关于AddKeyListener事件

Question

import javax.swing.*;
import com.borland.jbcl.layout.XYConstraints;
import com.borland.jbcl.layout.XYLayout;import java.awt.*;
import java.awt.event.*;public class MainFrame extends JFrame{
private Timer timer;
private JButton play=new JButton();
private JButton stop=new JButton();
private JLabel showtext=new JLabel();
private JTextArea textarea=new JTextArea();
private JToolBar status=new JToolBar();
private XYLayout xyLayout = new XYLayout(); //界面布局
private Panel jMainPanel = new Panel();
private CntrPanel cntrpanel=new CntrPanel();

public MainFrame() {
        try {
            setTitle("NewGo");
            setLocation(200, 80);
           // setSize(800, 600);
            jbInit();
            getContentPane().add(jMainPanel, "North");
            getContentPane().addKeyListener(new KeyAdapter() { //主窗口添加键盘监听器
                public void keyPressed(KeyEvent e) {
                    ProcessKeyEvent(e);
                }
            });            addWindowListener(new WindowAdapter() {
                public void windowClosing(WindowEvent e) {
                    dispose();
                }
            });        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
 private void jbInit() throws Exception {
// jMainPanel.setBackground(new Color(72, 112, 112));
     jMainPanel.setForeground(UIManager.getColor(
            "TextArea.selectionBackground"));
    jMainPanel.setLayout(xyLayout);
     
     play.setBackground(Color.pink);
     play.setFont(new java.awt.Font("Dialog", 0, 14));
     play.setForeground(SystemColor.desktop);
     play.setText("Play");
     play.addActionListener(new  PlayButton_actionAdapter(this));
     
     stop.setBackground(Color.pink);
     stop.setFont(new java.awt.Font("Dialog", 0, 14));
     stop.setForeground(SystemColor.desktop);
     stop.setText("Stop");
     stop.addActionListener(new  StopButton_actionAdapter(this));
     
     showtext=new JLabel("Welcome");
     status.add(showtext);
     xyLayout.setWidth(600);
     xyLayout.setHeight(600);
 jMainPanel.add(play,new XYConstraints(50, 10, 150, 30));
 jMainPanel.add(stop,new XYConstraints(350, 10, 150, 30));
 jMainPanel.add(cntrpanel,new XYConstraints(20,50,560,500));
 jMainPanel.add(status,new XYConstraints(0, 570, 600, 30));
    addKeyListener(new KeyAdapter() { //主窗口添加键盘监听器
         public void keyPressed(KeyEvent e) {
             ProcessKeyEvent(e);
         }
     });
 }
 

     }
 public void ProcessKeyEvent(KeyEvent e) {
  showtext.setText("key pressed");
 switch (e.getKeyCode()) {
         case KeyEvent.VK_DOWN: 
          showtext.setText("down");
          break;
         case KeyEvent.VK_UP:
          showtext.setText("up");
          break;
         default:
             break;
 }
 }
 public static void main(String[] args) {
        MainFrame objMainFrame = new MainFrame();
        objMainFrame.pack();
        objMainFrame.setVisible(true);
        objMainFrame.validate();
        objMainFrame.setResizable(false);
    }


}执行后,ProcessKeyEvent()根本就不执行,请高手指点,谢谢!

Answer 1

楼主看看是不是在getContentPane()里面加上了什么Container，
导致你的KEYEVENT永远也不到达getContentPane()?

Answer 2

没有加啊,cntrpanel仅是继承的Panel

Answer 3

你对一个pane进行键盘监听的前提是，这个pane获得着焦点。你把焦点所在的组件名打印一下。或者把焦点强制指定到jMainPanel上面看看。针对你的需求需要类似下面的处理方式
Toolkit toolkit = Toolkit.getDefaultToolkit();
toolkit.addAWTEventListener(new testListener(), AWTEvent.KEY_EVENT_MASK);
监听：
class testListener implements AWTEventListener {
public void eventDispatched(AWTEvent event) {
if(event){Do}
}
}不过这个在整个frame失去焦点后也会失效。