Question

是否可以在初始化后更改JPanel的图像？

Block.java（改变img的JPanel）

@SuppressWarnings("serial")
public class Block extends JPanel{

    private int rotation;

    public Block(){
    }

    @Override
    protected void paintComponent(Graphics g){ 
        super.paintComponent(g);    
        Graphics2D g2 = (Graphics2D) g;

        g2.drawImage(Images.greenBlock, 0, 0, null); 

    } 
}

现在我需要像changeImage：

这样的方法

...
JPanel xy = new Block();

xy.changeImage(newImg); //I know this method does NOT exist

感谢您的帮助

Answer 1

改变这个：

JPanel xy = new Block();

到此：

Block xy = new Block();

并使用Block changeImage(newImg)方法更改变量greenBlock引用的图像。在您的changeImage方法中，不要忘记致电repaint();

问题：为什么paintComponent方法中的break;语句？

如，

public class Block extends JPanel{

    private int rotation;
    // if you wish to initialize it with greenBlock...
    private Image myImage = Images.greenBlock;

    public Block(){
    }

    @Override
    protected void paintComponent(Graphics g){ 
        super.paintComponent(g);    
        Graphics2D g2 = (Graphics2D) g;
        g2.drawImage(myImage, 0, 0, null);
    } 

    public void changeImage(Image img) {
        this.myImage = img;
        repaint();
    }
}

如何更改JPanel的背景图片

1 个答案: