JPanel无法正确显示GridBagLayout

Question

import java.awt.*;
import javax.swing.*;

import javax.swing.*;

public class Cashmain extends JFrame{

    private GridBagConstraints gbc;
    Header jpanel1 = new Header();
    Body   jpanel2 = new Body();

    public Cashmain(){
        super("cashcashpinoy");
        Toolkit tk = Toolkit.getDefaultToolkit();
        int xSize = ((int) tk.getScreenSize().getWidth());
        int ySize = ((int) tk.getScreenSize().getHeight());
        setSize(xSize,ySize);
        setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();


        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.anchor = GridBagConstraints.FIRST_LINE_START;
        gbc.fill = GridBagConstraints.BOTH;
        add(jpanel2, gbc);
        gbc.gridx = 0;
        gbc.gridy = 1;
        add(jpanel1, gbc);

面板无法正常显示。框架在中心显示2个小面板。请帮我！

这就是我的程序应该是这样的：

Answer 1

使用BorderLayout会更简单，但除此之外，您的问题是您没有将weighty设置为第二个组件的正值。

这是一个小片段，说明了这两个选项，并允许您切换到另一个。

import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;

public class TestLayouts {

    protected void initUI(final boolean useBorderLayout) {
        final JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JButton header = new JButton("My Header (Click-me to switch layout current layout is "
                + (useBorderLayout ? "BorderLayout" : "GridBagLayout"));
        header.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                TestLayouts.this.initUI(!useBorderLayout);
                frame.dispose();
            }
        });
        JLabel someOtherComponent = new JLabel("Some other component");
        someOtherComponent.setHorizontalAlignment(JLabel.CENTER);
        if (useBorderLayout) {
            frame.getContentPane().setLayout(new BorderLayout());
            frame.getContentPane().add(header, BorderLayout.NORTH);
            frame.getContentPane().add(someOtherComponent, BorderLayout.CENTER);
        } else {
            frame.getContentPane().setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.fill = GridBagConstraints.BOTH;
            frame.getContentPane().add(header, gbc);
            gbc.gridy = 1;
            gbc.weighty = 1.0;
            frame.getContentPane().add(someOtherComponent, gbc);

        }
        frame.setExtendedState(frame.getExtendedState() | JFrame.MAXIMIZED_BOTH);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TestLayouts().initUI(true);
            }
        });
    }

}