布局使 JFrame 最小且没有内容

Question

我想制作一个包含两个 JPanel 的 JFrame，感谢 Layout。左边是结果（尽管 setExtendedState(JFrame.MAXIMIZED_BOTH);），右边是我调整框架大小时的结果：

这是最小化的代码：

import java.awt.Color;
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.JPanel;

/**
 * The Frame which will contain one or two Panels.
 *
 */
class Frame extends JFrame {

    private static final long serialVersionUID = 1L;
    private JPanel panAction;

    public void JFrame() {
        setLayout(new GridBagLayout());

        GridBagConstraints info = new GridBagConstraints();
        info.gridx = info.gridy = 0;
        //info.gridwidth = 1;
        //info.gridheight = 2;
        info.fill = GridBagConstraints.BOTH;
        //info.weightx = 1;
        //info.weighty = 1;
        JPanel buttonPanel = new ButtonPanel(this);
        add(buttonPanel, info);

        setExtendedState(JFrame.MAXIMIZED_BOTH);
        pack();
    }

    public void changeSecondPanel(JPanel panel) {
        if(this.panAction != null) {
            remove(this.panAction);
        }

        GridBagConstraints info = new GridBagConstraints();
        info.gridx = 0;
        info.gridy = 1;
        //info.gridwidth = 1;
        //info.gridheight = 2;
        //info.weightx = 1;
        //info.weighty = 1;
        info.fill = GridBagConstraints.BOTH;

        add(panAction, info);
        this.panAction = panel;
    }
}

/**
 * The upper Panel.
 *
 */
class ButtonPanel extends JPanel {

    private static final long serialVersionUID = 1L;

    public ButtonPanel(final Frame frame) {
        setBackground(Color.BLUE);
        JButton button = new JButton("CREATE");
        button.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent arg0) {
                frame.changeSecondPanel(
                        /**
                         * The bottom Panel.
                         */
                        new JPanel() {

                    private static final long serialVersionUID = 1L;

                    {
                        setBackground(Color.GREEN);
                    }
                });
            }
        });
    }
}


public class PanelProblem {

    public static void main(String[] args) {
        new Frame().setVisible(true);
    }

}

我尝试了GridLayout和BorderLayout，但没有解决我的问题。我已经检查了 Can components of a gridbaglayout fill parent frame upon resize?, GridBagLayout doesn't fill all the space 和许多其他来源。

Answer 1

名为 JFrame 的 void 方法看起来很可疑。

public void JFrame() { ... }

我想你打算写一个像

这样的构造函数

public Frame() { ... }

您编写的布局代码未被调用。此修复将解决该问题。

希望对您有所帮助。

布局使 JFrame 最小且没有内容

The layout makes the JFrame minimal and there is no content

java

swing

jpanel

jframe

layout-manager