Update

src/高级事件处理/Focus.java

+package 高级事件处理;
+
+// !/usr/bin/env jdk1.8
+// encoding:utf-8
+//@software:IntelliJ IDEA
+//@pack:高级事件处理
+//@user:彭友聪
+//@date:2019/6/25
+//@time:9:54
+//@project:IDEA_JAVA
+//@file:Focus.java
+//Author:御承扬
+//email:2923616405@qq.com
+
+
+import javax.swing.*;
+import javax.swing.border.EmptyBorder;
+import java.awt.*;
+import java.awt.event.WindowEvent;
+import java.awt.event.WindowFocusListener;
+
+public class Focus extends JFrame {
+    private JLabel lbLight;
+    private JLabel lbTip;
+
+
+    public static void main(String[] args) {
+        Focus frame = new Focus();
+        frame.setVisible(true);
+    }
+
+    private class myWindowFocusListener implements WindowFocusListener {
+        @Override
+        public void windowGainedFocus(WindowEvent e) {
+            // 设置标签中的图标，显示灯亮
+            lbLight.setIcon(new ImageIcon(Focus.class.getResource("light.png")));
+            lbTip.setText("JFrame 窗体获得焦点后，灯亮了。。。");
+        }
+
+        @Override
+        public void windowLostFocus(WindowEvent e) {
+            // 设置标签中的图标，显示灯灭
+            lbLight.setIcon(new ImageIcon(Focus.class.getResource("dark.png")));
+            lbTip.setText("JFrame 窗体失去焦点后，灯灭了...");
+        }
+    }
+
+    private Focus() {
+        addWindowFocusListener(new myWindowFocusListener());  // 为窗体添加焦点事件监听器
+        setAutoRequestFocus(false);  // JFrame 窗体失去焦点
+        setResizable(false);  // 卟可改变窗体大小
+        setTitle("焦点事件的监听");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setBounds(100, 100, 500, 400);
+        // 创建JPanel面板contentPane置于JFrame窗体中，并设置面板的背景色、边距和布局
+
+        JPanel contentPane = new JPanel();
+        contentPane.setBackground(Color.BLACK);
+        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
+        contentPane.setLayout(new BorderLayout(0, 0));
+        setContentPane(contentPane);
+        // 创建标签lblTip置于JFrame窗体中的南侧，设置标签label_1中字体的颜色、样式以及水平居中
+
+        lbTip = new JLabel("JFrame 窗体失去焦点时，灯没亮！");
+        lbTip.setForeground(Color.CYAN);
+        lbTip.setFont(new Font("楷体", Font.PLAIN, 24));
+        lbTip.setHorizontalAlignment(SwingConstants.CENTER);
+        contentPane.add(lbTip,BorderLayout.SOUTH);
+        //  创建标签lblLight置于JFrame窗体中的中间，设置标签label_2中的图标位置和样式
+
+        lbLight = new JLabel("");
+        lbLight.setHorizontalAlignment(SwingConstants.CENTER);
+        lbLight.setIcon(new ImageIcon(Focus.class.getResource("dark.png")));
+        contentPane.add(lbLight,BorderLayout.NORTH);
+    }
+}