显示JLabel的问题

Question

您是java的新手，并且一直在尝试为大学项目创建表单。 我处于早期开发阶段，我的文本字段工作，但我的标签不可见。 我的文本区域也很大，拉伸了整个Jframe。 这是我的醋栗代码 当前一个类中的用户登录名为（java.java。）此类被调用（AddProperty.java）

时，此Jframe会自动打开

package Main;

/**
 *
 * @author Graeme
 */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JButton;

public class AddProperty
{

    public void gui()
    {

        JFrame frame = new JFrame("AddPropertyFrame");
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(800,600);
        JPanel panel = new JPanel();
        frame.add(panel);
        panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));

        JLabel HouseNumber = new JLabel();
        panel.add(HouseNumber);
        JTextField HouseNumber1 = new JTextField();
        panel.add(HouseNumber1);

        JLabel HousePrice = new JLabel();
        panel.add(HousePrice);
        JTextField HousePrice1 = new JTextField();
        panel.add(HousePrice1);

        JLabel HouseType = new JLabel();
        panel.add(HouseType);
        JTextField HouseType1 = new JTextField();
        panel.add(HouseType1);

        JButton submit = new JButton("Submit");
        panel.add(submit);
        submit.addActionListener(new Action());
    }

    static class Action implements ActionListener{

        public void actionPerformed (ActionEvent e)
        {

            JFrame frame2 = new JFrame("Submitted");
            frame2.setVisible(true);
            frame2.setSize(200,200);
            JLabel label = new JLabel("You Have Submitted a New Property");
            JPanel panel = new JPanel();
            frame2.add(panel);
            panel.add(label);


        }

    }

}

谢谢，我们非常感谢任何建议。

Answer 1

我认为JLabel不可见，因为它们没有显示在其中的东西......

尝试在调用构造函数时为JLabel赋值...这只是我的猜测...

new JLabel("House Nummber");

Answer 2

请参阅代码中的注释。

更改了AddProperty.java

/**
 *
 * @author Graeme
 */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.border.EmptyBorder;

public class AddProperty
{

    public void gui()
    {

        JFrame frame = new JFrame("AddPropertyFrame");
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // having to set sizes of components is rare, and often a sign    
        // of problems with layouts.
        //frame.setSize(800,600);
        JPanel panel = new JPanel(new FlowLayout(FlowLayout.CENTER, 20,20));
        // make it big like the original
        panel.setBorder(new EmptyBorder(100,20,100,20));
        frame.add(panel);
        //panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));

        JLabel HouseNumber = new JLabel("A");
        panel.add(HouseNumber);
        JTextField HouseNumber1 = new JTextField(10);
        panel.add(HouseNumber1);

        JLabel HousePrice = new JLabel("B");
        panel.add(HousePrice);
        JTextField HousePrice1 = new JTextField(10);
        panel.add(HousePrice1);

        JLabel HouseType = new JLabel("C");
        panel.add(HouseType);
        JTextField HouseType1 = new JTextField(5);
        panel.add(HouseType1);

        JButton submit = new JButton("Submit");
        panel.add(submit);
        submit.addActionListener(new Action());

        // tell the GUI to assume its natural (minimum) size.
        frame.pack();
    }

    static class Action implements ActionListener{

        public void actionPerformed (ActionEvent e)
        {
            // this should probably be a modal JDialog or JOptionPane.
            JFrame frame2 = new JFrame("Submitted");
            frame2.setVisible(true);
            frame2.setSize(200,200);
            JLabel label = new JLabel("You Have Submitted a New Property");
            JPanel panel = new JPanel();
            frame2.add(panel);
            panel.add(label);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                AddProperty addProperty = new AddProperty();
                addProperty.gui();
            }
        });
    }
}

屏幕截图

Answer 3

未显示JLabel的原因是因为没有显示任何值。

尝试在调用其构造函数时添加一个值，例如;

new JLabel("House Nummber");