I have a problem in java applet and I need Help ????

mema_UAE · 04-26-2006, 11:33 AM

Hi friends

I don’t know how to color the circle when I press the button

here is my code

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class circle extends Applet implements ActionListener
{

Button b1=new Button("Bule");
Button b2=new Button("Yellow");

public void init ()
{
add(b1);
b1.addActionListener(this);

add(b2);
b2.addActionListener(this);
}

public void paint (Graphics g)
{
g.drawOval(30, 50, 100, 100);

g.drawOval(135, 50, 100, 100);
}

public void actionPerformed(ActionEvent e)
{
if (e.getSource()==b1)
{
repaint();
}

if (e.getSource()==b2)
{
repaint();
}
}

}

deroB · 04-26-2006, 11:56 AM

Looks like homework to me

check out the java docs on Graphics and Color.
http://java.sun.com/j2se/1.5.0/docs/api/index.html

"g.setColor(java.awt.Color)" in the paint method is what you are looking for

mema_UAE · 04-26-2006, 12:43 PM

Thanks deroB for your quick reply , I know how to use the g.setColor in

public void paint (Graphics g)
{ g.setColor(Color.black);
g.drawOval(30, 50, 100, 100);
g.drawOval(135, 50, 100, 100);
}

the problem is I don’t know how to use the g.setColor(Color.green) in

public void actionPerformed(ActionEvent e) which I can change the color of circle to

blue if when I press the button(blue) .

Mega Man X · 04-26-2006, 01:01 PM

Here:

Code:

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class Circle extends Applet implements ActionListener {


    private Button blue = new Button("Blue");
    private Button red = new Button("Red");

    private Color color;

    public void init () {
        
        add(blue);
        blue.addActionListener(this);

        add(red);
        red.addActionListener(this);
    }



    public void paint (Graphics g) {

        g.setColor(color);
        
        g.drawOval(30, 50, 100, 100);

        g.drawOval(135, 50, 100, 100);
    }


    public void actionPerformed(ActionEvent e) {
        
        if (e.getSource()== blue) {
            color = Color.blue;
            repaint();
        }

        if (e.getSource()== red) {
            color = Color.red;
            repaint();
        }
    }
}

Few tips: You might consider naming Java classes with uppercases (thus Circle, not circle). Lowercases are usually used for variables name. You may also want to use the <code></code> tags when posting here. It gets easier to read ^_^.

Regards!

mema_UAE · 04-27-2006, 05:27 AM

Thanks ..... Mega Man X ..... for the correction ......

The problem is when I click the blue button the two circles color will change to blue, I just want to change one circle color to blue when I click the button blue and the other circle color will be red if I click the button red.

Mega Man X · 04-27-2006, 08:33 AM

No problems. I can't test the following code right now but I can tell you why it won't work

. If you press the red button once, it will work. If you press the blue button, it will work. Now, if you press either button twice, both circles will be of the same color.

I will let you puzzle a litte with the code and try to find a way to fix it ^_^. It's possible, but the very best solution in this case would be to create a Circle class with a paint method I believe. In this paint method you would have the color and position to draw the circle. You will then make a call for the Circle's paint method inside your paing (Graphics g) method. Anyway, good luck

Code:

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class Circle extends Applet implements ActionListener {


    private Button blue = new Button("Blue");
    private Button red = new Button("Red");

    private Color color;
    private Color old_color;

    public void init () {
        
        add(blue);
        blue.addActionListener(this);

        add(red);
        red.addActionListener(this);
    }



    public void paint (Graphics g) {

        g.setColor(color);
        
        g.drawOval(30, 50, 100, 100);
        
        g.setColor(old_color);

        g.drawOval(135, 50, 100, 100);
    }


    public void actionPerformed(ActionEvent e) {
        
        if (e.getSource()== blue) {
            old_color = color;
            color = Color.blue;
            repaint();
        }

        if (e.getSource()== red) {
            old_color = color;
            color = Color.red;
            repaint();
        }
    }
}

mema_UAE · 04-27-2006, 11:37 AM

Thanks ..... Mega Man X again ..... for your help......

The code is working know properly but it just has a simple problem which I try to
fix it but I couldn’t. In the beginning when I click the blue button the 2 circle color change to blue (that is the wrong) because I want just one circle color change to blue and the other color have to be black till I click the button red . Its right after when I click button red the circle 2 colors change to red and the circle 1 color still blue.

mema_UAE · 04-27-2006, 05:18 PM

I Need Help ?????