java - 将对象内部的 ImageIcon 添加到另一个类中的框架

Question

public class Dog {

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        ImageIcon image = new ImageIcon("dog.jpg");
        image.paintIcon(this,g,200,0);
    }

    public class Gui extends JFrame {
        Frame frame = new Frame();
        Dog dog = new Dog();
        frame.add(dog.paintComponent(??));
    }
}

因此狗对象的绘制组件的方法将被添加到 JFrame 或 JPanel 中。

这是正确的方法还是您需要调用 repaint() 函数？

Answer 1

IS this the right way of going about it or do you need to call the repaint() function

不幸的是，这不是正确的方法。 paintComponent(g) 应该被覆盖。您需要将 Dog 类扩展为 JComponent 或 JComponent 的子类之一，然后重写 paintComponent(g):

class Dog extends JComponent{
    @Override
    paintComponent(Graphics g){
        //your codes..
    } 
}

但是，如果您只想创建一个可以使用自定义绘画进行绘制的 Dog 对象，则不需要 paintComponent() 方法。您可以简单地为其创建一个 draw() 方法:

class Dog{

    private ImageIcon image;

    public Dog(){
        java.net.URL imgUrl = getClass().getResource("dog.jpg");
        image= new ImageIcon(imgUrl);
    }

    public void draw(Graphics g){
        g.drawImage(image.getImage(), x, y, width, height, null);
    }

}

当您想在 Canvas 或面板中绘制狗时:

public class DrawingSpace extends JPanel
{
    private Dog dog;

    public DrawingSpace(){
        dog = new Dog();
    }

    @Override
    protected void paintComponent(Graphics g){
        super.paintComponent(g);
        dog.draw(g);   //will invoke Dog's draw method and draw a dog
    }
}