Question

I made my own Component, named it ‘hi’ and put it in a JPanel and then put that JPanel into a JFrame, but nothing shows up. I made a border around JPanel to see if JPanel is even on the JFrame and sure enough, it is there, but my Component ( which by the way draws arcs) isn’t on the JPanel.

    JFrame frame = new JFrame();
    JPanel panel = new JPanel();


    final int FRAME_WIDTH  = 400;
    final int FRAME_HEIGHT = 400;

    testComponent hi = new testComponent();
    panel.add(hi);
    frame.add(panel);
    panel.setBorder(BorderFactory.createLineBorder(Color.red));        



    frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);

Thats what i have in the main, which is the basically the only thing in my test class. The testComponent() just has a paintComponent() that draws.

and the Component

public void paintComponent(Graphics g){
    Graphics2D g2 = (Graphics2D) g;
    g2.draw(new Arc2D.Double(100,100,100,100,0,30,Arc2D.PIE));
    g2.fill(new Arc2D.Double(100,100,100,100,30,330,Arc2D.PIE));
}

Like to note that, things like JButton, JTextField, etc. These work dandy in the JPanel

Answer 1

Try this code:

import javax.swing.*;
import java.awt.geom.*;
import java.awt.*;
public class PaintComponent extends JPanel
{
    public PaintComponent()
    {
        setPreferredSize(new Dimension(400,400));
    }
    public void paintComponent(Graphics g)
    {
        Graphics2D g2d = (Graphics2D)g;
        g2d.draw(new Arc2D.Double(100,100,100,100,0,30,Arc2D.PIE));
        g2d.fill(new Arc2D.Double(100,100,100,100,30,330,Arc2D.PIE));
    }
}

==============================================================================

import javax.swing.*;
import java.awt.*;
public class MainClass
{
    public static void main(String[] args)
    {
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        final int FRAME_WIDTH  = 400;
        final int FRAME_HEIGHT = 400;
        PaintComponent hi = new PaintComponent();
        panel.add(hi);
        frame.add(panel);
        panel.setBorder(BorderFactory.createLineBorder(Color.red));
        frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.pack();
    }
}