java - 从监听器中修改 JFrame

Question

<分区>

Answer 1

+1 给@AaronKurtzhals 和@trashgods 对提供以下想法的链接的评论

这是我为帮助您所做的一个简短示例。

解决方案:

1) 在JFrame实例上调用dispose()释放资源

2) 根据需要编辑框架实例，即 setUndecorated(..)

3) 在JFrame 上调用pack() 和setVisible(true)。

当焦点/鼠标悬停时(当 setUndecorated(true) 被调用时我们无法监听焦点事件):

不专心时:

import java.awt.Dimension;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;

public class Test {

    private boolean firstTime2 = true;
    private boolean firstTime = true;
    private JFrame frame;
    private JLabel focusLabel=new JLabel("");

    public Test() {
        initComponents();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();
            }
        });
    }

    private void initComponents() {
        initFrame();
        frame.addMouseMotionListener(new MouseMotionAdapter() {
            @Override
            public void mouseMoved(MouseEvent me) {
                super.mouseMoved(me);
                firstTime2 = false;
                firstTime = false;
                if (frame.isUndecorated()) {
                    focusLabel.setText("Focused");
                    firstTime = true;
                    firstTime2 = true;
                    frame.dispose();
                    frame.setUndecorated(false);
                    showFrame();
                }
            }
        });

        frame.addWindowFocusListener(new WindowAdapter() {
            @Override
            public void windowGainedFocus(WindowEvent e) {
                if (firstTime) {
                    focusLabel.setText("Focused");
                    firstTime = false;
                    frame.dispose();
                    frame.setUndecorated(false);
                    showFrame();
                }
            }

            @Override
            public void windowLostFocus(WindowEvent e) {
                if (!firstTime2) {
                    focusLabel.setText("Not focused");
                    frame.dispose();
                    frame.setUndecorated(true);
                    showFrame();
                }
                firstTime2 = false;
            }
        });

        showFrame();
    }

    private void initFrame() {
        frame = new JFrame() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(300, 300);
            }
        };
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(focusLabel);
    }

    private void showFrame() {
        frame.pack();
        frame.setVisible(true);
    }
}

您可能已经注意到的一些提示:

• 不要不必要地扩展JFrame
• 使用Event Dispatch Thread创建和操作 Swing 组件