Question

我有这个按钮，我想为它设置一个计时器，这样用户不必每次都点击它，这样它每20秒自动点击一次这个按钮。我该怎么设置它？

基本上我使用的是tabhost活动，因此总共有3个标签。在第一个选项卡中，有这个按钮，我需要单击按钮，因此我能够从webservice检索信息，这个webservice每次都会更新。当我点击其他选项卡并返回第一个选项卡时，我希望它自动刷新..而不是单击按钮刷新。

            holder.btnClick.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
             }
});

Answer 1

IMO使用ScheduledExecutorService的更有效方式：

private void doTheActualJobWhenButtonClicked() {
  // put whatever you need to do when button clicked here
  ... ...
}

... ...

holder.btnClick.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
    // job triggered by user click button:
    doTheActualJobWhenButtonClicked();
  }
});

... ...

ScheduledExecutorService scheduleTaskExecutor= Executors.newScheduledThreadPool(1);

// This schedule a task to run every 20 seconds:
scheduleTaskExecutor.scheduleAtFixedRate(new Runnable() {
  public void run() {
    // job triggered automatically every 20 seconds:
    doTheActualJobWhenButtonClicked();
  }
}, 0, 20, TimeUnit.SECONDS);

更新：如果您的按钮单击执行某些UI更新，例如TextView中的刷新文本，则只需进行换行 runOnUiThread（）中的方法调用：

private void doTheActualJobWhenButtonClicked() {
  myTextView.setText("refreshed");
}

ScheduledExecutorService scheduleTaskExecutor= Executors.newScheduledThreadPool(1);
// This schedule a task to run every 20 seconds:
scheduleTaskExecutor.scheduleAtFixedRate(new Runnable() {
  public void run() {
    // involved your call in UI thread:
    runOnUiThread(new Runnable() {
      public void run() {
        doTheActualJobWhenButtonClicked();
      }
    });        
  }
}, 0, 20, TimeUnit.SECONDS);

此外，您需要在打开下一个活动或关闭当前活动之前正确关闭ScheduledExecutorService：

// Shut down scheduled task before starting next activity
if (scheduleTaskExecutor != null)
  scheduleTaskExecutor.shutdownNow();
Intent intent = new Intent(getBaseContext(), NextActivity.class);
startActivity(intent);

... ...

public void onDestroy() {
  super.onDestroy();
  // Shut down scheduled task when closing current activity
  if (scheduleTaskExecutor != null)
    scheduleTaskExecutor.shutdownNow();
}

希望得到这个帮助。

Answer 2

由于你有一个按钮，我假设你在某个地方有一个ActionPerformed类型的方法。

鉴于此，您可以这样做：

public class AutoClick extends Thread {
  // Time to wait in milliseconds
  private long wait;

  //Latency excepted
  private long lat;

  AutoClick(long time, long latency) {
    wait = time;
    lat = latency;
  }

  public void run() {
    long start = System.getCurrentTimeMillis();

    long current;
    while(true)
      current = System.getCurrentTimeMillis();
      long step = (current-start) % 20000;
      if(step <= latency || step >= wait-latency)
        //call the action-performed method
  }
}

然后创建一个线程实例并运行它：

public AutoClick clicker = new AutoClick(20000);

clicker.run();

每隔20秒自动点击此按钮的计时器

2 个答案: