java - 为什么 Jpanels 不工作？

Question

我正在尝试使用 JPanel 编写一个程序，但在我的一生中，我似乎无法让 JPanel 进入正确的位置。我不知道我做错了什么。

这是我迄今为止的一些代码:

package mainGUIWindowFrames;

import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class CustomerWindow extends JFrame
{
//Attribute
private JTextField      textTF;
private JButton         copyButton;
private JLabel          copyLabel;
private Border          panelEdge;

//Constructor
public CustomerWindow()
{
    this.setBounds(100,100,800,600);
    panelEdge = BorderFactory.createEtchedBorder();

    JPanel mainPanel = new JPanel(new BorderLayout(5, 5));
    mainPanel.add(createCustomerPanel(), BorderLayout.NORTH);
    mainPanel.add(createCustomerInfoPanel(), BorderLayout.EAST);
    mainPanel.add(createSearchPanel(), BorderLayout.WEST);
}

//Operational Methods
public JPanel createCustomerPanel()
{
    JPanel customerPanel = new JPanel();

    JLabel customerL = new JLabel("Clients",SwingConstants.CENTER);
    customerL.setForeground(Color.blue);
    customerL.setFont(new Font("Copperplate Gothic Bold",Font.BOLD,48));
    customerPanel.add(customerL);


    customerPanel.setBorder(panelEdge);

    return customerPanel;
}

public JPanel createCustomerInfoPanel()
{
    JPanel infoPanel = new JPanel();
    infoPanel.setBorder(panelEdge);

    JLabel infoL = new JLabel("Clients",SwingConstants.CENTER);
    infoL.setForeground(Color.blue);
    infoL.setFont(new Font("Copperplate Gothic Bold",Font.BOLD,48));
    infoPanel.add(infoL);


    //add a text field
    textTF = new JTextField(50);
    infoPanel.add(textTF);

    //add a button
    copyButton = new JButton("Copy Text");
    copyButton.addActionListener(new ButtonListener());
    infoPanel.add(copyButton);

    copyLabel = new JLabel("-----------------");

    infoPanel.add(copyLabel);


    return infoPanel;
}

public JPanel createSearchPanel()
{
    JPanel lowerPanel = new JPanel();
    JLabel label = new JLabel("Text Transferred from JList:");

    //the spot where the data shows up

    lowerPanel.add(label);
    return lowerPanel;
}

唯一显示的面板是 CreateCustomerPanel()。我不知道需要做什么才能让其他两个面板正常工作。

如果你能帮助我那就太好了!!

<小时/>

好吧，我最终通过创建另一个面板并将面板移出主构造函数来解决这个问题。

public CustomerWindow() {

    panelEdge = BorderFactory.createEtchedBorder();




}
public  JPanel createNorthPanel()
{
    JPanel customerPanel = new JPanel();
    JLabel customerL = new JLabel("Clients",SwingConstants.CENTER);
    customerL.setForeground(Color.blue);
    customerL.setFont(new Font("Copperplate Gothic Bold",Font.BOLD,48));
    customerPanel.add(customerL);


    customerPanel.setBorder(panelEdge);

    return customerPanel;

}   
//Operational Methods
public JPanel createCustomerPanel()
{
    JPanel mainPanel = new JPanel(new BorderLayout(5, 5));
    mainPanel.add(createNorthPanel(), BorderLayout.NORTH);
    mainPanel.add(createCustomerInfoPanel(), BorderLayout.EAST);
    mainPanel.add(createSearchPanel(), BorderLayout.WEST);

    return mainPanel;


}


public JPanel createCustomerInfoPanel()
{
    JPanel infoPanel = new JPanel();
    Box vBox = Box.createVerticalBox();
    infoPanel.setBorder(panelEdge);


    JLabel infoL = new JLabel("Clients",SwingConstants.CENTER);
    infoL.setForeground(Color.blue);
    infoL.setFont(new Font("Copperplate Gothic Bold",Font.BOLD,48));
    infoPanel.add(infoL);


    //add a text field
    clientId = new JTextField(10);
    vBox.add(clientId);
    vBox.add(Box.createVerticalStrut(25));
    fName = new JTextField(10);
    vBox.add(fName);
    vBox.add(Box.createVerticalStrut(25));
    lName = new JTextField(10);
    vBox.add(lName);
    vBox.add(Box.createVerticalStrut(25));
    address = new JTextField(10);
    vBox.add(address);
    vBox.add(Box.createVerticalStrut(25));
    postalCode = new JTextField(10);
    vBox.add(postalCode);
    vBox.add(Box.createVerticalStrut(25));
    number = new JTextField(10);
    vBox.add(number);
    vBox.add(Box.createVerticalStrut(25));
    type = new JTextField(10);
    vBox.add(type);


    infoPanel.add(vBox);


    return infoPanel;

我还有很多工作要做，但感谢所有帮助我的人!!

Answer 1

根据您的示例，不应显示任何内容，因为您尚未将 mainPanel 添加到任何内容。

一旦我这样做了，我就能够得到

出现...

修改后的代码示例

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.Border;

public class CustomerWindow extends JFrame {
//Attribute

    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) {
                }

                CustomerWindow frame = new CustomerWindow();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    private JTextField textTF;
    private JButton copyButton;
    private JLabel copyLabel;
    private Border panelEdge;

//Constructor
    public CustomerWindow() {
        this.setBounds(100, 100, 800, 600);
        panelEdge = BorderFactory.createEtchedBorder();

        JPanel mainPanel = new JPanel(new BorderLayout(5, 5));
        mainPanel.add(createCustomerPanel(), BorderLayout.NORTH);
        mainPanel.add(createCustomerInfoPanel(), BorderLayout.EAST);
        mainPanel.add(createSearchPanel(), BorderLayout.WEST);

        add(mainPanel);
    }

//Operational Methods
    public JPanel createCustomerPanel() {
        JPanel customerPanel = new JPanel();

        JLabel customerL = new JLabel("Clients", SwingConstants.CENTER);
        customerL.setForeground(Color.blue);
        customerL.setFont(new Font("Copperplate Gothic Bold", Font.BOLD, 48));
        customerPanel.add(customerL);

        customerPanel.setBorder(panelEdge);

        return customerPanel;
    }

    public JPanel createCustomerInfoPanel() {
        JPanel infoPanel = new JPanel();
        infoPanel.setBorder(panelEdge);

        JLabel infoL = new JLabel("Clients", SwingConstants.CENTER);
        infoL.setForeground(Color.blue);
        infoL.setFont(new Font("Copperplate Gothic Bold", Font.BOLD, 48));
        infoPanel.add(infoL);

        //add a text field
        textTF = new JTextField(50);
        infoPanel.add(textTF);

        //add a button
        copyButton = new JButton("Copy Text");
//        copyButton.addActionListener(new ButtonListener());
        infoPanel.add(copyButton);

        copyLabel = new JLabel("-----------------");

        infoPanel.add(copyLabel);

        return infoPanel;
    }

    public JPanel createSearchPanel() {
        JPanel lowerPanel = new JPanel();
        JLabel label = new JLabel("Text Transferred from JList:");

        //the spot where the data shows up
        lowerPanel.add(label);
        return lowerPanel;

    }

}