I have a preference that controls whether or not my app plays a sound whenever the user clicks a button (which is done quite often, think of a calculator). Each time the user clicks the button the following method is called:
private void playButtonClickSound() {
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(parentActivity);
boolean sounds = sharedPrefs.getBoolean("prefSounds", false);
if (sounds) {
// blah
}
}
I was thinking that reading preferences might be an expensive operation (similar to an I/O operation because preferences are persisted) and that since the user clicks buttons so often it might be a bad idea to do it this way.
In general is it a bad idea to read/write preferences frequently? If so, might there be another way such as registering a preference change listener to get notified when a preference changes?
Frankly I do all of mine on the UI thread, whether or not I should, and I've never noticed a slight amount of hesitation even on slower devices. It's pretty damn quick. That said, it is I/O, so doing it asynchronously certainly wouldn't be a bad thing. For writes, if you're targeting API 9 and above, you can use apply()
instead of commit()
which does it asynchronously for you.
As for your question on a preference change listener, yes you can do that as well:
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
prefs.registerOnSharedPreferenceChangeListener(new OnSharedPreferenceChangeListener() {
@Override
public void onSharedPreferenceChanged(SharedPreferences preferences, String key) {
if("my_preference_key".equals(key) {
//Handle it here
}
}
}