BoxLayout仅显示最后添加的组件

Question

看了一些以前关于我主题的帖子，但也没有用。

试图使用BoxLayout对齐组件，但我无法使其工作。我对它进行了一段时间的修改，得到了不同的结果，但我无法弄清楚。我已经使用了默认的FlowLayout，没有任何问题，我正在努力学习和扩展我的知识，BoxLayout将对我的程序更好。如果用户调整其应用程序窗口的大小，我希望所有内容保持一致。在试着让它发挥作用但失败后，我用这种方式调整了所有的尺寸。

package GUI;
import javax.swing.*;
import java.awt.*;
 /**
 * Created by Thunderfoot on 7/31/2016. Keep Growing!
 * Graphical User Interface
 * Needs 3 JPanels(Text area + scroll pane)(2 Buttons) (1 Button), a    JTextArea, JScrollPane, and 3 JButtons
 */
public class PrimaryFrame extends JFrame {
    //Class variables
    private static JPanel panel1, panel2, panel3;
    public static JTextArea output;
    //Constructor
    public PrimaryFrame() {
        //Frame component attributes
        final Dimension FRAME_SIZE = new Dimension(400, 400);
        final Dimension PANEL1_SIZE = new Dimension(400, 250);
        final Dimension PANEL2_SIZE = new Dimension(400, 40);
        final Dimension PANEL3_SIZE = new Dimension(400, 40);
        //JFrame is PrimaryFrame
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setPreferredSize(FRAME_SIZE);
        setMaximumSize(FRAME_SIZE);
        setTitle("Fighting Game");
        //JPanel for Text
        panel1 = new JPanel();
        panel1.setLayout(new BoxLayout(panel1, BoxLayout.PAGE_AXIS));
        panel1.setMinimumSize(PANEL1_SIZE);
        panel1.setPreferredSize(PANEL1_SIZE);
        panel1.setMaximumSize(PANEL1_SIZE);
        panel1.setBackground(Color.BLACK);
        //JPanel for Attack and Kick Buttons
        panel2 = new JPanel();
        panel2.setLayout(new BoxLayout(panel2, BoxLayout.LINE_AXIS));
        panel2.setMinimumSize(PANEL2_SIZE);
        panel2.setPreferredSize(PANEL2_SIZE);
        panel2.setMaximumSize(PANEL2_SIZE);
        panel2.setBackground(Color.BLUE);
        //JPanel for Power Attack Button
        panel3 = new JPanel();
        panel3.setLayout(new BoxLayout(panel3, BoxLayout.PAGE_AXIS));
        panel3.setMinimumSize(PANEL3_SIZE);
        panel3.setPreferredSize(PANEL3_SIZE);
        panel3.setMaximumSize(PANEL3_SIZE);
        panel3.setBackground(Color.ORANGE);
        panel3.add(Box.createHorizontalGlue());
        panel3.add(Box.createVerticalGlue());
        //JTextArea & JScrollPane
        output = new JTextArea();
        output.setEditable(false);
        JScrollPane outputScroller = new JScrollPane(output, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        outputScroller.setMaximumSize(new Dimension(375, 250));
        outputScroller.setBorder(BorderFactory.createLineBorder(Color.RED));
        panel1.add(outputScroller);
        panel1.add(Box.createHorizontalGlue());
        panel1.add(Box.createVerticalGlue());
        //Attack Button
        JButton attackButton = new JButton(" ATTACK ");
        attackButton.setMaximumSize(new Dimension(75, 30));
        attackButton.setBorderPainted(true);
        //Kick Button
        JButton kickButton = new JButton(" KICK ");
        kickButton.setMaximumSize(new Dimension(75, 30));
        kickButton.setBorderPainted(true);
        //Add components
        panel2.add(attackButton);
        panel2.add(Box.createHorizontalGlue());
        panel2.add(Box.createVerticalGlue());
        panel2.add(kickButton);
        panel2.add(Box.createHorizontalGlue());
        panel2.add(Box.createVerticalGlue());
        //Power Attack Button
        JButton powAttButton = new JButton(" POWER ATTACK ");
        powAttButton.setMaximumSize(new Dimension(150, 30));
        powAttButton.setBorderPainted(true);
        panel3.add(powAttButton);
        panel3.add(Box.createHorizontalGlue());
    }
    public void buildGUI() {
        //Add components and build GUI Frame
        this.add(panel3);
        this.add(panel2);
        this.add(panel1);
        //Set attributes
        //Pack components together inside of frame
        pack();
        //Center of screen
        setLocationRelativeTo(null);
        //Make frame visible
        setVisible(true);
    }
}

Answer 1

您必须设置PrimaryFrame的布局。我建议您在buildGUI()方法中添加一行：

public void buildGUI() {
        //defines the Layout for the main Frame
        this.setLayout(new GridLayout(3,1)) //its up to you wich Layout you use
        //Add components and build GUI Frame
        this.add(panel3);
        this.add(panel2);
        this.add(panel1);
        //Set attributes
        //Pack components together inside of frame
        pack();
        //Center of screen
        setLocationRelativeTo(null);
        //Make frame visible
        setVisible(true);
    }

注意，GridLayout(3,1)将生成一个具有三行一列的布局