How to play ringtone/alarm sound in Android

Question

You can simply play a setted ringtone with this:

Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification);
r.play();

If a user has never set an alarm on their phone, the TYPE_ALARM can return null. You can account for this with:

Uri alert = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM);

if(alert == null){
    // alert is null, using backup
    alert = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

    // I can't see this ever being null (as always have a default notification)
    // but just incase
    if(alert == null) {  
        // alert backup is null, using 2nd backup
        alert = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE);                
    }
}

This is the way I've done:

Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
MediaPlayer mp = MediaPlayer.create(getApplicationContext(), notification);
mp.start();

It is similar to markov00's way, but uses MediaPlayer instead of Ringtone which prevents interrupting other sounds, like music, that might already be playing in the background.

Your example is basically what I'm using. It never works on the emulator, however, because the emulator doesn't have any ringtones by default, and content://settings/system/ringtone doesn't resolve to anything playable. It works fine on my actual phone.

For the future googlers: use RingtoneManager.getActualDefaultRingtoneUri() instead of RingtoneManager.getDefaultUri(). According to its name, it would return the actual uri, so you can freely use it. From documentation of getActualDefaultRingtoneUri():

Gets the current default sound's Uri. This will give the actual sound Uri, instead of using this, most clients can use DEFAULT_RINGTONE_URI.

Meanwhile getDefaultUri() says this:

Returns the Uri for the default ringtone of a particular type. Rather than returning the actual ringtone's sound Uri, this will return the symbolic Uri which will resolved to the actual sound when played.