CODEWITHSUNDEEP
javaswinguser-interfacejframejpanel
akolangto
akolangto

Reputation: 33

The method is undefined for the type JPanel

So I am trying to create a simple program that prints out a rectangle but I am having this problem and I don't know how to fix it. Here is my code:

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.*;

public class GraphicsEditor extends JPanel{
    
    public void drawShape(Graphics g) {
        super.drawShape(g);
        g.setColor(Color.BLUE);
        g.drawRect(100, 100, 120, 150);
    }
    
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        
        GraphicsEditor ga = new GraphicsEditor();
        
        frame.setSize(1280, 720);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
        frame.add(ga);
    }

}

The error is when I am trying to add the super in here:

public void drawShape(Graphics g) {
            super.drawShape(g);
            g.setColor(Color.BLUE);
            g.drawRect(100, 100, 120, 150);
        }

Upvotes: 1

Views: 900

Answers (1)

Andrew Thompson
Andrew Thompson

Reputation: 168825

A JPanel has no drawShape(Graphics) method, so calling the 'super' method makes no sense. When you think you're overriding a method, be sure to add the @Override notation to get a compiler warning when the method is incorrectly spelled, uses the wrong arguments, or is just entirely non-existent (as is the case here).

The correct way to go about this is to override the paintComponent method, call the (existing) super method, then immediately call the drawShape method with the Graphics instance provided to the paintComponent method.

This is the result when the GUI is shrunk down:

enter image description here

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.*;

public class GraphicsEditor extends JPanel {
    
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        drawShape(g);
    }
    
    // @Override // does NOT override an existing method! 
    public void drawShape(Graphics g) {
        //super.drawShape(g);
        g.setColor(Color.BLUE);
        g.drawRect(100, 100, 120, 150);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();

        GraphicsEditor ga = new GraphicsEditor();

        frame.setSize(280, 200);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(ga);
    }
}

Upvotes: 1

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