怎麼去上的MouseEvent一個JFrame

Question

我寫了這個實施mouseinputlistener方法

public void mouseDragged(MouseEvent e){ 
    Pion c = (Pion)e.getSource(); 
    c.setBounds(e.getX() + c.getX(), e.getY() + c.getY(), 30, 30); 

} 

，我在課堂上這是JFrame的擴展實現內部發生的元素的引用，它包含一個網格佈局不同的組件：JPanel和一些面板包含Jbutton將

我需要的是，讓我對發生事件是否是一個JPanel或JButton組件的引用的方法。

我嘗試用e.getSource，但顯然這是行不通的，代碼編譯，但我得到一個異常說「高原（即當前延伸JFrame類）不能被澆鑄成介子（即一個類擴展爲JButton）「每當我在組件上拖動鼠標

我試圖實現MouseInputListener擴展組件（Pion和其他）的每個類，但我需要在JFrame比例上執行操作，不允許這樣做。

這裏的例外，我得到：

java.lang.ClassCastException: PlateauColorLine cannot be cast to javax.swing.JPanel 
at PlateauColorLine.mouseDragged(PlateauColorLine.java:299) 
at java.awt.Component.processMouseMotionEvent(Component.java:6564) 
at java.awt.Component.processEvent(Component.java:6285) 
at java.awt.Container.processEvent(Container.java:2229) 
at java.awt.Window.processEvent(Window.java:2022) 
at java.awt.Component.dispatchEventImpl(Component.java:4872) 
at java.awt.Container.dispatchEventImpl(Container.java:2287) 
at java.awt.Window.dispatchEventImpl(Window.java:2719) 
at java.awt.Component.dispatchEvent(Component.java:4698) 
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:747) 
at java.awt.EventQueue.access$300(EventQueue.java:103) 
at java.awt.EventQueue$3.run(EventQueue.java:706) 
at java.awt.EventQueue$3.run(EventQueue.java:704) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77) 
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87) 
at java.awt.EventQueue$4.run(EventQueue.java:720) 
at java.awt.EventQueue$4.run(EventQueue.java:718) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77) 
at java.awt.EventQueue.dispatchEvent(EventQueue.java:717) 
at org.GNOME.Accessibility.AtkWrapper$5.dispatchEvent(AtkWrapper.java:697) 
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242) 
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161) 
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150) 
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146) 
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) 
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91) 

`

Answer 1

希望，這將有助於

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 

class Pion extends JButton 
{ 
    public Pion (String title) 
    { 
     super(title); 
     addMouseListener(new MouseListnerAdapter()); 
    } 
} 

class MouseListnerAdapter extends MouseAdapter 
{ 
    @Override 
    public void mousePressed(MouseEvent e) { 
     Object o = e.getSource(); 

     if(o instanceof JButton) 
     { 
      JButton b = (JButton) o; 
      b.setBounds(e.getX() + b.getX(), e.getY() + b.getY(), 30, 30); 
     } 
    } 
}; 


public class Test extends JFrame { 
    public Test() 
    { 
     super("Test");   
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     setLayout(new GridLayout(2,1)); 


     JPanel p1 = new JPanel(); 
     Pion pb1 = new Pion("button1"); 
     p1.add(pb1); 
     add(p1); 

     JPanel p2 = new JPanel(); 
     Pion pb2 = new Pion("button2"); 
     p2.add(pb2); 
     add(p2);   

     pack(); 
     setSize(240, 240); 
     setLocationByPlatform(true); 
     setVisible(true); 
     addMouseListener(new MouseListnerAdapter()); 

    } 

    public static void main(String[] args)throws Exception 
    { 
     new Test(); 
    } 
} 

Answer 2

java.lang.ClassCastException: PlateauColorLine cannot be cast to javax.swing.JPanel 

事件的來源是JPanel的，因爲你添加的MouseListener到面板。

如果你想在面板的該位置的按鈕，然後你需要搜索面板在面板上的位置找到該組件。

喜歡的東西：

JPanel panel = (JPanel)e.getSource(); 
Component c = panel.getComponentAt(e.getPoint()); 

if (c != null) 
    Pion p = (Pion)c;