不能集中JButtons

Question

我需要一些帮助集中我的JButtons。现在，它们水平居中，但它们拒绝垂直居中。这是两个类Game和Menu的代码。另外，无论如何使用blocklayout在我的按钮之间放置空格。

游戏类：

package main;
import java.awt.*;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Game extends JFrame{

    private static final long serialVersionUID = -7071532049979466544L;
    public static final int WIDTH = 1280, HEIGHT = WIDTH/12 * 9;
    private Handler handler;
    public STATE state = STATE.Menu;
    JPanel screen;

    //State of the game
    public enum STATE{
        Menu,
        DeckConstructor,
        Game;
    }

    //Game Launch
    public Game() {

        screen = new JPanel(new CardLayout());
        screen.add(new Menu(this).getMenu(), "MENU");
        screen.add(new DeckConstructor(this).getDeckConstructor(), "DECK_CONSTRUCTOR");

        getContentPane().add(screen,BorderLayout.CENTER);
        setPreferredSize(new Dimension(WIDTH, HEIGHT));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        pack();
        setVisible(true);

    }

    public static void main(String[]args){
        new Game();
    }
}

菜单类：

package main;
import java.awt.event.*;
import java.awt.*;

import javax.swing.*;
import javax.swing.border.EmptyBorder;


public class Menu extends JFrame implements ActionListener{

    private JPanel buttonPanel;
    private JButton play;
    private JButton deckConstructor;
    private JButton quit;
    private Game game;


    public Menu(Game game){
        this.game = game;
        buttonPanel = new JPanel();

        play = new JButton("Play");
        play.addActionListener(this);
        deckConstructor = new JButton("Deck Constructor");
        deckConstructor.addActionListener(this);
        quit = new JButton("Quit");
        quit.addActionListener(this);

        buttonPanel.add(play);
        buttonPanel.add(deckConstructor);
        buttonPanel.add(quit);
        buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.Y_AXIS));
        play.setAlignmentX(Component.CENTER_ALIGNMENT);
        deckConstructor.setAlignmentX(Component.CENTER_ALIGNMENT);
        quit.setAlignmentX(Component.CENTER_ALIGNMENT);

    }

    public JPanel getMenu(){
        return buttonPanel;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        if(deckConstructor.equals((JButton) e.getSource())){
            CardLayout c1 = (CardLayout)(game.screen.getLayout());
            c1.show(game.screen, "DECK_CONSTRUCTOR");
        }

    }
}

Answer 1

我使用GridBagLayout和GridBagConstraints。

而不是BoxLayout

<强>代码：

public Menu(Game game) {
    this.game = game;
    buttonPanel = new JPanel(new GridBagLayout());

    play = new JButton("Play");
    play.addActionListener(this);

    deckConstructor = new JButton("Deck Constructor");
    deckConstructor.addActionListener(this);

    quit = new JButton("Quit");
    quit.addActionListener(this);

    GridBagConstraints c = new GridBagConstraints();
    c.gridx = 0;
    c.gridy = 0;
    c.anchor = GridBagConstraints.CENTER;
    // top, left, bottom, right
    c.insets = new Insets(0, 0, 50, 0);
    buttonPanel.add(play, c);

    c = new GridBagConstraints();
    c.gridx = 0;
    c.gridy = 1;
    c.anchor = GridBagConstraints.CENTER;
    // top, left, bottom, right
    c.insets = new Insets(0, 0, 50, 0);
    buttonPanel.add(deckConstructor, c);

    c = new GridBagConstraints();
    c.gridx = 0;
    c.gridy = 2;
    c.anchor = GridBagConstraints.CENTER;
    buttonPanel.add(quit, c);
}

为了使它居中，我使用GridBagConstraints#anchor并添加间距， 我使用了GridBagConstraints#insets。

原始框架：

使用GridBagLayout的框架：