一次性闹钟
// When the alarm goes off, we want to broadcast an Intent to our
// BroadcastReceiver. Here we make an Intent with an explicit class
// name to have our own receiver (which has been published in
// AndroidManifest.xml) instantiated and called, and then create an
// IntentSender to have the intent executed as a broadcast.
Intent intent = new Intent(AlarmController.this, OneShotAlarm.class);
PendingIntent sender \= PendingIntent.getBroadcast(
AlarmController.this, 0, intent, 0);
// We want the alarm to go off 10 seconds from now.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 10);
// Schedule the alarm!
AlarmManager am = (AlarmManager) getSystemService(ALARM\_SERVICE);
am.set(AlarmManager.RTC\_WAKEUP, calendar.getTimeInMillis(), sender);
重复闹钟
闹钟设置：
// When the alarm goes off, we want to broadcast an Intent to our
// BroadcastReceiver. Here we make an Intent with an explicit class
// name to have our own receiver (which has been published in
// AndroidManifest.xml) instantiated and called, and then create an
// IntentSender to have the intent executed as a broadcast.
// Note that unlike above, this IntentSender is configured to
// allow itself to be sent multiple times.
Intent intent = new Intent(AlarmController.this,
RepeatingAlarm.class);
PendingIntent sender \= PendingIntent.getBroadcast(
AlarmController.this, 0, intent, 0);
// We want the alarm to go off 10 seconds from now.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 10);
// Schedule the alarm!
AlarmManager am = (AlarmManager) getSystemService(ALARM\_SERVICE);
am.setRepeating(AlarmManager.RTC\_WAKEUP,
calendar.getTimeInMillis(), 10 \* 1000, sender);
闹钟取消：
// Create the same intent, and thus a matching IntentSender, for
// the one that was scheduled.
Intent intent = new Intent(AlarmController.this,
RepeatingAlarm.class);
PendingIntent sender \= PendingIntent.getBroadcast(
AlarmController.this, 0, intent, 0);
// And cancel the alarm.
AlarmManager am = (AlarmManager) getSystemService(ALARM\_SERVICE);
am.cancel(sender);
AlarmManager说明
AlarmManager这个类提供对系统闹钟服务的访问接口。
对它的获取是通过系统服务：
Context.getSystemService(Context.ALARM_SERVICE)。
相关方法说明：
cancel(PendingIntent operation)方法将会取消Intent匹配的任何闹钟。
关于Intent的匹配，查看filterEquals(Intent other)方法的说明可知，两个Intent从intent resolution(filtering)(Intent决议或过滤)的角度来看是一致的，即认为两个Intent相等。即是说，Intent的action,data,type,class,categories是相同的，其他的数据都不在比较范围之内。
set(int type, long triggerAtMillis, PendingIntent operation)方法将会设置一个闹钟。
注意：对于计时操作，可能使用Handler更加有效率和简单。
设置闹钟的时候注意：
1.如果声明的triggerAtMillis是一个过去的时间，闹钟将会立即被触发。
2.如果已经有一个相同intent的闹钟被设置过了，那么前一个闹钟将会取消，被新设置的闹钟所代替。
注意这里说的intent相同指的都是Intent在 filterEquals(Intent)的定义下匹配。
闹钟是一个广播，接收器需要自己定义和注册，注册使用动态注册( registerReceiver(BroadcastReceiver, IntentFilter) )或者静态注册( tag in an AndroidManifest.xml file)都可以。
setRepeating(int type, long triggerAtMillis, long intervalMillis, PendingIntent operation)方法将会设置一个重复性的闹钟。
比set方法多了一个间隔参数。
type的类型是四种：
ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC, RTC_WAKEUP.
区分的是时间标准和是否在睡眠状态下唤醒设备。
具体查看官方文档吧不再详细解释啦。
实例
比如要设置一个每晚21:30唤醒的重复闹钟：
private static final int INTERVAL = 1000 \* 60 \* 60 \* 24;// 24h
//...
Intent intent \= new Intent(context, RequestAlarmReceiver.class);
PendingIntent sender \= PendingIntent.getBroadcast(context,
REQUEST\_CODE, intent, PendingIntent.FLAG\_CANCEL\_CURRENT);
// Schedule the alarm!
AlarmManager am = (AlarmManager) context
.getSystemService(Context.ALARM\_SERVICE);
Calendar calendar \= Calendar.getInstance();
calendar.set(Calendar.HOUR\_OF\_DAY, 21);
calendar.set(Calendar.MINUTE, 30);
calendar.set(Calendar.SECOND, 10);
calendar.set(Calendar.MILLISECOND, 0);
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