为什么不将java.awt.Image视为java.awt.Component？

Question

I was trying to switch the content of Panel between Component and Image, It works for the Component:

imgpanel.removeAll();
Component comp;
if ((comp = player.getVisualComponent()) != null) {
    imgpanel.add(comp);
}

Not for the Image:

btoi = new BufferToImage((VideoFormat) buf.getFormat());
img = btoi.createImage(buf);
imgpanel.removeAll();
imgpanel.add(img);//The method add(Component) in the type Container is not applicable for the arguments (Image)

What should I do here?

Answer 1

Why java.awt.Image is not considered as java.awt.Component ?

An Image extends Object . IE

• Object
  • Image

A Component also extends Object . IE

• Object
  • Component

Since neither Component extends Image , nor Image extends Component , neither has an is an relationship to the other. OTOH both have the is an relationship only with Object . IE Image is an Object & Component is an Object .

What should I do here?

Display the image in a Component designed to display images, such as (an ImageIcon in) a JLabel . So it might look like this:

panel.add( new JLabel( new ImageIcon(image) ) );

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For more details on this concept, see Inheritance in the 'Interfaces and Inheritance' section of the tutorial.