简单播放系统提示音 android

//Uri alert = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_ALARM);
//alert = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
//alert = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE);




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