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我正在尝试使用 JFrame/JPanel 使用 Canvasto 转换游戏。以前我有 Game 对象 Extend Canvas 并实现 Runnable

然后创建一个 JFrame 并将其传递给画布......

以前是什么：（有效）

    public class Game extends Canvas implements Runnable{

    private void render() {
            // TODO Auto-generated method stub
            BufferStrategy bs = this.getBufferStrategy();

            if(bs==null){
                createBufferStrategy(3);
                return;
            }

            Graphics g = bs.getDrawGraphics();
            //////////////////////////////

            g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
            g.drawImage(background,0,0,null);
            p.render(g);
            c.render(g);
            //g.drawImage(player,100,100,this);

            //////////////////////////////
            g.dispose();
            bs.show();
        }

public static void main (String args[]){

        Game game = new Game();
        game.setPreferredSize(new Dimension(WIDTH*SCALE, HEIGHT*SCALE));
        game.setMaximumSize(new Dimension(WIDTH*SCALE, HEIGHT*SCALE));
        game.setMinimumSize(new Dimension(WIDTH*SCALE, HEIGHT*SCALE));

        JFrame frame = new JFrame(game.TITLE);
        frame.add(game);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

            game.start();
        }
}

但我想改为在 JPanel 上而不是 Canvas 上绘制图形，并将其传递给 JFrame .. 但它不起作用..

    public class Game extends JPanel implements Runnable{
        private void render() {
            // TODO Auto-generated method stub
            BufferStrategy bs = this.getBufferStrategy(); // error here

            if(bs==null){
                createBufferStrategy(3); //error here
                return;
            }

public static void main (String[] args){
Game game = new Game();
        game.setPreferredSize(new Dimension(WIDTH*SCALE, HEIGHT*SCALE));
        game.setMaximumSize(new Dimension(WIDTH*SCALE, HEIGHT*SCALE));
        game.setMinimumSize(new Dimension(WIDTH*SCALE, HEIGHT*SCALE));

        JFrame frame = new JFrame(game.TITLE);
        frame.add(game);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

    game.start();
}

    }


Exception in thread "Thread-1" java.lang.IllegalArgumentException: input == null!
at javax.imageio.ImageIO.read(Unknown Source)

使困惑...

4

1 回答 1

1

您拥有的代码甚至不应该编译。JPanel 没有公共getBufferStrategy()方法。所以你应该在这一行得到一个编译错误：

BufferStrategy bs = this.getBufferStrategy();

在 Swing 中，更典型的是在 JFrame 级别使用 BufferStrategy 。我认为可能只有重量级组件才能使用 BufferStrategy。

于 2013-07-08T18:51:54.190 回答