Question

我正在开发一个使用actionListener和WindowListener事件的简单应用程序。目的是根据添加到面板的单击按钮使default_close_operation工作。这可以使用内部类轻松完成，但是我想为每个侦听器事件使用不同的类。这是代码：

//test.java
import java.awt.event.WindowEvent;
import javax.swing.*;
public class test extends JFrame 
{
    public static void main(String args[])
    {
        new test();
    }

    private JButton button, exit;
    action a1 = new action();
    close c1 = new close();
    public test()
    {
        this.setSize(200,200);
        this.setTitle("test ");
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        button = new JButton("Button");
        exit = new JButton("Exit");
        exit.addActionListener(c1);
        button.addActionListener(a1);
        JPanel p1 = new JPanel();
        p1.add(button);
        p1.add(exit);
        this.add(p1);
    }

}

// action.java

import javax.swing.*;
import java.awt.event.*;
public class action extends WindowAdapter implements ActionListener
{
    JButton b1;

    public void actionPerformed(ActionEvent e)
    {
        b1 = (JButton)e.getSource();
        if(b1.getText().equalsIgnoreCase("button"))
        {
            b1.setText("Clicked");
        }
        else if(b1.getText().equalsIgnoreCase("exit"))
        {
            System.exit(0);
        }
    }
}

// close.java

import javax.swing.*;
import java.awt.event.*;
public class close extends WindowAdapter
{
    public void windowClosing(WindowEvent e)
    {
        exit.doClick(); //WRONG as no variable exists with exit name.
    }
}

除了close.java类之外，一切都很好。如何将WindowClosing方法指向action类，以便程序以正确的方式终止？

Answer 1

您可以像Action类一样扩展ActionListener并退出Action.java中处理事物的方式

//from your code
else if(b1.getText().equalsIgnoreCase("exit"))
    {
        System.exit(0);
    }

Answer 2

您需要JFrame在您自己的动作侦听器中执行此操作

public class MyListener extends WindowAdapter implements ActionListener
{

    JFrame frame ;
    public MyListener(JFrame component) {
        this.frame = component;
    }


    @Override
    public void actionPerformed(ActionEvent e)
    {
        String actionCommand = e.getActionCommand();
        if(actionCommand.equals("Exit")) {
            //When the last displayable window within the Java virtual 
            // machine (VM) is disposed of, the VM may terminate
            frame.dispose();
        }
    }

    @Override
    public void windowClosing(WindowEvent e) {
             // perfrom operation after window closed
        Component component = e.getComponent();
        String name = component.getName();
        System.out.println("Component " + name + " is closing");

    }


    @Override
    public void windowClosed(WindowEvent e) {
        System.out.println("window is closed");
    }

}

将侦听器添加到框架和按钮

    JFrame frame = new JFrame("Test Frame");   
    buttonExit = new JButton("Exit");
    listener = new MyListener(this);
    frame.addWindowListener(listener);
    buttonExit.addActionListener(listener);

监听器事件的不同类

2 个答案: