Cannot draw and paint various shapes on GUI in Java

Question

So I am trying to figure out why my GUI isn't drawing and coloring my shapes.

Basically, I have to draw and color various shapes. Shapes are generated upon pressing a JButton on the GUI and stored in a List. However, I am unable to draw each shape. I changed the implementation inside of paintComponent so that it would iterate over my list of shapes.

I believe my problem lies within this class, which is responsible for creating the GUI, making the shapes, and painting them:

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class MyPanel extends JPanel{
    
    private List<Shape> shapes = new ArrayList<Shape>();
    final int SIZE = 6;
    
    public void paintComponent(Graphics g) {
          super.paintComponents(g);
          Graphics2D g2d = (Graphics2D) g;
              
          for (Shape shape: shapes) {
              g2d.setColor(shape.getColor());
              shape.drawShape(g2d);
          }
        
    }
    
    public static void main (String[] args) {

        JButton loading = new JButton("Load shapes");
        JPanel panel = new JPanel();
        JFrame frame = new JFrame("Display shapes");
        
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(panel);
        frame.setSize(600, 600);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        
        loading.addActionListener(new ActionListener()
                {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        // TODO Auto-generated method stub
                        new MyPanel().generateAllShapes();
                    }
                });
        
        panel.add(loading);
    }
    
    public void generateAllShapes() {
        shapes = new ArrayList<Shape>();
        
        ShapeFactory sf = new ShapeFactory();
        for (int i = 0; i < SIZE; i++) {
            shapes.add(sf.generateShape());
        }
        sf.spaceShapes(shapes);
    }
}

This is my drawShape method in one of my other classes:

    @Override
    public void drawShape(Graphics form) {
        // TODO Auto-generated method stub
        form.drawRect(upperX, upperY, width, length);
        form.fillRect(upperX, upperY, width, length);

I omitted the other classes but they are just basic implementations of various shape classes as well as the abstract Shape class they extend from. I have a simple ShapeFactory class which just basically generates a random shape as well as a random color for it.

Here's a recent [Stack Overflow answer](https://stackoverflow.com/questions/69121260/java-swing-rendering-issue-empty-spaces-doubled-rendering/69122544#69122544) where I draw various shapes on a drawing JPanel. You can start with that code and slowly, carefully, add features, being sure to thoroughly test each new feature. — Gilbert Le Blanc, Oct 04 '21 at 20:16
*"This is my drawShape method in one of my other classes:"* For better help sooner, [edit] to add a single [mre]. — Andrew Thompson, Oct 04 '21 at 20:56
As mentioned before by MadProgrammer you're overriding `MyPanel`'s `paintComponent(...)` method but never adding it to the frame, instead of `panel` you should be using `this.add(loading)` and `frame.add(this)`, but as well as Gilbert I have 2 very detailed answers which you can also check to draw different shapes: [example](https://stackoverflow.com/a/41944799/2180785) and [example](https://stackoverflow.com/a/42167399/2180785). Also don't forget to add `@Override` for `paintComponent(...)` method — Frakcool, Oct 04 '21 at 22:27
Thanks for all the responses. I did made some changes and are reading the posts from your comments. I'll slowly build my class based on everything here. — amiteur, Oct 04 '21 at 23:44

Cannot draw and paint various shapes on GUI in Java

0 Answers0