停止动作侦听器中的摆动计时器

Question

我试图停止ActionListener内部的计时器。以下是我想要做的事情的代码。当我在actionPerformed方法内部满足一定的条件时，我会停止创建的定时器。 timer.stop（）不起作用，编译器不会让我这样做。

任何帮助。建议，建议会非常有帮助。

public class ToggleAnnotationsAction extends IdentifiedMultiAction { 
    //This status indicates if the Toggle action has been completed 

/** 
* Defines the toggling direction of a <code>ToggleAnnotationAction</code> instance. 
*/ 
public static enum Direction {FORWARD, BACKWARD}; 
private Direction myDir; 

/** 
* Create an action with the direction presets given by the provided <code>Enum</code>. 
* 
* @param dir An <code>Enum</code> defined in this class which maps to the correct direction of toggling 
* @see behaviors.multiact.IdentifiedMultiAction#IdentifiedMultiAction(Enum) 
*/ 
public ToggleAnnotationsAction(Direction dir) { 
    super(dir); 
    this.myDir = dir; 
} 

/** 
* Performs the toggling, moving the audio position to the next/previous annotation. 
* 
* Afterward sends an update to all <code>UpdatingActions<code>. 
* 
* Since the waveform display autonomously decides when to paint itself, this action may not result in an instant visual change. 
* 
* <p>Prints warnings if an appropriate Annotation could not be found, despite the action being enabled. 
* 
* @param e The <code>ActionEvent</code> provided by the trigger 
*/ 
public void actionPerformed(ActionEvent e) { 
    //Reset Status to 0 
    status =0; 


    Annotation ann = findAnnotation(myDir, CurAudio.getMaster().framesToMillis(CurAudio.getAudioProgress())); 
    if(ann == null) { 
     System.err.println("It should not have been possible to call " + getClass().getName() + ". Could not find matching annotation"); 
    } 
    else { 
     final long approxFrame = CurAudio.getMaster().millisToFrames(ann.getTime()); 
     final long curFrame = CurAudio.getAudioProgress(); 
     if(approxFrame < 0 || approxFrame > CurAudio.getMaster().durationInFrames() - 1) { 
      GiveMessage.errorMessage("The annotation I am toggling to isn't in range.\nPlease check annotation file for errors."); 
      return; 
     } 

      Timer timer = new Timer(10, new ActionListener() { 
       private long panFrame = curFrame; 
       private long endFrame = approxFrame; 
       public void actionPerformed(ActionEvent evt) { 

        if(myDir == Direction.FORWARD){ 
         if (panFrame >= endFrame) { 

          //How do i Stop my timer here ? 
          return; 
         } 
         CurAudio.setAudioProgressWithoutUpdatingActions(panFrame); 
         panFrame += 4000; 
        } 
       else if(myDir == Direction.BACKWARD){ 
        if (panFrame <= endFrame) { 

         // How do i Stop my timer here ? 
         return; 
        } 
        CurAudio.setAudioProgressWithoutUpdatingActions(panFrame); 
        panFrame -= 4000; 
       } 
      } 

     } 
     ); 

     timer.start(); 

     } 
    MyFrame.getInstance().requestFocusInWindow(); 
} 


/** 
* A forward (backward) <code>ToggleAnnotationsAction</code> should be enabled only when audio is open, not playing, and when there is an annotation following (preceding) the current position. 
*/ 
@Override 
public void update() { 
    if(CurAudio.audioOpen()) { 
     if(CurAudio.getPlayer().getStatus() == PrecisionPlayer.Status.PLAYING) { 
      setEnabled(false); 
     } 
     else { 
      double curTimeMillis = CurAudio.getMaster().framesToMillis(CurAudio.getAudioProgress()); 
      if(findAnnotation(myDir, curTimeMillis) != null) { 
       setEnabled(true); 
      } 
      else { 
       setEnabled(false); 
      } 
     } 
    } 
    else { 
     setEnabled(false); 
    } 
} 

/** 
* Finds the next/previous <code>Annotation</code> relative to a certain audio position in milliseconds. 
* 
* @param dir The direction of movement 
* @param curTimeMillis The present time in milliseconds 
* 
* @return In principle, the <code>Annotation</code> after/before <code>curTimeMillis</code> 
*/ 
private Annotation findAnnotation(Direction dir, double curTimeMillis) { 
    Annotation[] anns = AnnotationDisplay.getAnnotationsInOrder(); 
    if(myDir == Direction.FORWARD) { 
     for(int i = 0; i < anns.length; i++) { 
      if(anns[i].getTime() - curTimeMillis > 1) { 
       return anns[i]; 
      } 
     } 
    } 
    else { 
     for(int i = anns.length - 1; i >= 0; i--) { 
      if(curTimeMillis - anns[i].getTime() > 1) { 
       return anns[i]; 
      } 
     } 
    } 
    return null; 
} 

}

由于提前 克里希南

Answer 1

也是可能的：

final Timer timer = new Timer(10, null); 
timer.addActionListener(new ActionListener() { 
    public void actionPerformed(ActionEvent evt) { 
     (as in the question, except that you can refer to timer here) 
    } 
}); 

或者，使用事件对象获取源代码（然后将其丢，嘘）：

final Timer timer = new Timer(10, new ActionListener() { 
    public void actionPerformed(ActionEvent evt) { 
     ((Timer)evt.getSource()).stop(); 
    } 
}); 

或者，保持计时器在一个实例变量，你可以从你的处理程序中引用它还是有处理程序调用你的类中的方法，该方法可以停止/启动。

Answer 2

趣味的问题。

您必须使Timer最终在您要停止它的匿名ActionListener中访问它。但是匿名ActionListener仍然不会编译，因为Timer尚未初始化。

请注意，计时器可能不是您在此处的最佳选择。但为了使其工作，我会将Timer包装在内部类中。

在你ToggleAnnotationsAction.actionPerformed()方法添加一行：

MyTimer timer = new MyTimer(); 
timer.start(); 

那么可以使用这样的一类，与定时器的ActionListener的代码替换我的简单的ActionListener代码：

private class MyTimer implements ActionListener{ 
    private Timer timer; 

    private MyTimer(){ 
    timer = new Timer(10, this); 
    } 

    public void start(){ 
    timer.start(); 
    } 

    public void stop(){ 
    timer.stop(); 
    } 

    public void actionPerformed(ActionEvent e){ 
    if(isTimeToStop()){ 
     stop(); 
    } 
    } 

    public boolean isTimeToStop(){ 
    return true; 
    } 
}