原因:ヌルポ === public void ring() { if (ring_tone == null) { Uri ringtone = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE); ring_tone = RingtoneManager.getRingtone(waffle_activity, ringtone); } if (ring_tone.isPlaying()) return; ring_tone.play(); } ===
修正