android 定时启动\取消小例子

Intent intent = new Intent("cn.pocketdigi.update.alarm");
intent.setClass(this, AlarmReceiver.class);
PendingIntent pi=PendingIntent.getBroadcast(this, 0, intent,0);
//设置一个PendingIntent对象，发送广播
AlarmManager am=(AlarmManager)getSystemService(ALARM_SERVICE);
//获取AlarmManager对象
// am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+3500, pi);//只执行一次
am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+3500, 10000, pi); //重复执行

<receiver android:name=".AlarmReceiver">
<intent-filter>
<action android:name="cn.pocketdigi.update.alarm" />
</intent-filter>
</receiver>

public class AlarmReceiver extends BroadcastReceiver {
private static final String TAG = "AlarmReceiver";
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
Log.v(TAG, "收到广播");
// Intent it=new Intent(context,AlarmActivity.class);
// it.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
// context.startActivity(it);
//收到广播后启动Activity,简单起见，直接就跳到了设置alarm的Activity
//intent必须加上Intent.FLAG_ACTIVITY_NEW_TASK flag
}
}

Intent intent = new Intent("cn.pocketdigi.update.alarm");
intent.setClass(this, AlarmReceiver.class);
PendingIntent pi=PendingIntent.getBroadcast(this, 0, intent,0);
AlarmManager alarm=(AlarmManager)getSystemService(ALARM_SERVICE);
alarm.cancel(pi);

Intent intent =new Intent(Main.this, alarmreceiver.class);
intent.setAction("repeating");
PendingIntent sender=PendingIntent
.getBroadcast(Main.this, 0, intent, 0);
//开始时间
long firstime=SystemClock.elapsedRealtime();
AlarmManager am=(AlarmManager)getSystemService(ALARM_SERVICE);　　//5秒一个周期，不停的发送广播
am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP
, firstime, 5*1000, sender);