Circle Drawing Program

[SterAllures]

Hiya,

I have to make a program for a school assignment that draws a x number of ovals when you type in a number in a JTextfield.

Normally I know how to do it. But I have to do it in 3 different classes, a class Main, MyFrame and MyPanel.

Now I don't know how to draw the circles in the MyFrame class with a for loop in the ActionListener.

This is what I got so far.

(Made this in Netbeans so that's where the package is for)

Main

package week4;


//import javax.swing.UIManager;

public class Main
{
    public static void main(String[] arg)
    {
       //UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

        new MyFrame();
    }

} 

MyFrame

package week4;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;



public class MyFrame extends JFrame implements ActionListener
{

    private MyPanel mp;
    public JTextField tf;
    private JButton b1;


    public MyFrame()
    {
        mp = new MyPanel();
        tf = new JTextField(20);

        Container c = getContentPane();
        c.add(mp, BorderLayout.CENTER);
        JPanel p = new JPanel();
        p.add(tf);
        tf.addActionListener(this);
        c.add(p, BorderLayout.SOUTH);
        
        pack();
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
        public void actionPerformed(ActionEvent e)
        {
  
        }
        

} 

MyPanel

package week4;
import java.awt.*;
import javax.swing.*;


public class MyPanel extends JPanel
{
    public MyPanel()
    {
        setBackground(Color.WHITE);
        setPreferredSize(new Dimension(900, 1000));

    }

    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
    }

    
} 

Hope someone got an answer for me !

[wim DC]

Not much has to be changed really.

I added this to the actionperformed:

public void actionPerformed(ActionEvent e)
        {
            mp.drawCircles(Integer.parseInt(tf.getText()));
        }

And a bit to the MyPanel:

public class MyPanel extends JPanel
{
    int number;
    Random random;
    
    public MyPanel()
    {
        setBackground(Color.WHITE);
        setPreferredSize(new Dimension(800, 800));
        random = new Random();
    }

    public void paintComponent(Graphics g)
    {
        for(int i=0 ; i<number ; i++){
            g.fillOval(random.nextInt(780), random.nextInt(780), 10, 10);
        }

    }

    public void drawCircles(int n) {
        number=n;
        paintComponent(this.getGraphics());
    }
}

I think you'll figure it out what i changed and why... seems straightforward to me

Actionperformed triggers if you enter in the TextField. No error handling is in there, so if you don't enter an integer it'll get messy

[SterAllures]

Hey Oxano,

Thanks for that I've looked through it and Understand most of it, thanks for that!

But I think I explained it a bit wrong.

I have to create a program that draws a number of Circles horizontal next to eachother. so the amount I fill in in the JTextfield has to be the number of Circles.

It looks like this



What I changed and got so far is this(due to your help ):


Main

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package week4;

/**
 *
 * @author i7-Mel
 */
//import javax.swing.UIManager;

public class Main
{
    public static void main(String[] arg)
    {
       //UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

        new MyFrame();
    }

} 

MyFrame

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package week4;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.geom.*;

/**
 *
 * @author MelvinBlokhuijzen
 */


public class MyFrame extends JFrame implements ActionListener
{

    private MyPanel mp;
    public JTextField tf;


    public MyFrame()
    {
        mp = new MyPanel();
        tf = new JTextField(20);

        Container c = getContentPane();
        c.add(mp, BorderLayout.CENTER);
        JPanel p = new JPanel();
        p.add(tf);
        tf.addActionListener(this);
        c.add(p, BorderLayout.SOUTH);
        
        pack();
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
        public void actionPerformed(ActionEvent e)
        {
        mp.drawCircles(Integer.parseInt(tf.getText()));
        }
        

} 

MyPanel

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package week4;
import java.awt.*;
import javax.swing.*;
import java.util.Random;


/**
 *
 * @author MelvinBlokhuijzen
 */
public class MyPanel extends JPanel
{
    int number;


    public MyPanel()
    {
        setBackground(Color.WHITE);
        setPreferredSize(new Dimension(800, 800));
    }

    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        for (int regel = 1 ; regel <= 4 ; regel++ )
                {
            for ( int hori = 1 ; hori <= 6 ; hori++)
                        {
                g.drawOval(50, 50, 100, 100);
            }
                }

        
        
        /*for(int i=0 ; i<number ; i++)
        {
            g.drawOval(100, 100, 50, 50);
        }*/
    }

    public void drawCircles(int n)
    {
        number=n;
        paintComponent(this.getGraphics());
    }

} 

The problem I'm having is how to draw multiple Circles with the amount you fill in in the JTextfield.
Also the screen has to exactly stop at the last Horizontal circle with the getWidth() and pack() commands.

Any Ideas?

[wim DC]

This will do the trick

import java.awt.*;
import javax.swing.*;
import java.util.Random;


/**
 * @author MelvinBlokhuijzen
 */
public class MyPanel extends JPanel {
    int number;
    int x, y;
    int circleDiameter = 400;


    public MyPanel() {
        setBackground(Color.WHITE);
        setPreferredSize(new Dimension(800, 800));
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (int regel = 0, total = 0; regel < y + 1 && total < number; regel++) {
            for (int hori = 0; hori < x && total < number; hori++) {
                g.drawOval((hori * circleDiameter), (regel * circleDiameter), circleDiameter, circleDiameter);
                total++;
            }
        }


        /*for(int i=0 ; i<number ; i++)
        {
            g.drawOval(100, 100, 50, 50);
        }*/
    }

    public void drawCircles(int n) {
        number = n;
        x = this..getWidth() / circleDiameter;
        y = this.getHeight() / circleDiameter;

        paintComponent(this.getGraphics());
    }

}

So basicly i first calculate how many i can put on a row(x). Then i calculate how many rows are available(y). Then just keep drawing circles untill the amount of circles i drawed equals 'number' or untill it is filled, and the maximum number of rows is reached (y)

[SterAllures]

Oxano I wanted to thank you this works perfectly!!!!!!!!!!

Now I'm going to study the cody to actually understand what you did there .

If I have any question about it could I still ask them?

Really +rep for this and for all the trouble you did for me ;p.

Thanks!!!

[wim DC]

Yea sure. Ask ahead

[SterAllures]

Well as you know the code worked and I had some time to look it over but I had one question.

This method:
public void drawCircles(int n)

it says int n.

is that a pointer to somenthing? I don't really get twhat it is used for.

[wim DC]

n is the amount of circles that the user gave in.

In the actionperformed of the button:

mp.drawCircles(Integer.parseInt(tf.getText()));

[SterAllures]

So the variable n let's say it's 5 goes into number so variable number changes into 5

and the variable number is used here

 for (int regel = 0, total = 0; regel < y + 1 && total < number; regel++) {
            for (int hori = 0; hori < x && total < number; hori++) { 

so the variable number in the code above is the number you got from the input?


(Hope you understand it ;p)

[wim DC]

That is correct.
So after the program has drawed 5 circles it goes out of the 2 for loops. Otherwise it would continue drawing.