调整JFrame的大小以适合调整后的JPanel

yoavp13 发表于 Dev

yoavp13

我对JPanel和JFrame很陌生，可能无法按我应该的方式使用它们。我正在尝试创建Pong游戏，并在创建JFrame并将其添加到JPanel之后，我能够调整JPanel的大小，但是我不知道如何调整JFrame的大小以适合它。游戏类扩展了JPanel。

主要的：

    public static void main(String[] args) throws InterruptedException {
        int height = 500, width =(int) (height*1.56); //height = 500, width = 780;
        JFrame frame = new JFrame("Pong");
        Game game = new Game();
        frame.add(game);
        frame.setVisible(true);
        game.setSize(width, height);
        System.out.println(game.getHeight());
        System.out.println(game.getWidth());
        game.setBackground(Color.BLACK);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        System.out.println(frame.getHeight());
        System.out.println(frame.getWidth());
    }

输出：

输出应该是这样的：

500
780
*above* 500
*above* 780

编辑：

    public static void main(String[] args) throws InterruptedException {
        int height = 500, width =(int) (height*1.56); //height = 500, width = 780;
        JFrame frame = new JFrame("Pong");
        Game game = new Game();
        frame.add(game);
        frame.setVisible(true);
        game.setPreferredSize(new Dimension(width, height));
        frame.pack();
        System.out.println(game.getHeight());
        System.out.println(game.getWidth());
        game.setBackground(Color.BLACK);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        System.out.println(frame.getHeight());
        System.out.println(frame.getWidth());
    }

将setSize更改为setPreferredSize，然后为JFrame调用pack（）修复了所有问题。

充满鳗鱼的气垫船

同样，处理首选大小，并确保在添加组件后调用pack()JFrame 。另外，最好重写getPreferredSize而不是调用。例如：setPreferredSize

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

public class Game extends JPanel {
    private static final int PREF_W = 400;
    private static final int PREF_H = 300;
    private int prefW;
    private int prefH;

    public Game(int prefW, int prefH) {
        this.prefW = prefW;
        this.prefH = prefH;
    }

    public Game() {
        this(PREF_W, PREF_H);
    }

    @Override
    public Dimension getPreferredSize() {
        if (isPreferredSizeSet()) {
            return super.getPreferredSize();
        }
        return new Dimension(prefW, prefH);
    }

    private static void createAndShowGui() {
        int height = 500; 
        int width =(int) (height*1.56); //height = 500, width = 780;

        Game game = new Game(width, height);

        JFrame frame = new JFrame("Game");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.getContentPane().add(game);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);

        System.out.println("Frame size: " + frame.getSize());
        System.out.println("game size: " + game.getSize());
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}