AWT窗口关闭监听器/事件

Question

我很抱歉,如果这是一个的n00b问题,但我已经花路太长,这一次我创建的窗口侦听器,窗口事件,以及其他一切,我怎么指定调用什么方法？这是我的代码:

private static void mw() {
    Frame frm = new Frame("Hello Java");
    WindowEvent we = new WindowEvent(frm, WindowEvent.WINDOW_CLOSED);
    WindowListener wl = null;
    wl.windowClosed(we);
    frm.addWindowListener(wl);
    TextField tf = new TextField(80);
    frm.add(tf);
    frm.pack();
    frm.setVisible(true);

}

我正在尝试获取一个URL,并下载它,我已经完成了其他所有工作,我只是想让窗口关闭.

Answer 1

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

class FrameByeBye {

    // The method we wish to call on exit.
    public static void showDialog(Component c) {
        JOptionPane.showMessageDialog(c, "Bye Bye!");
    }

    public static void main(String[] args) {
        // creating/udpating Swing GUIs must be done on the EDT.
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {

                final JFrame f = new JFrame("Say Bye Bye!");
                // Swing's default behavior for JFrames is to hide them.
                f.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
                f.addWindowListener( new WindowAdapter() {
                    @Override
                    public void windowClosing(WindowEvent we) {
                        showDialog(f);
                        System.exit(0);
                    }
                } );
                f.setSize(300,200);
                f.setLocationByPlatform(true);
                f.setVisible(true);

            }
        });
    }
}

还要考虑Runtime.addShutdownHook(Thread)在关机前执行任何至关重要的操作.

AWT

这是该代码的AWT版本.

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

class FrameByeBye {

    // The method we wish to call on exit.
    public static void showMessage() {
        System.out.println("Bye Bye!");
    }

    public static void main(String[] args) {
        Frame f = new Frame("Say Bye Bye!");
        f.addWindowListener( new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent we) {
                showMessage();
                System.exit(0);
            }
        } );
        f.setSize(300,200);
        f.setLocationByPlatform(true);
        f.setVisible(true);
    }
}

Answer 2

这个例子展示了如何使用addWindowListener()a WindowAdapter，一个WindowListener接口的具体实现。另请参阅如何编写窗口侦听器。