Android定时器Timer的停止和重启实现代码

本文介绍了android定时器timer的停止和重启实现代码，分享给大家，具体如下：

7月份做了一个项目，利用自定义控件呈现一幅动画，当时使用定时器来控制时间，但是当停止开启时总是出现问题。一直在寻找合理的方法解决这个问题，一直没有找到，最近终于找到了合理的方法来解决这个问题。

大家如何查询有关资料，一定知道timer,timertask取消的方式是采用timer.cancel()和mtimertask.cancel()，可是大家发现这种发式取消后，再次开始timer时，会报错

 fatal exception: main
         process: com.example.zhongzhi.gate_control_scheme, pid: 2472
         java.lang.illegalstateexception: timer already cancelled.
           at java.util.timer.sched(timer.java:397)
           at java.util.timer.schedule(timer.java:248)
           at com.example.zhongzhi.gate_control_scheme.mainactivity.onclick(mainactivity.java:401)
           at android.view.view.performclick(view.java:5637)
           at android.view.view$performclick.run(view.java:22429)
           at android.os.handler.handlecallback(handler.java:751)
           at android.os.handler.dispatchmessage(handler.java:95)
           at android.os.looper.loop(looper.java:154)
           at android.app.activitythread.main(activitythread.java:6119)
           at java.lang.reflect.method.invoke(native method)
           at com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:886)
           at com.android.internal.os.zygoteinit.main(zygoteinit.java:776)

 这个问题的解决采用cancle(),取消timer后，还需要清空timer。合理的代码应该是这样的：

mtimer.cancel();
mtimer = null;
mtimertask.cancel();
mtimertask = null;

关键的问题解决完了，下面给出我的案例代码mainactivity.java：

public class mainactivity extends appcompatactivity {

  private static string tag = "timerdemo";
  private textview mtextview = null;
  private button mbutton_start = null;
  private button mbutton_pause = null;
  private timer mtimer = null;
  private timertask mtimertask = null;
  private handler mhandler = null;
  private static int count = 0;
  private boolean ispause = false;
  private boolean isstop = true;
  private static int delay = 1000; //1s
  private static int period = 1000; //1s
  private static final int update_textview = 0;

  @override
  public void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
    mtextview = (textview)findviewbyid(r.id.mytextview);
    mbutton_start = (button)findviewbyid(r.id.mybutton_start);
    mbutton_pause = (button)findviewbyid(r.id.mybutton_pause);


    mbutton_start.setonclicklistener(new button.onclicklistener() {
      public void onclick(view v) {
        if (isstop) {
          log.i(tag, "start");
        } else {
          log.i(tag, "stop");
        }

        isstop = !isstop;

        if (!isstop) {
          starttimer();
        }else {
          stoptimer();
        }

        if (isstop) {
          mbutton_start.settext(r.string.start);
        } else {
          mbutton_start.settext(r.string.stop);
        }
      }
    });

    mbutton_pause.setonclicklistener(new button.onclicklistener() {
      public void onclick(view v) {
        if (ispause) {
          log.i(tag, "resume");
        } else {
          log.i(tag, "pause");
        }

        ispause = !ispause;

        if (ispause) {
          mbutton_pause.settext(r.string.resume);
        } else {
          mbutton_pause.settext(r.string.pause);
        }
      }
    });

    mhandler = new handler(){
      @override
      public void handlemessage(message msg) {
        switch (msg.what) {
          case update_textview:
            updatetextview();
            break;
          default:
            break;
        }
      }
    };
  }

  private void updatetextview(){
    mtextview.settext(string.valueof(count));
  }

  private void starttimer(){
    if (mtimer == null) {
      mtimer = new timer();
    }

    if (mtimertask == null) {
      mtimertask = new timertask() {
        @override
        public void run() {
          log.i(tag, "count: "+string.valueof(count));
          sendmessage(update_textview);

          do {
            try {
              log.i(tag, "sleep(1000)...");
              thread.sleep(1000);
            } catch (interruptedexception e) {
            }
          } while (ispause);

          count ++;
        }
      };
    }

    if(mtimer != null && mtimertask != null )
      mtimer.schedule(mtimertask, delay, period);

  }

  private void stoptimer(){
    if (mtimer != null) {
      mtimer.cancel();
      mtimer = null;
    }
    if (mtimertask != null) {
      mtimertask.cancel();
      mtimertask = null;
    }
    count = 0;
  }

  public void sendmessage(int id){
    if (mhandler != null) {
      message message = message.obtain(mhandler, id);
      mhandler.sendmessage(message);
    }
  }
}

xml部分代码：

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:orientation="vertical" >
  <textview
    android:id="@+id/mytextview"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:text="@string/number" />

  <linearlayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:orientation="horizontal" >

    <button
      android:id="@+id/mybutton_start"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/start" />

    <button
      android:id="@+id/mybutton_pause"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/pause" />
  </linearlayout>
</linearlayout>

string部分代码：

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string name="app_name">timerdemo</string>
  <string name="number">0</string>
  <string name="start">start</string>
  <string name="stop">stop</string>
  <string name="pause">pause</string>
  <string name="resume">resume</string>
</resources>

上面就是我的源代码，如果大家有什么问题可以留言进行探讨。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。