java中如何检测特定窗口何时关闭

Question

我对Java还很陌生，我试着查了一下，但没有找到任何有用的东西。我想知道我怎么能检测到一个特定的窗口关闭了？我一直在使用windowClosing（），但这适用于关闭的任何窗口，因此如果窗口B关闭，我希望由于窗口a关闭而发生的事件也会发生。我如何只在窗口A关闭的情况下进行检测？抱歉，如果这是一个糟糕的措辞，我不知道那么多Java术语。提前致谢：）

package gui_login;

//awt classes
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

//swing classes
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JPasswordField;
import javax.swing.JOptionPane;
import javax.swing.JButton;

public class windowtest implements ActionListener, WindowListener
{
//get JFrame
    JFrame JFrame = new JFrame();

    public static JFrame frameA = new JFrame("FrameA");
    public static JFrame frameB = new JFrame("FrameB");
    static windowtest windowtest = new windowtest();

public static void main(String[] args) 
{
    windowtest.frames();
}

public void frames()
{
    frameA.setLayout(new FlowLayout());
    frameA.setSize(220, 130);
    frameA.setVisible(true);
    frameA.addWindowListener(this);

    frameB.setLayout(new FlowLayout());
    frameB.setSize(220, 130);
    frameB.setVisible(true);
    frameB.addWindowListener(this);
}

public void windowClosing(WindowEvent e) {
    System.out.println("Yo");
}
public void windowActivated(WindowEvent e) {
}
public void windowClosed(WindowEvent e) {
}
public void windowDeactivated(WindowEvent e) {
}
public void windowDeiconified(WindowEvent e) {
}
public void windowIconified(WindowEvent e) {
}
public void windowOpened(WindowEvent e) {
}
public void actionPerformed(ActionEvent e) {
}
}

Answer 1

因为FrameA和FrameB使用的都是WindowListener(this)的同一实例，所以当任何一个帧关闭时，您的WindowListener都会被通知（两者/两者）。

您可以使用WinDoWeVent#GetSource获取事件的源，但更简单的解决方案可能是为每个帧提供自己的WindowListener实例，这样，您就不需要对正在发生的事情做出假设

import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class WindowTest {
//get JFrame

    JFrame JFrame = new JFrame();

    public static JFrame frameA = new JFrame("FrameA");
    public static JFrame frameB = new JFrame("FrameB");
    static WindowTest windowtest = new WindowTest();

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                windowtest.frames();
            }
        });
    }

    public void frames() {
        frameA.setLayout(new FlowLayout());
        frameA.setSize(220, 130);
        frameA.setVisible(true);
        frameA.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                System.out.println("A is closing");
            }

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

        });

        frameB.setLayout(new FlowLayout());
        frameB.setSize(220, 130);
        frameB.setVisible(true);
        frameB.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                System.out.println("B is closing");
            }

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

        });
    }
}

您可能以前没有见过匿名类，请看一下匿名类

一般而言，不再需要实现不向类提供直接功能的接口（就像ActionListener和WindowListener)。原因是，这些接口要求您实现的方法是Public，但没有人真的应该直接调用它们。

这允许您在类内部“隐藏”实现细节，并防止未知调用方可能的误用

您可能还想看看嵌套类