Android Wear计时器开发(4)
这里会处理8个事件动作,其中5个负责控制计时器的状态(START、STOP、PAUSE、RESUME、RESET);一个负责更新Notification,剩下两个负责到45分钟唤醒后震动提示。
我们先从这几个控制状态开始:
public class MatchTimerReceiver extends BroadcastReceiver { public static final int MINUTE_MILLIS = 60000; private static final long DURATION = 45 * MINUTE_MILLIS; private static final Intent UPDATE_INTENT = new Intent(ACTION_UPDATE); private static final Intent ELAPSED_ALARM = new Intent(ACTION_ELAPSED_ALARM); private static final Intent FULL_TIME_ALARM = new Intent(ACTION_FULL_TIME_ALARM); private static final int REQUEST_UPDATE = 1; private static final int REQUEST_ELAPSED = 2; private static final int REQUEST_FULL_TIME = 3; public static void setUpdate(Context context) { context.sendBroadcast(UPDATE_INTENT); } . . . private void reset(MatchTimer timer) { timer.reset(); } private void resume(Context context, MatchTimer timer) { timer.resume(); long playedEnd = timer.getStartTime() + timer.getTotalStoppages() + DURATION; if (playedEnd > System.currentTimeMillis()) { setAlarm(context, REQUEST_FULL_TIME, FULL_TIME_ALARM, playedEnd); } } private void pause(Context context, MatchTimer timer) { timer.pause(); cancelAlarm(context, REQUEST_FULL_TIME, FULL_TIME_ALARM); long elapsedEnd = timer.getStartTime() + DURATION; if (!isAlarmSet(context, REQUEST_ELAPSED, ELAPSED_ALARM) && elapsedEnd > System.currentTimeMillis()) { setAlarm(context, REQUEST_ELAPSED, ELAPSED_ALARM, elapsedEnd); } } private void stop(Context context, MatchTimer timer) { timer.stop(); cancelAlarm(context, REQUEST_UPDATE, UPDATE_INTENT); cancelAlarm(context, REQUEST_ELAPSED, ELAPSED_ALARM); cancelAlarm(context, REQUEST_FULL_TIME, FULL_TIME_ALARM); } private void start(Context context, MatchTimer timer) { timer.start(); long elapsedEnd = timer.getStartTime() + DURATION; setRepeatingAlarm(context, REQUEST_UPDATE, UPDATE_INTENT); if (timer.getTotalStoppages() > 0 && !timer.isPaused()) { long playedEnd = timer.getStartTime() + timer.getTotalStoppages() + DURATION; if (playedEnd > System.currentTimeMillis()) { setAlarm(context, REQUEST_FULL_TIME, FULL_TIME_ALARM, playedEnd); } if (elapsedEnd > System.currentTimeMillis()) { setAlarm(context, REQUEST_ELAPSED, ELAPSED_ALARM, elapsedEnd); } } else { if (elapsedEnd > System.currentTimeMillis()) { setAlarm(context, REQUEST_FULL_TIME, FULL_TIME_ALARM, elapsedEnd); } } } . . . }
这些方法主要有两个功能:首先设置MatchTimer的状态,然后设置时间提醒的闹铃,改变参数就可以播放闹铃。这个功能还可以封装成一个工具方法,叫setUpdate()。这样外部也可以触发计时器的更新。
我们使用标准AlarmManager的方法来设置闹铃:
public class MatchTimerReceiver extends BroadcastReceiver { . . . public static final int MINUTE_MILLIS = 60000; . . . private void setRepeatingAlarm(Context context, int requestCode, Intent intent) { AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT); alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), MINUTE_MILLIS, pendingIntent); } private boolean isAlarmSet(Context context, int requestCode, Intent intent) { return PendingIntent.getBroadcast(context, requestCode, intent, PendingIntent.FLAG_NO_CREATE) != null; } private void setAlarm(Context context, int requestCode, Intent intent, long time) { AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, PendingIntent.FLAG_UPDATE_CURRENT); alarmManager.setExact(AlarmManager.RTC_WAKEUP, time, pendingIntent); } private void cancelAlarm(Context context, int requestCode, Intent intent) { PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, PendingIntent.FLAG_NO_CREATE); if (pendingIntent != null) { AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); alarmManager.cancel(pendingIntent); pendingIntent.cancel(); } } . . . }
这里值得讨论的是setRepeatingAlarm()这个方法。因为在Wear在实现方式上有点不一样。我们会在Start事件中每秒钟触发一次闹铃更新Notification动作,所以这里需要记录具体已经过去了多少分钟。正常来说我们会每隔60秒触发一次这个动作,但是在Wear上不能这么做。原因是——当设备在唤醒着的时候可以这样做,但是如果设备进入睡眠状态就需要重新计算下一分钟的边界值。这就需要异步更新部件,然后设备只需要每分钟唤醒一次。一分钟结束后在计时器需要更新状态的时候触发操作。
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