如何在JFrame中将单个JPanel放大

Question

我正在做一个游戏，并且我的框架中有多个面板。 panel4应该包含我的轮子，问题是当我需要panel4大得多时，panel4与板上的所有其他面板的大小相同，因为我希望轮子的图片能够完全显示，因为它是站立着的，当我需要全部显示时，仅显示车轮的顶部。

 public static void setUp() throws IOException {        
    frame=new JFrame();
    frame.setLayout(new GridLayout(7,1));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLocation(290, 5);
    frame.setSize(1100, 1100);
    frame.setTitle("Wheel of fortune");

    final JPanel scorePanel=new JPanel();
    final JPanel namePanel=new JPanel();
    final JPanel panel=new JPanel(new GridLayout(1,3,1,1));
    final JPanel panel1=new JPanel();
    final JPanel panel2=new JPanel();
    final JPanel panel3=new JPanel(new GridLayout(2,1,1,1));

    panel3.add(new JLabel("Dead letters/phrases:"));
    panel3.add(LettersOrPhGuessed);

    scorePanel.add(new JLabel("Score Board:"));


    final WheelGui test = new WheelGui();
    final JPanel panel4=test;
    panel4.setSize(800, 600);//this does nothing in the program


    namePanel.add(playerName);
    frame.getContentPane().add(namePanel);
    frame.getContentPane().add(scorePanel);
    frame.getContentPane().add(panel);
    frame.getContentPane().add(panel4);
    frame.getContentPane().add(panel2);
    frame.getContentPane().add(panel1);
    frame.getContentPane().add(panel3);
    frame.setVisible(true);
}

这是我构建panel4的本质的地方。 我试图使此面板变大，但是当我这样做时，屏幕上似乎没有任何反应。 任何建议都很好。

@SuppressWarnings("serial")
public class WheelGui extends JPanel{
ImageIcon image = new ImageIcon("WheelofFortune.JPG");    
JPanel rotationPanel;  
final int WIDTH = 800;  
final int HEIGHT = 600;  
static double degrees;  

public WheelGui()  
{  
    super();
    this.setPreferredSize(new Dimension(WIDTH,HEIGHT));  
    setBackground(Color.lightGray);  
    setLayout(null);  
    setFocusable(true);  
    rotationPanel = new JPanel(); 

    rotationPanel = new turningCanvas();  
    rotationPanel.setPreferredSize(new Dimension(image.getIconWidth(),image.getIconHeight()));  
    //rotationPanel.setSize(800,600);  
    add(rotationPanel);  
    rotationPanel.setBounds(WIDTH/8, HEIGHT/8, rotationPanel.getPreferredSize().width, rotationPanel.getPreferredSize().height);  
    degrees = 0;  
}  
public void paintComponent (Graphics g)  
{  
    super.paintComponent(g);  
}  
public class turningCanvas extends JPanel  
{  
    public void paintComponent (Graphics g)  
    {  
        super.paintComponent(g);  
        Graphics2D g2d = (Graphics2D)g;  
        g2d.rotate(Math.toRadians(degrees),image.getIconWidth()/2,image.getIconHeight()/2);  
        image.paintIcon(this, g2d, 0, 0);  

    }  
}   
public void rotate(){
    for(int i=0;i<360;i+=4){
        degrees++;
        repaint();
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 1

你有很多问题...

