Question

我的java程序为何鼠标拖动和键盘事件无法响应

import java.awt.event.*;
import java.awt.*;

public class AppWindow extends Frame {
int mouseX =0,mouseY =0;
String keymsg ="";
String mousemsg ="";
public AppWindow() {
super("test");
addMouseListener(new MyMouseAdapter(this));
addKeyListener(new MyKeyAdapter(this));
}
public void paint(Graphics g) {
g.setColor(Color.blue);
g.drawString(keymsg,10,20);
g.drawString(mousemsg,mouseX,mouseY);
}
public static void main(String[] args) {
AppWindow aw =new AppWindow();
aw.setSize(new Dimension(400,300));
aw.setVisible(true);
}
}
class MyMouseAdapter extends MouseAdapter {
AppWindow aw;
public MyMouseAdapter(AppWindow aw) {
this.aw =aw;
}
public void mousePressed(MouseEvent me) {
int button =me.getButton();
aw.mouseX =me.getX();
aw.mouseY =me.getY();
mousemsg ="down";
aw.repaint();
}
public void mouseReleased(MouseEvent me) {
int button =me.getButton();
aw.mouseX =me.getX();
aw.mouseY =me.getY();
mousemsg ="up";
aw.repaint();
}
//鼠标拖动
public void mouseDragged(MouseEvent me) {
aw.mouseX =me.getX();
aw.mouseY =me.getY();
aw.mousemsg ="*";
aw.repaint();
}
}
class MyKeyAdapter extends KeyAdapter {
AppWindow aw;
public MyKeyAdapter(AppWindow aw) {
this.aw =aw;
}
//键盘事件
public void keyTyped(KeyEvent ke) {
int key =ke.getKeyCode();
switch(key) {
case KeyEvent.VK_UP:
aw.keymsg +="up";
break;
case KeyEvent.VK_DOWN:
aw.keymsg +="down";
break;
}
aw.repaint();
}
}

Answer 1

以下代码，仅供参考，至于具体原因，自己去查：

import java.awt.event.*;
import java.awt.*;

public class AppWindow extends Frame implements MouseMotionListener,
        KeyListener {

    private static final long serialVersionUID = 1L;

    int mouseX = 0, mouseY = 0;
    String keymsg = "";
    String mousemsg = "";

    public AppWindow() {
        super("test");
        addMouseListener(new MyMouseAdapter(this));
        addKeyListener(new MyKeyAdapter(this));
        this.addMouseMotionListener(this); 
        this.addKeyListener(this);
    }

    public void paint(Graphics g) {
        g.setColor(Color.blue);
        g.drawString(keymsg, 10, 20);
        g.drawString(mousemsg, mouseX, mouseY);
    }

    public void repaint_thread() {
        new Thread(new Runnable() {
            @SuppressWarnings("static-access")
            @Override
            public void run() {
                while (true) {
                    try {
                        repaint();
                        Thread.currentThread().sleep(100);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }

    public static void main(String[] args) {
        AppWindow aw = new AppWindow();
        aw.setSize(new Dimension(400, 300));
        aw.setVisible(true);
        aw.repaint_thread();
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        // TODO Auto-generated method stub
        mouseX = e.getX();
        mouseY = e.getY();
        mousemsg = "*";
    }

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

    @Override
    public void keyPressed(KeyEvent arg0) {
        // TODO Auto-generated method stub
         System.out.println(arg0.getKeyCode());  //响应按键按下
    }

    @Override
    public void keyReleased(KeyEvent arg0) {
        // TODO Auto-generated method stub
         System.out.println(arg0.getKeyCode());  //响应按键松开
    }

    @Override
    public void keyTyped(KeyEvent ke) {
         
    }
    
}

@SuppressWarnings("unused")
class MyMouseAdapter extends MouseAdapter {
    AppWindow aw;

    public MyMouseAdapter(AppWindow aw) {
        this.aw = aw;
    }

    public void mousePressed(MouseEvent me) {
        int button = me.getButton();
        aw.mouseX = me.getX();
        aw.mouseY = me.getY();
        aw.mousemsg = "down";
    }

    public void mouseReleased(MouseEvent me) {
        int button = me.getButton();
        aw.mouseX = me.getX();
        aw.mouseY = me.getY();
        aw.mousemsg = "up";
    }
}

class MyKeyAdapter extends KeyAdapter {
    AppWindow aw;

    public MyKeyAdapter(AppWindow aw) {
        this.aw = aw;
    }

    // 键盘事件
    public void keyTyped(KeyEvent ke) {
        int key = ke.getKeyCode();
        switch (key) {
        case KeyEvent.VK_UP:
            aw.keymsg += "up";
            break;
        case KeyEvent.VK_DOWN:
            aw.keymsg += "down";
            break;
        }
        aw.repaint();
    }
}