如何在一個監聽器中識別mouseDragged和mousePressed事件？

Question

在以下代碼中，mouseDragged無法識別。我做錯了什麼？

addMouseListener(new MouseInputAdapter() { 

    @Override 
    public void mouseDragged(MouseEvent e) { ... } 
    @Override 
    public void mousePressed(MouseEvent e) { ... } 

}); 

Answer 1

MouseInputAdapter mia = new MouseInputAdapter() { 
    @Override 
    public void mouseDragged(MouseEvent e) { ... } 
    @Override 
    public void mousePressed(MouseEvent e) { ... } 
}; 
addMouseListener(mia); 
addMouseMotionListener(mia); // <-- You're missing this one. 

Answer 2

，因爲要實現mouseDragged的addMouseListener裏面它是無法識別。

mouseDragged由MouseMotionListener觸發，mousePressed由MouseListener觸發。

因此，您需要實現MouseListener和MouseMotionListener並相應地添加正確的偵聽器。

public class MyClass extends JPanel implements MouseListener, 
               MouseMotionListener { 

    public MyClass() { 
    // whatever code you need, then add the listeners 
    this.addMouseListener(this); 
    this.addMouseMotionListener(this); 
    } 

    public void mousePressed(MouseEvent e) { ... } 
    public void mouseDragged(MouseEvent e) { ... } 

} 

Answer 3

不使用addMouseListener將，但addMouseMotionListener：

addMouseMotionListener(new MouseMotionListener() { 

     @Override 
     public void mouseMoved(MouseEvent e) { 
      // TODO Auto-generated method stub 

     } 

     @Override 
     public void mouseDragged(MouseEvent e) { 
      // TODO Auto-generated method stub 

     } 
    }); 

：d