call paintcomponent for a jpanel in jframe

Question

I have a JFrame with a JPanel on it ( JPanel is private in JFrame ). Now I want to override JPanel by using paintComponent method.

How can I do that?

Answer 1

When you create your instance of JPanel , (assuming you're doing it this way), do this:

JPanel panel = new JPanel(){
    @Override
    public void paintComponent(Graphics g){
       // paint code
    }
};

The other alternative is to create a private class which extends JPanel .
For example:

public class OuterClass{
    // fields, constructors, methods etc..

    private class MyPanel extends JPanel{   
       // fields, constructors, methods etc..

       @Override
       public void paintComponent(Graphics g){
          // paint code
       }

    }
}

Answer 2

从你的问题不清楚，但我认为没有什么复杂的覆盖了Swing JComponents的paintComponent ，请避免使用方法paint()为Swing JComponents ，只使用paintComponent()