Android中的Alarm

android中的定时任务。由AlarmManager对象进行管理
1.定时唤醒广播接受者
直接贴代码，在代码中说明
AlarmController.java

public class AlarmController extends Activity{
	private Toast mToast;
	private static final String TAG = "app";
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		setContentView(R.layout.alarm_controller);
		
		Button button = (Button)findViewById(R.id.one_shot);
		button.setOnClickListener(oneShotListener);
		button = (Button)findViewById(R.id.start_repeating);
		button.setOnClickListener(startRepeatingListener);
		button = (Button)findViewById(R.id.stop_repeating);
		button.setOnClickListener(stopRepeatingListener);
	}
	
	private OnClickListener oneShotListener = new OnClickListener() {	
		@Override
		public void onClick(View v) {	//只进行一次定时，不重复执行
			AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
			Calendar calendar = Calendar.getInstance();
			calendar.setTimeInMillis(System.currentTimeMillis());
			calendar.add(Calendar.SECOND, 30);	//设置30秒后执行
			
			/*
			 * 根据PendingIntent.getBroadcast
			 * 指明定时唤醒广播接收者
			 * */
			PendingIntent pending = PendingIntent.getBroadcast(AlarmController.this, 
					0, new Intent(AlarmController.this,OneShotAlarm.class), 0);
			am.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pending);  //表示在指定时间后执行
			
			if(mToast!=null){
				mToast.cancel();
			}
			mToast.makeText(AlarmController.this, "one_shot_scheduled", Toast.LENGTH_LONG).show();
		}
	};
	
	private OnClickListener startRepeatingListener = new OnClickListener() {
		@Override
		public void onClick(View v) {		//重复执行
			AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
			
			PendingIntent pend = PendingIntent.getBroadcast(AlarmController.this, 
					0, new Intent(AlarmController.this,RepeatingAlarm.class), 0);
			long triggerAtTime = SystemClock.elapsedRealtime();
			triggerAtTime +=15*1000;	//表示第一次执行15秒后
			am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,   
					triggerAtTime, 15*1000, pend);	//表示过15秒重复唤醒广播接受者
			if(mToast!=null){
				mToast.cancel();
			}
			mToast.makeText(AlarmController.this, "repeating_scheduled", Toast.LENGTH_LONG).show();
			
		}
	};
	
	private OnClickListener stopRepeatingListener = new OnClickListener() {
		@Override
		public void onClick(View v) {	//取消alarm
			AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
			
			PendingIntent pend = PendingIntent.getBroadcast(AlarmController.this, 
					0, new Intent(AlarmController.this,RepeatingAlarm.class), 0);
			am.cancel(pend);
			
			if(mToast!=null){
				mToast.cancel();
			}
			mToast.makeText(AlarmController.this, "stop_repeating_scheduled", Toast.LENGTH_LONG).show();
		}
	};

}

然后可以定期执行OneShotAlarm和RepeatingAlarm中的onRecevier中的内容

2.1.定时创建service
关键代码：

//注意此方法PendingIntent.getService()
PendingIntent pend = PendingIntent.getService(this, 0, 
				new Intent(this,AlarmService_Service.class), 0);
AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
long firstTime = SystemClock.elapsedRealtime();
am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime, 15*1000, pend);

完整例子：