首先，您正在使用GridLayout 。 GridLayout将以网格模式布置所有组件，并根据父容器的宽度和高度为每个组件分配相同的空间。 如果您希望组件具有不同的大小，则GridLayout并不是最佳选择。

其次，您正在使用setPreferredSize 。 这是一种不好的做法，因为您无法避免应用程序的其他部分稍后会尝试更改组件的大小。

相反，您应该尽可能覆盖getPreferredSize方法。

就个人而言，我建议使用GridBagLayout ，但您可能想查看《布局管理器的视觉指南》以了解其他选择。

用示例更新

我知道要执行的操作的唯一方法是使用GridBagLayout ，它使您可以灵活地定义各个组件从可用空间中将占用多少空间。 它是最灵活，最困难的布局管理者之一。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;

public class TestLayout25 {

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }
                try {
                    setUp();
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
        });
    }

    public static void setUp() throws IOException {
        JFrame frame = new JFrame();
        frame.setLayout(new GridBagLayout());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 400);
        frame.setLocationRelativeTo(null);
        frame.setTitle("Wheel of fortune");

        final JPanel scorePanel = new JPanel();
        final JPanel namePanel = new JPanel();
        final JPanel panel = new JPanel(new GridLayout(1, 3, 1, 1));
        final JPanel panel1 = new JPanel();
        final JPanel panel2 = new JPanel();
        final JPanel panel3 = new JPanel(new GridLayout(2, 1, 1, 1));

        panel3.add(new JLabel("Dead letters/phrases:"));
        panel3.add(createPane(Color.RED));

        scorePanel.add(new JLabel("Score Board:"));


        final WheelGui test = new WheelGui();
        final JPanel panel4 = test;
        panel4.setSize(800, 600);//this does nothing in the program

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        gbc.weightx = 1;
        gbc.fill = GridBagConstraints.HORIZONTAL;

        namePanel.add(new JLabel("Blue"), gbc);
        frame.getContentPane().add(namePanel, gbc);
        frame.getContentPane().add(scorePanel, gbc);
        frame.getContentPane().add(panel, gbc);
        gbc.weighty = 1;
        gbc.fill = GridBagConstraints.BOTH;
        frame.getContentPane().add(panel4, gbc);
        gbc.weighty = 0;
        gbc.fill = GridBagConstraints.HORIZONTAL;
        frame.getContentPane().add(panel2, gbc);
        frame.getContentPane().add(panel1, gbc);
        frame.getContentPane().add(panel3, gbc);
        frame.setVisible(true);
    }

    protected static JPanel createPane(Color color) {

        JPanel panel = new JPanel();
        panel.setBorder(new LineBorder(color));
        return panel;

    }

    public static class WheelGui extends JPanel {

        ImageIcon image = new ImageIcon("WheelofFortune.JPG");
        JPanel rotationPanel;
        final int WIDTH = 800;
        final int HEIGHT = 600;
        static double degrees;

        public WheelGui() {
            super();
            this.setPreferredSize(new Dimension(WIDTH, HEIGHT));
            setBackground(Color.lightGray);
            setLayout(null);
            setFocusable(true);
            rotationPanel = new JPanel();

            rotationPanel = new turningCanvas();
            rotationPanel.setPreferredSize(new Dimension(image.getIconWidth(), image.getIconHeight()));
            //rotationPanel.setSize(800,600);  
            add(rotationPanel);
            rotationPanel.setBounds(WIDTH / 8, HEIGHT / 8, rotationPanel.getPreferredSize().width, rotationPanel.getPreferredSize().height);
            degrees = 0;
        }

        public void paintComponent(Graphics g) {
            super.paintComponent(g);
        }

        public class turningCanvas extends JPanel {

            public void paintComponent(Graphics g) {
                super.paintComponent(g);
                Graphics2D g2d = (Graphics2D) g;
                g2d.rotate(Math.toRadians(degrees), image.getIconWidth() / 2, image.getIconHeight() / 2);
                image.paintIcon(this, g2d, 0, 0);

            }
        }

        public void rotate() {
            for (int i = 0; i < 360; i += 4) {
                degrees++;
                repaint();
                try {
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}

Answer 2

您正在使用GridLayout。 布局会照顾每个组件的大小和位置，因此您几乎无能为力。

GridLayout对象将组件放置在单元格的网格中。 每个组件占用其单元中的所有可用空间，并且每个单元的大小完全相同。

您将不得不使用其他布局。 GridBagLayout可能有用。