  }
}

Answer 1

It is because of this

 if (preferences.getBoolean(prefKey, false))//your default value here is false

change to

if (preferences.getBoolean(prefKey, true))

Answer 2

Try clearing your prefs (in onCreate), before setting defaults:

PreferenceManager.getDefaultSharedPreferences(this).edit().clear().commit();
PreferenceManager.setDefaultValues(this, R.xml.preferences, true);

From the PreferenceManager.setDefaultValues() documentation:

Note: this will NOT reset preferences back to their default values. For that functionality, use getDefaultSharedPreferences(Context) and clear it followed by a call to this method with this parameter set to true.

Answer 3

Perhaps you have called setDefaultValues previously set prefKey to false. According to the PreferenceManager documentation

Note: this will NOT reset preferences back to their default values. For that functionality, use getDefaultSharedPreferences(Context) and clear it followed by a call to this method with this parameter set to true.