[置顶] 学习如何每隔一段时间定时重复执行任务

学习了定时执行任务功能。并写了个demo学习研究下。

demo地址：http://download.csdn.net/detail/violetjack0808/9474145

参考blog：

Android中定时执行任务的3种实现方法

android service 后台执行定时任务

1. 通过Service和BroadcastReceiver实现

写一个Service执行定时发广播操作

public class AlarmService extends Service {

    @Override  public IBinder onBind(Intent intent) {
        return null;  }

    @Override  public int onStartCommand(Intent intent, int flags, int startId) {
        // TODO: 16/3/28 如果执行费时操作，可以新起线程，但是觉得线程太多不好 // new Thread(new Runnable() { // @Override // public void run() { // } // }).start();  Log.e("test", "这是一条测试信息");  AlarmManager manager = (AlarmManager) getSystemService(ALARM_SERVICE);  int minute = 1000;  long triggerAtTime = SystemClock.elapsedRealtime() + minute;  Intent i = new Intent(this, AlarmReceiver.class);  PendingIntent pi = PendingIntent.getBroadcast(this, 0, i, 0);  manager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, triggerAtTime, pi);  return super.onStartCommand(intent, flags, startId);  }
}

写一个BroadcastReceiver接收广播启动Service

public class AlarmReceiver extends BroadcastReceiver {

    @Override  public void onReceive(Context context, Intent intent) {
        Intent i = new Intent(context, AlarmService.class);  context.startService(i);  }
}

最后在Activity中实现循环。

/**
 * 这个Alarm的循环只能给Service用
 * Activity启动Service，Service发送广播，广播接收器接收广播并启动Service，Service再次发送广播，如此重复
 */
public class AlarmActivity extends AppCompatActivity {

    @Override  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);  setContentView(R.layout.activity_alarm);  Intent i = new Intent(this, AlarmService.class);  startService(i);  }
    
    @Override  protected void onDestroy() {
        super.onDestroy();  Intent i = new Intent(this, AlarmService.class);  stopService(i);  }
}

最后，假如需要对UI进行操作，完全可以将BroadcastReceiver写在Activity中，来实现定时的UI操作。

一直启动Service我不觉得是一个好的解决方案，个人不喜欢用。

2. 通过Handler和Runnable实现循环

/**
 * 通过handler的post方法使用runnable，在runnable中使用handler的post方法post当前runnable,如此循环。
 */
public class HandlerActivity extends AppCompatActivity {

    private TextView tvNumber;  private static int number = 0;   private Handler handler = new Handler();  private Runnable runnable = new Runnable() {
        @Override  public void run() {
            number++;  tvNumber.setText("" + number);  //延时1秒post  handler.postDelayed(this, 1000);  }
    };   @Override  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);  setContentView(R.layout.activity_handler);  tvNumber = (TextView) findViewById(R.id.tvNum01);  findViewById(R.id.btnStart01).setOnClickListener(new View.OnClickListener() {
            @Override  public void onClick(View view) {
                startHandleLoop();  }
        });  findViewById(R.id.btnStop01).setOnClickListener(new View.OnClickListener() {
            @Override  public void onClick(View view) {
                stopHandleLoop();  }
        });   }

    /**  * 开始循环  */  private void startHandleLoop(){
        //延时1秒post  handler.postDelayed(runnable, 1000);  }

    /**  * 停止循环  */  private void stopHandleLoop(){
        handler.removeCallbacks(runnable);  }
}

3. 通过new一个无限循环的线程，设置sleep实现循环

/**
 * 通过新建一个线程，无限循环，并设置sleep时间，实现每隔一秒刷新的功能。
 */
public class SleepActivity extends AppCompatActivity {

    private static int number = 0;  private TextView tvNumber;  private Handler handler3 = new Handler(){
        @Override  public void handleMessage(Message msg) {
            number++;  tvNumber.setText("" + number);  super.handleMessage(msg);  }
    };   @Override  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);  setContentView(R.layout.activity_sleep);  tvNumber = (TextView) findViewById(R.id.tvNum02);  findViewById(R.id.btnStart02).setOnClickListener(new View.OnClickListener() {
            @Override  public void onClick(View view) {
                new Thread(new LoopRnuable()).start();  }
        });  }

    public class LoopRnuable implements Runnable{

        @Override  public void run() {
            while (true) {
                try {
                    Thread.sleep(1000);  Message msg = new Message();  msg.what = 1;  handler3.sendMessage(msg);  } catch (InterruptedException e) {
                    e.printStackTrace();  }
            }
        }
    }
}

4. 通过Timer实现重复循环

/**
 * 通过Timer的schedule方法使用TimerTask，TimerTask的内容是Handler发送消息。
 * 为啥用Handler呢，因为UI变化只能在UI线程~~
 */
public class TimerActivity extends AppCompatActivity {

    private static int number = 0;  private TextView tvNumber;  private Timer timer;  private TimerTask task = new TimerTask() {
        @Override  public void run() {
            //TODO 这里可以执行定时非UI操作  Message message = new Message();  message.what = 1;  handler.sendMessage(message);  }
    };   /**  * 处理UI操作  */  private Handler handler = new Handler() {
        @Override  public void handleMessage(Message msg) {
            super.handleMessage(msg);  number++;  tvNumber.setText("" + number);  }
    };   @Override  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);  setContentView(R.layout.activity_timer);  tvNumber = (TextView) findViewById(R.id.tvNum03);  timer = new Timer();  findViewById(R.id.btnStart03).setOnClickListener(new View.OnClickListener() {
            @Override  public void onClick(View view) {
                startTimmerLoop();  }
        });  findViewById(R.id.btnStop03).setOnClickListener(new View.OnClickListener() {
            @Override  public void onClick(View view) {
                stopTimerLoop();  }
        });  }

    /**  * TODO 当timer被stop之后再次start会报错 timer is canceled  */  private void startTimmerLoop() {
        timer.schedule(task, 1000, 1000);//第二个参数是等待一秒后执行schedule，第三个参数是每隔一秒重复执行一次  }

    private void stopTimerLoop() {
        timer.cancel();  }
}

大多分析都用注释的方式写在代码中了~