java - 如何添加 JTextField

Question

我想添加 JTextField。我的 JFrame 包含一个 JButton 和一个 JTextField 。首先，我添加了 JButton，并且它正在工作。但没有看到 JTextField。

import java.awt.*;import java.awt.event.*import java.awt.geom.*;import javax.swing.*;import java.sql.*;import java.util.Random;import java.awt.geom.*;    
public class DrawMap extends JFrame{//private JLabel LabelTitle,MapNo;Private JTextField MapField;private final JButton Load,Back,Logout;private final JPanel DrawPanel;private String UserName,Password,City;public boolean check;private int r,g,b;private int flag =0;private Shape shape;private final int w = 20;
    

    import java.awt.*;
    import java.awt.event.*;
    import java.awt.geom.*;
    import javax.swing.*;
    import java.sql.*;
    import java.util.Random;
    import java.awt.geom.*;

    public class DrawMap extends JFrame{
    //private JLabel LabelTitle,MapNo;
    private JTextField MapField;
    private final JButton Load,Back,Logout;
    private final JPanel DrawPanel;
    private String UserName,Password,City;
    public boolean check;
    private int r,g,b;
    private int flag =0;
    private Shape shape;
    private final int w = 20;
    private final int h = 20;

    private Object lastButtonPressed;

    public DrawMap(String UserName,String Password,String City){

    setTitle("Draw Map");
    setSize(800,600);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    Random p = new Random();
    //r = p.nextInt(255);
    //g = p.nextInt(255);
    //b = p.nextInt(255);

    this.UserName = UserName;
    this.Password = Password;
    this.City   = City;

    final Container contentPane = getContentPane();

    JPanel buttonPanel = new JPanel();
    JPanel buttonPanel1 = new JPanel();
    JPanel TextField = new JPanel();

    /*Draw = new JButton("Draw");
    Shape = new JButton("Shape");*/
    Load = new JButton("Load");
    Back = new JButton("Back");
    Logout = new JButton("Logout");
    
    MapField = new JTextField();
    //MapField.setBounds(130,130,100,30);
    
    TextField.add(MapField);

    //buttonPanel.add(Draw);
    //buttonPanel.add(Shape);
    buttonPanel1.add(Load);
    buttonPanel1.add(Back);
    buttonPanel1.add(Logout);

    contentPane.add(buttonPanel, BorderLayout.NORTH);
    contentPane.add(buttonPanel1, BorderLayout.SOUTH);
    contentPane.add(TextField, BorderLayout.CENTER);

    DrawPanel = new JPanel(){

    };

    contentPane.add(DrawPanel, BorderLayout.CENTER);

    final ActionListener buttonPressed = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent event) {
                lastButtonPressed = event.getSource();
            }
        };

        //Draw.addActionListener(buttonPressed);
        //Shape.addActionListener(buttonPressed);
        Load.addActionListener(buttonPressed);
        Back.addActionListener(buttonPressed);
        Logout.addActionListener(buttonPressed);
        
        contentPane.addMouseListener(new MouseAdapter() {

            public void mouseClicked(MouseEvent e) {

                int x = e.getX();
                int y = e.getY();

                 
                if (lastButtonPressed == Load){
                    //shape = new Rectangle2D.Double(x, y, w, w);
                    //echo("Square",x,y);
                    //color = new Color(0,0,0);
                    
                } 
                else if (lastButtonPressed == Back){
                    UserHome ush = new UserHome(UserName,Password,City);
                    ush.setVisible(true);
                    DrawMap.this.setVisible(false);
                } 
                else if (lastButtonPressed == Logout){
                    Login L = new Login();
                    L.setVisible(true);
                    DrawMap.this.setVisible(false);
                } 

                //DrawPanel.repaint();

                
            }

        });
    
    }
  
    }

Answer 1

基本上，您已将两个组件添加到同一位置...

contentPane.add(TextField, BorderLayout.CENTER);

DrawPanel = new JPanel() {

};

contentPane.add(DrawPanel, BorderLayout.CENTER);

由于 BorderLayout 的工作方式，它只会管理添加到该位置的最后一个组件。

您可能需要考虑使用复合布局，即将按钮和文本字段添加到单独的容器中，然后可以将其与 DrawPanel 一起添加到框架中

您共同的支持之湖Coding Conventions很难推断出你的代码在做什么。这些约定的存在是为了让您更容易理解其他人的代码，也让其他人更容易理解您的代码，我建议花时间尝试学习它们