为什么提示框会出现两次？

2006-03-03 11:56:55 149 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

Debian下Rust环境极速安装指南：国内镜像+避坑配置（附清华/中科大源对比）本文详细介绍了在Debian系统上快速安装和配置Rust开发环境的完整指南。针对国内网络环境，重点对比评测了清华大学、中国科学技术大学等主流镜像源，提供了详细的安装配置步骤、Cargo优化技巧以及常见问题排查方案，帮助开发者显著提升依赖下载和编译效率。阅读详情

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

public class ListDemo extends JFrame implements FocusListener {
TextField txtInput1 = new TextField();
TextField txtInput2 = new TextField();
List lst = new List();
JLabel lbl = new JLabel("Sperator");
JButton btn = new JButton("Add");
JPanel plst = new JPanel();

static Boolean show = false;

public ListDemo(){
Container con = getContentPane();
setLayout(new BorderLayout());
con.add("North",plst);
con.add("Center",lst);
con.add("South",btn);
plst.setLayout(new GridLayout(3,1));
plst.add(txtInput1);
plst.add(txtInput2);
plst.add(lbl);
txtInput1.addFocusListener(this);
txtInput2.addFocusListener(this);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}

public static void main(String [] args){
new ListDemo();
}

public void focusLost(FocusEvent fe){
if (((TextField)fe.getSource()).getText().trim().equals("")){
System.out.println(show);
System.out.println(((TextField)fe.getSource()).getName());
show =!show;
if (show){
((TextField)fe.getSource()).requestFocus();
JOptionPane.showMessageDialog(null,"请输入内容","ERROR",JOptionPane.ERROR_MESSAGE);
}
//show =!show;
}
}

public void focusGained(FocusEvent fe){

}

}

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