JFrame 中的 Spritesheet 动画

Question

我正在尝试使用 JFrame 中的 spritesheet 获取动画。问题是一旦加载，图像就不会改变。它只显示第一张图片。 我进行了很多搜索并尝试了几乎所有的建议，但无法让它发挥作用。

顺便说一下，getSprite 的返回类型是 Image。 当我在 JFrame 中执行所有操作时，只显示一张图像。当我在扩展 JPanel 的单独类中执行此操作时，我只得到一个白色窗口。

更新 1：感谢 andrew，让 JFrame 正常工作。也修复了我的旧部分。这是工作的code at ideone

更新 2： 这是我的带有计时器的版本。

class TestSpriteSheet extends JFrame{

   //same old variables

    public TestSpriteSheet(){
        //same old stuff goes here before this
        add(new PanelSprite(this, ss));
        this.setVisible(true);
    }
}

class PanelSprite extends JPanel{

    private long runningTime = 0;
    private int fps = 3;
    private boolean stop = false;
    private SpriteSheetManager ss;
    private TestSpriteSheet temp;

    public PanelSprite(TestSpriteSheet test, SpriteSheetManager sm){
        ss = sm;
        temp = test;
        setSize(180,180);
        setLayout(new BorderLayout()); init();
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        long time = 5000; 
        animate_with_gfx(g, time);
    }

    public void init(){
        Timer t = new Timer((int)(1000/fps), new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if(!stop) {
                    repaint();
                } else {
                    ((Timer)e.getSource()).stop();
                }
            }
        });
        t.setRepeats(true);
        t.setDelay((int)(1000/fps));
        t.start();
    }

    public void animate_with_gfx(Graphics g, long time){
        if(runningTime <= time){
            try {
                System.out.println(runningTime); //Checking if this part works
                int x = 0; int y = 0;
                g.drawImage(ss.getSprite(x, y), 40, 40, null);
                x++; y++; runningTime+=(1000/fps);
            }catch (Exception ex) {
                ex.printStackTrace();
            }
        }
        else{
            stop = true;
        }
    }
}

Answer 1

public void paintComponent(Graphics g){
    super.paintComponent(g);
    long time = 5000; int fps = 3;
    boolean stop = false;
    Timer t = new Timer((int)(1000/fps), new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            if(!stop) {
                animate_with_gfx(g, time, fps, stop);
                repaint();
            } else {
                ((Timer)e.getSource()).stop();
            }
        }
    });
    t.setRepeats(true);
    t.setDelay((int)(1000/fps));
    t.start();
    System.exit(0);
}

这部分是完全错误的，因为只要 JRE 认为视图需要重新绘制，就会调用 paintComponent() 方法。所以一定要删除System.exit(0);！

那么 Timer 需要一个实例，才能启动一次。这最好在构造函数或init() 类型方法中完成。

它可能看起来像这样：

private int fps = 3;
private boolean stop = false;

public void paintComponent(Graphics g){
    super.paintComponent(g);
    long time = 5000;
    animate_with_gfx(g, time, fps, stop);
}

/** Called from constructor..  */
public void init(){
    Timer t = new Timer((int)(1000/fps), new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            if(!stop) {
                repaint();
            } else {
                ((Timer)e.getSource()).stop();
            }
        }
    });
    t.setRepeats(true);
    t.setDelay((int)(1000/fps));
    t.start();
}

更新

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

import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;

class SpriteSheetManager {

    private BufferedImage spriteSheet;
    int cols;
    int rows;

    public SpriteSheetManager() {
        setSpriteSheet();
    }

    public void setSpriteSheet() {
        try {
            spriteSheet = ImageIO.read(
                    new URL("http://s8.postimg.org/vso6oed91/spritesheet.png"));
            setColsAndRows(3, 3);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public BufferedImage getSpriteSheet() {
        return spriteSheet;
    }

    public void setColsAndRows(int cols, int rows) {
        this.cols = cols;
        this.rows = rows;
    }

    public Image getSprite(int x, int y) {
        Image sprite = null;
        try {
            sprite = spriteSheet.getSubimage(
                    x * spriteSheet.getWidth() / cols,
                    y * spriteSheet.getHeight() / rows,
                    spriteSheet.getWidth() / cols,
                    spriteSheet.getHeight() / rows);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sprite;
    }
}

class Ideone {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TestSpriteSheet();
            }
        });
    }

}

class TestSpriteSheet extends JFrame {

    private static final long serialVersionUID = 1L;
    private SpriteSheetManager ss;

    public TestSpriteSheet() {
        super("Testing SpriteSheets");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        setLayout(new BorderLayout());
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent windowEvent) {
                System.exit(0);
            }
        });

        ss = new SpriteSheetManager();

        add(new PanelSprite(this, ss));
        pack();
        setSize(200, 200);
        this.setVisible(true);
    }
}

class PanelSprite extends JPanel {

    private long runningTime = 0;
    private int fps = 10;
    private boolean stop = false;
    private SpriteSheetManager ss;
    private TestSpriteSheet temp;
    private Timer t;
    int count = 0;
    long time = 50000;

    public PanelSprite(TestSpriteSheet test, SpriteSheetManager sm) {
        ss = sm;
        temp = test;
        init();
    }

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

    public void init() {
        t = new Timer((int) (1000 / fps), new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (!stop) {
                    repaint();
                } else {
                    ((Timer) e.getSource()).stop();
                }
            }
        });
        t.setRepeats(true);
        t.setDelay((int) (1000 / fps));
        t.start();
    }

    public void animate_with_gfx(Graphics g) {
        if (runningTime <= time) {
            Image img = ss.getSprite((count % 9) % 3, (count % 9) / 3);
            g.drawImage(img, 40, 40, this);
            count++;
            runningTime += (1000 / fps);
        } else {
            stop = true;
        }
    }
}