Android开发笔记（五十）定时器AlarmManager

import java.util.Timer;
import java.util.TimerTask;

import com.example.exmthread.R;

import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class AlarmActivity extends Activity implements OnClickListener {

	private TextView tv_alarm;
	private Button btn_timer;
	private Button btn_counter;
	private Button btn_alarm;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_alarm);

		btn_timer = (Button) findViewById(R.id.btn_timer);
		btn_counter = (Button) findViewById(R.id.btn_counter);
		btn_alarm = (Button) findViewById(R.id.btn_alarm);
		btn_timer.setOnClickListener(this);
		btn_counter.setOnClickListener(this);
		btn_alarm.setOnClickListener(this);

		tv_alarm = (TextView) findViewById(R.id.tv_alarm);
		ALARM_EVENT = getResources().getString(R.string.alarm_event);
	}

	@Override
	public void onClick(View v) {
		if (v.getId() == R.id.btn_timer) {
			if (mTimerTask == null) {
				mTimerTask = new MyTimerTask();
				Timer timer = new Timer();
				timer.schedule(mTimerTask, 50, 200);
				btn_timer.setText("停止Timer定时计数");
			} else {
				mTimerTask.cancel();
				mTimerTask = null;
				btn_timer.setText("开始Timer定时计数");
			}
		} else if (v.getId() == R.id.btn_counter) {
			if (mCounterTask == null) {
				mCounterTask = new MyCounter(8000, 1000);
				mCounterTask.start();
				btn_counter.setText("停止CountDownTimer定时计数");
			} else {
				mCounterTask.cancel();
				mCounterTask = null;
				btn_counter.setText("开始CountDownTimer定时计数");
			}
		} else if (v.getId() == R.id.btn_alarm) {
			if (alarmReceiver == null) {
				alarmReceiver = new AlarmReceiver();
				IntentFilter filter = new IntentFilter(ALARM_EVENT);
		        registerReceiver(alarmReceiver, filter);

				Intent intent = new Intent(ALARM_EVENT);
				PendingIntent pIntent = PendingIntent.getBroadcast(
						this, R.string.app_name, intent, PendingIntent.FLAG_UPDATE_CURRENT);
				AlarmManager alarmMgr = (AlarmManager)getSystemService(ALARM_SERVICE);
				alarmMgr.setRepeating(
						AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 200, pIntent);
				btn_alarm.setText("停止AlarmManager计数");
			} else {
		        unregisterReceiver(alarmReceiver);
		        alarmReceiver = null;
				btn_alarm.setText("开始AlarmManager计数");
			}
		}
	}

	private Handler mHandler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
			super.handleMessage(msg);
			if (msg.what == 0) {
				tv_alarm.setText("当前计数值为"+msg.arg1);
			} else if (msg.what == 1) {
				tv_alarm.setText("当前计数值为"+msg.arg1);
				btn_counter.setText("CountDownTimer计时结束，重新计时");
			}
		}
	};

	private MyCounter mCounterTask = null;
	private class MyCounter extends CountDownTimer {

		private int count;
		public MyCounter(long millisInFuture, long countDownInterval) {
			super(millisInFuture, countDownInterval);
			count = 0;
		}

		@Override
		public void onTick(long millisUntilFinished) {
			Message msg = mHandler.obtainMessage();
			msg.what = 0;
			msg.arg1 = count++;
			mHandler.sendMessage(msg);
		}

		@Override
		public void onFinish() {
			Message msg = mHandler.obtainMessage();
			msg.what = 1;
			msg.arg1 = count;
			mHandler.sendMessage(msg);
		}
		
	}

	private MyTimerTask mTimerTask = null;
	private class MyTimerTask extends TimerTask {
		private int count = 0;

		@Override
		public void run() {
			Message msg = mHandler.obtainMessage();
			msg.what = 0;
			msg.arg1 = count++;
			mHandler.sendMessage(msg);
		}
	}
	
	private String ALARM_EVENT = "";
	private int mCount = 0;
    private AlarmReceiver alarmReceiver = null;
    
    public class AlarmReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            if (intent != null) {
    			tv_alarm.setText("当前计数值为"+mCount++);
            }
        }
    }

}