Question

I have a PreferenceScreen containing only CheckBoxPreferences (categories to select). I need an option to check/uncheck all of them. I have the following code that does the job but there is one problem: checkboxes on the screen are not updated – I’d need to call some invalidate on the view or something.

Here is my present code:

    private void checkAll() {
        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this);
        SharedPreferences.Editor editor = settings.edit();
        @SuppressWarnings("unchecked")
        Map<String, Boolean> categories = (Map<String, Boolean>) settings.getAll();
        for(String s : categories.keySet()) {
            editor.putBoolean(s, true);
        }
        editor.commit();
    }

    private void uncheckAll() {
        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this);
        SharedPreferences.Editor editor = settings.edit();
        @SuppressWarnings("unchecked")
        Map<String, Boolean> categories = (Map<String, Boolean>) settings.getAll();
        for(String s : categories.keySet()) {
            editor.putBoolean(s, false);
        }
        editor.commit();
        this.restart();
    }

This code works fine but I’d need to refresh the view somehow to see the result imediatelly (not just after closing and re-starting the settings activity).

Thank You all for any advice!

Answer 1

That’s because you’re not actually grabbing the preference objects, just the actual values. Try this in your for loops:

 boolean theValue = param;
 for(String s : categories.keySet()) {
    Preference pref = findPreference(s);
    if (pref instanceof CheckBoxPreference) {
      CheckBoxPreference check = (CheckBoxPreference)pref;
      check.setChecked(theValue);
    }
  }

I think you can omit calling the editor and committing, as the setChecked() will do that for you.

Check this out as well.