播放一个声音
// Do the common stuff when starting the alarm. private void startAlarm(MediaPlayer player) throws java.io.IOException, IllegalArgumentException, IllegalStateException { final AudioManager audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE); // do not play alarms if stream volume is 0 // (typically because ringer mode is silent). if (audioManager.getStreamVolume(AudioManager.STREAM_ALARM) != 0) { player.setAudioStreamType(AudioManager.STREAM_ALARM); player.setLooping(true); player.prepare(); player.start(); } } private void setDataSourceFromResource(Resources resources, MediaPlayer player, int res) throws java.io.IOException { AssetFileDescriptor afd = resources.openRawResourceFd(res); if (afd != null) { player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength()); afd.close(); } }private static final float IN_CALL_VOLUME = 0.125f; // Check if we are in a call. If we are, use the in-call alarm // resource at a low volume to not disrupt the call. if (mTelephonyManager.getCallState() != TelephonyManager.CALL_STATE_IDLE) { Log.v("Using the in-call alarm"); mMediaPlayer.setVolume(IN_CALL_VOLUME, IN_CALL_VOLUME); setDataSourceFromResource(getResources(), mMediaPlayer, R.raw.in_call_alarm); } else { mMediaPlayer.setDataSource(this, alert); } startAlarm(mMediaPlayer);?