Question

In my activity, on user’s request for preferences screen, I call:

startActivity(new Intent(this, Preferences.class));

Preferences class is defined like this:

public class Preferences extends PreferenceActivity implements OnSharedPreferenceChangeListener {
    ...
    public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
        ...
    }

}

I need to implement OnSharedPreferenceChangeListener in my Preferences class becase I want to be able to – for example – disable a preferences item based on a specific selection.
But I would need to implement it in my main Activity, to react to the preference changes.

Unfortunately onSharedPreferenceChanged() fires only in my Preferences class, and not in my main activity: how can I force it to be fired in bot activities?

Or – how can I manually call onSharedPreferenceChanged() in my main activity from onSharedPreferenceChanged() in Preferences activity?

Answer 1

in your main activity, you can register a listener for prefs changes:

SharedPreferences prefs = PreferenceManager
    .getDefaultSharedPreferences(this);
prefs.registerOnSharedPreferenceChangeListener(this);

and then you would implement SharedPreferences.OnSharedPreferenceChangeListener in your activity, with your own onSharedPreferenceChanged method.