Android定时器实现定时执行、重复执行、定时重复执行、定次数执行的多种方式

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package com.example.leixiansheng.mytimers;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.util.Timer;
import java.util.TimerTask;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
  private Button timer_1, timer_2, timer_3, timer_4,clear, showTime;
  private Timer timer;
  private TimerTask timerTask;
  private int num = 0;    //计数值
  private boolean flog = true;    //是否停止计时
  private Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      super.handleMessage(msg);
      showTime.setText("点击我停止计时： " + msg.what);
    }
  };
  //handler 方式定时循环
  private Handler handlerTimer = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      super.handleMessage(msg);
      if (flog) {
        handlerTimer.sendEmptyMessageDelayed(num++, 1000);
      }
      showTime.setText("点击我停止计时： " + msg.what);
      if(flog == false) {
       flog = true;
      }
    }
  };
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    timer_1 = (Button) findViewById(R.id.timer_1);
    timer_2 = (Button) findViewById(R.id.timer_2);
    timer_3 = (Button) findViewById(R.id.timer_3);
    timer_4 = (Button) findViewById(R.id.timer_4);
    clear = (Button) findViewById(R.id.clear);
    showTime = (Button) findViewById(R.id.show_time);
    timer_1.setOnClickListener(this);
    timer_2.setOnClickListener(this);
    timer_3.setOnClickListener(this);
    timer_4.setOnClickListener(this);
    clear.setOnClickListener(this);
    showTime.setOnClickListener(this);
  }
  @Override
  public void onClick(View view) {
    switch (view.getId()) {
      case R.id.timer_1:
        method_1();
        break;
      case R.id.timer_2:
        method_2();
        break;
      case R.id.timer_3:
        method_3();
        break;
      case R.id.timer_4:
        method_4();
        break;
      case R.id.clear:
        num = 0;
        showTime.setText("请选择一种启动方式");
        break;
      case R.id.show_time:
        flog = false;
        break;
    }
  }
  private void method_4() {
      new Thread() {
        @Override
        public void run() {
          super.run();
          handlerTimer.sendEmptyMessage(num++);
        }
      }.start();
  }
  private void method_3() {
    //Timer一旦被cancel之后就废了，只有重新构造一个。
    if (flog == true) {
      timer = new Timer();
      timerTask = new TimerTask() {
        @Override
        public void run() {
          handler.sendEmptyMessage(num++);
        }
      };
      /**
       * 第一个参数：任务
       * 第二个参数：初始启动等待时间
       * 第三个参数：时间间隔
       */
      timer.schedule(timerTask, 0, 1000);
    } else {
      timer.cancel();
      // 一定设置为null，否则定时器不会被回收
      timer = null;
      flog = true;
    }
    //Timer 暂停重启有问题（待改进）
    //Timer一旦被cancel之后就废了，只有重新构造一个。
//    if (flog == true) {
//      timerTask = new TimerTask() {
//        @Override
//        public void run() {
//          handler.sendEmptyMessage(num++);
//        }
//      };
//      /**
//       * 第一个参数：任务
//       * 第二个参数：初始启动等待时间
//       * 第三个参数：时间间隔
//       */
//      timer.schedule(timerTask, 0, 1000);
//    } else {
//      timer.cancel();
//      flog = true;
//    }
  }
  private void method_2() {
    //new Thread().start();
    new Thread() {
      @Override
      public void run() {
        super.run();
        while (flog) {
          handler.sendEmptyMessage(num++);
          try {
            Thread.sleep(1000);
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
      }
    }.start();
    flog = true;
  }
  private void method_1() {
//    new Thread(new Runnable).start();
    new Thread(new Runnable() {
      @Override
      public void run() {
        while (flog) {
          handler.sendEmptyMessage(num++);
          try {
            Thread.sleep(1000);
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
      }
    }).start();
    flog = true;
  }
}