Thread: JOptionPane problem

Move the call to JOptionPane outside of the paintComponent method.
The paint method should only do the drawing. What it is to draw should be determined outside of paint and then repaint called which will cause paint method to be called where the drawing can be done.

That makes sense but how do I pass interval to paintComponent so that it knows what do draw?

Make it a class variable that the paintComponent can see.

ok so I think I did what you said and it's still giving me the same problem... here's the code:

import java.util.*;
import java.lang.*;
import javax.swing.*;
import java.awt.*;
 
public class curveApprox
{
	public static void main(String[] args)
	{
		JFrame frame = new JFrame("Circle Approximator");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
		myPanel panel = new myPanel();
		frame.add(panel);
		frame.setSize(500,500);
		frame.setVisible(true);
	}
}
 
class Global
{
	Scanner scanner = new Scanner(System.in);
	public static String input = JOptionPane.showInputDialog("Choose the interval t in radians");
	public static double interval = Double.parseDouble(input);
}
 
 
class myPanel extends JPanel
{
 
	public void paintComponent(Graphics g)
	{
		g.drawLine(250,0,250,500); //x-axis
		g.drawLine(0,250,500,250); //y-axis
 
		double interval = Global.interval;
 
		for (double t = 0;t<2*Math.PI;)
		{
			double x0 = t;
			double y0 = t;
			double x1 = t+interval;
			double y1 = t+interval;
			g.drawLine((int)(200*Math.cos(x0)+(250)),(int)(200*Math.sin(y0)+250),(int)(200*Math.cos(x1)+250),(int)(200*Math.sin(y1)+250));
			t += interval;
		}
	}
}

What is the "same" problem? I don't see an error message in your post?
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Your code is still calling the JOptionPane from code within the paintComponent method.
Move this line to the class level:
double interval = Global.interval;

"Move this line to the class level" -I don't know what you mean by this

and the problem isn't an error message; the code compiles fine but if you look at my original post you will see the picture i posted of the output... that is the problem

Oh wait I got it now, put double interval = Global.interval in the class myPanel before the method definition right? It's working fine now, thanks for the help