java - GUI 未显示在我的屏幕上

Question

我以前曾在我的计算机上运行过 GUI，但通过这个程序，我想尝试实现 GridBag，这样我就可以制作一个简单的游戏。我不知道为什么它没有运行。这是代码:

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

public class GridBagTest extends JFrame{
    public static void main(String[] args){
        new GridBagTest();
    }

    public void GridBagTest(){
        JButton atk, mag, fort, pot1, pot2, flee;
        JPanel gamePanel = new JPanel();
        gamePanel.setLayout(new GridBagLayout());

        JFrame gameFrame = new JFrame("FightQuest"); 
        gameFrame.getContentPane().add(gamePanel);
        gameFrame.setSize(800, 600);
        gameFrame.pack();
        gameFrame.setVisible(true);

        atk = new JButton("Strike");
        mag = new JButton("Magic");
        fort = new JButton("Fortify");
        pot1 = new JButton("Potion 1");
        pot2 = new JButton("Potion 2");
        flee = new JButton("Flee");
        addItem(gamePanel, atk, 0, 0, 1, 1, GridBagConstraints.SOUTHEAST);
        addItem(gamePanel, mag, 1, 0, 1, 1, GridBagConstraints.SOUTH);
        addItem(gamePanel, fort, 2, 0, 1, 1, GridBagConstraints.SOUTHWEST);
        addItem(gamePanel, pot1, 0, 1, 1, 1, GridBagConstraints.NORTHEAST);
        addItem(gamePanel, pot2, 1, 1, 1, 1, GridBagConstraints.NORTH);
        addItem(gamePanel, flee, 2, 1, 1, 1, GridBagConstraints.NORTHWEST);

    }

    private void addItem(JPanel p, JComponent c, int x, int y, int width, int height, int align){
        GridBagConstraints gc = new GridBagConstraints();
        gc.gridx = x;
        gc.gridy = y;
        gc.gridwidth = width;
        gc.gridheight = height;
        gc.weightx = 100.0;
        gc.weighty = 100.0;
        gc.insets = new Insets(0, 0, 0, 0);
        gc.anchor = align;
        gc.fill = GridBagConstraints.NONE;
        p.add(c, gc);
    }
}

我不知道这是否有什么区别，但我从 Java 6 的 Java 引用书中获得了大部分代码，尽管我运行的是 Java 7，因为这是我学校的全部代码。我还在 XFCE 操作系统上编写所有代码。

Answer 1

更改此行

public void GridBagTest()

至

public GridBagTest()

构造函数没有返回类型。此外，您还应该在将组件添加到容器后调用 pack() 和 setVisible(true) 来调整和显示组件的大小。

另请注意，在这种情况下不需要扩展。

改变

public class GridBagTest extends JFrame

至

public class GridBagTest{

代码中显示的更改:

public class GridBagTest{
    public static void main(String[] args){
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new GridBagTest();
            }
        });
    }

    public GridBagTest(){
        JButton atk, mag, fort, pot1, pot2, flee;
        JPanel gamePanel = new JPanel();
        gamePanel.setLayout(new GridBagLayout());

        JFrame gameFrame = new JFrame("FightQuest"); 
        gameFrame.getContentPane().add(gamePanel);
        gameFrame.setSize(800, 600);


        atk = new JButton("Strike");
        mag = new JButton("Magic");
        fort = new JButton("Fortify");
        pot1 = new JButton("Potion 1");
        pot2 = new JButton("Potion 2");
        flee = new JButton("Flee");
        addItem(gamePanel, atk, 0, 0, 1, 1, GridBagConstraints.SOUTHEAST);
        addItem(gamePanel, mag, 1, 0, 1, 1, GridBagConstraints.SOUTH);
        addItem(gamePanel, fort, 2, 0, 1, 1, GridBagConstraints.SOUTHWEST);
        addItem(gamePanel, pot1, 0, 1, 1, 1, GridBagConstraints.NORTHEAST);
        addItem(gamePanel, pot2, 1, 1, 1, 1, GridBagConstraints.NORTH);
        addItem(gamePanel, flee, 2, 1, 1, 1, GridBagConstraints.NORTHWEST);
        gameFrame.pack();
        gameFrame.setVisible(true);

    }

    private void addItem(JPanel p, JComponent c, int x, int y, int width, int height, int align){
        GridBagConstraints gc = new GridBagConstraints();
        gc.gridx = x;
        gc.gridy = y;
        gc.gridwidth = width;
        gc.gridheight = height;
        gc.weightx = 100.0;
        gc.weighty = 100.0;
        gc.insets = new Insets(0, 0, 0, 0);
        gc.anchor = align;
        gc.fill = GridBagConstraints.NONE;
        p.add(c, gc);
    }
}

你会得到你的输出: