GUI 中的 StackOverflow class

Question

谁能解释一下我收到错误消息的原因...

我有两个 classes，一个用于创建 GUI，第二个 class 用于处理事件。源码如下所示...

CLASS 1

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

public class Motion extends JFrame {

MotionEvent controller = new MotionEvent();

//row 0
JPanel row0 = new JPanel();

//row 1
JPanel row1 = new JPanel();
JButton up = new JButton("Up");

//row 2
JPanel row2 = new JPanel();
JButton left = new JButton("Left");
JButton right = new JButton("Right");
JCheckBox compassFormat = new JCheckBox("compassFormat", false);

//row 3
JPanel row3 = new JPanel();
JButton down = new JButton("down");

Motion(){
    super("Motion Detector");
    setSize(500,325);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    GridLayout layoutMaster = new GridLayout(5,1,10,10);
    setLayout(layoutMaster);

    add(row0);

    FlowLayout layout1 = new FlowLayout(FlowLayout.CENTER);
    row1.setLayout(layout1);
    up.addActionListener(controller);
    row1.add(up);
    add(row1);

    GridLayout layout2 = new GridLayout(1, 3, 10, 10);
    row2.setLayout(layout2);
    left.addActionListener(controller);
    //compassFormat.addItemListener(controller);
    right.addActionListener(controller);
    row2.add(left);
    row2.add(compassFormat);
    row2.add(right);
    add(row2);

    FlowLayout layout3 = new FlowLayout(FlowLayout.CENTER);
    row3.setLayout(layout3);
    row3.add(down);
    add(row3);

    setVisible(true);

}

public static void main(String[] args){
    Motion createGui = new Motion();
    }
}

CLASS 2

  import java.awt.event.*;
  import javax.swing.*;
public class MotionEvent implements ActionListener/*, ItemListener */{

Motion motionObj = new Motion();

public void actionPerformed(ActionEvent event){
    Object objSource = event.getSource();
    if(objSource == motionObj.up){
        JOptionPane.showMessageDialog(null, "You have moved up");
    }
    else if(objSource == motionObj.down){
        JOptionPane.showMessageDialog(null, "You have moved down");
    }
    else if(objSource == motionObj.left){
        JOptionPane.showMessageDialog(null, "You have moved left");
    }
    else if(objSource == motionObj.right){
        JOptionPane.showMessageDialog(null, "You have moved right", "Navigator", JOptionPane.INFORMATION_MESSAGE);
    }
}

//public void itemStateChanged(ItemEvent event){


}//

收到的错误信息是：

Exception in thread "main" java.lang.WhosebugError
at sun.awt.Win32GraphicsConfig.getBounds(Native Method)
at sun.awt.Win32GraphicsConfig.getBounds(Unknown Source)
at java.awt.Window.init(Unknown Source)
at java.awt.Window.<init>(Unknown Source)
at java.awt.Frame.<init>(Unknown Source)
at javax.swing.JFrame.<init>(Unknown Source)
at Motion.<init>(Motion.java:26)
at MotionEvent.<init>(MotionEvent.java:5)
at Motion.<init>(Motion.java:6)

Motion.java:6 & MotionEvent.java:5 引用引用变量的实例化，他们有什么问题吗？

Answer 1

存在无限循环running.MeansMotion无限创建

每当创建 Motion 的对象时，也会创建 MotionEvent 的对象

public class Motion extends JFrame {

 MotionEvent controller = new MotionEvent();

每当创建 MotionEvent 的对象时，都会创建 Motion 的对象

  public class MotionEvent implements ActionListener/*, ItemListener */{

  Motion motionObj = new Motion();//which will initiate endless call for this.Remove this

这反过来会导致无休止地创建这两个对象，这显然会导致 Whosebug 错误。移除

Answer 2

这是对 Motion 对象的递归调用，对您的 MotionEvent 使用以下内容 class

import java.awt.event.*;
  import javax.swing.*;
public class MotionEvent implements ActionListener/*, ItemListener */{
 public void actionPerformed(ActionEvent event){
    Object objSource = event.getActionCommand();
    if(objSource.equals("Up")){
        JOptionPane.showMessageDialog(null, "You have moved up");
    }
    else if(objSource .equals("Down")){
        JOptionPane.showMessageDialog(null, "You have moved down");
    }
    else if(objSource.equals("Left")){
        JOptionPane.showMessageDialog(null, "You have moved left");
    }
    else if(objSource.equals("Right")){
        JOptionPane.showMessageDialog(null, "You have moved right", "Navigator", JOptionPane.INFORMATION_MESSAGE);
    }
}

//public void itemStateChanged(ItemEvent event){


}//

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