Question

老实说，我不知道自己做错了什么。（虽然我确定它有点相似。）我一直试图调整我的代码数小时无济于事。

我正在尝试剪切图片并显示它们。之后，我会随机定位它们所在的位置并尝试将它们放置在正确的位置。但是，现在，我的任何问题都出现在我的JPanel上。有一次，我的测试代码显示了图像。但是，现在，相同的测试代码不起作用。

如果你能看到我做错了什么/问题出在哪里，请告诉我。希望这是简单而愚蠢的事情。

import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.*;
import javax.imageio.*;
import javax.swing.*;

public class Lab10 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        MyFrame frame = new MyFrame();
        MyPanel panel = new MyPanel();
        frame.add(panel);
        panel.setFocusable(true);


    }

}

class MyFrame extends JFrame{
    MyFrame(){
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        setSize(800,800);
        setResizable(false);
    }
}

class MyPanel extends JPanel{
    public static final int SIZE = 4;
    private int oldx = -1;
    private int oldy = -1;
    private final String fileName = "houseTyrell.png";

    public ImageArray imageArray = new ImageArray(fileName, SIZE);

    MyPanel(){

        addMouseListener(new MouseAdapter(){

            public void mousePressed(MouseEvent e){
                if(e.getButton()==1){
                    if(oldx == -1){
                        oldx = e.getX();
                        oldy = e.getY();
                    }else{
                        //imageArray.swapPoints(oldx, oldy, e.getX(), e.getY());
                        oldx = -1;
                        oldy = -1;
                        repaint();
                    }
                }
            }
        });
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        imageArray.draw(g2);

        /*Image image2;
        try {
            image2 = ImageIO.read(new File("houseTyrell.png"));
            System.out.println("I should print");

            try{
                g2.drawImage(image2, 0, 0, null);
            } catch(Exception my){
                System.out.println("Drawing issue");
            }

        } catch (IOException ex) {
            System.out.println("Reading issue");

        }*/

    }
}


class ImageArray{
    private Square[][] squares;
    private String fileName;
    private int size;
    private int w;
    private int h;

    public ImageArray(String fileName, int size) {
        this.size = size;
        this.fileName= fileName;
        squares = new Square[size][size];
        try {
            BufferedImage image = ImageIO.read(new File(fileName));
            w = image.getWidth() / size;
            h = image.getHeight() / size;
            for (int row = 0; row < size; row++) {
                for (int col = 0; col < size; col++) {
                    squares[row][col] = new Square(
                    image.getSubimage(row * w , col * h , w, h), row, col, w, h);
                }
            }

        } catch (Exception e) {
            System.out.println("Can't open file!");
        }
        shuffle();
        } 

    //TODO
    public void shuffle(){
        for(int i = 0; i < size * size; i++){

        }
    }

    //TODO
    public void swapPoints(int oldx, int oldy, int newx, int newy){

    }

    public void draw(Graphics2D g2){
        for(int i = 0; i < squares.length; i++){
            for(int j = 0; j < squares[0].length; j++){
                Square square = squares[i][j];
                square.draw(g2);

            }
        }
    }

}

class Square{
    private BufferedImage image;
    private int row;
    private int col;
    private int x,y;
    private int w;
    private int h;

    Square(BufferedImage image, int row, int col, int w, int h){
        this.image = image;
        this.row = row;
        this.col = col;
        this.x = row * w;
        this.y = col * h;
        this.w = w;
        this.h = h;
    }

    public void draw(Graphics2D g2){
        try{
            g2.drawImage(image, x, y, null);
        } catch (Exception my){
            System.out.println("Square issue");
        }
    }

    public BufferedImage getImage(){
        return image;
    }

    public int getRow(){
        return row;
    }

    public int getCol(){
        return col;
    }
}

Answer 1

您在建立用户界面之前可以看到框架，在您添加invalidate之后尝试在框架上调用validate，repaint和panel ...

public static void main(String[] args) {
    MyFrame frame = new MyFrame();
    MyPanel panel = new MyPanel();
    frame.add(panel);
    panel.setFocusable(true);
    frame.invalidate();
    frame.validate();
    frame.repaint();

}

坦率地说，你的MyFrame课程做得很少（除了让你的生活变得更加艰难），我会考虑摆脱它，也许用一个生成器方法替换它，它会返回一个看不见的框架尚未...

您还应该在Event Dispatching Thread的上下文中创建UI，这有助于解决其他“奇怪”问题。

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) {
                ex.printStackTrace();
            }

            MyFrame frame = new MyFrame();
            MyPanel panel = new MyPanel();
            frame.add(panel);
            panel.setFocusable(true);
            frame.invalidate();
            frame.validate();
            frame.repaint();
        }
    });
}

有关详细信息，请参阅Initial Threads

Answer 2

在Class Lab10的主要方法中，在JFrame之前初始化JPanel，它应该可以工作。

PS：确保引用的图像＆＃34; houseTyrell.png＆＃34;临时存在或使用完全限定的路径进行测试（即c：//test//houseTyrell.png）。

图片没有显示在Swing中？

2 个答案: