Comments made by Linus Torvalds in his recent interview at Aalto Center for Entrepreneurship.

Just writing some interesting comments made by Linus Torvalds in this video that seemed to be both useful, humorous as well as weird.

1.Programming was not his hobby, its his HABIT.
2.He wrote his own assembler,editor and other tools.
3.But, he is not programming anymore.He does more of code mergings and maintainence.
4.Back in early Linux days,he doesnt know the difference between assembly and machine language.Unaware of that, he used to code in machine language (thats crazy).
5.He never ever did web programming simply because its not his interest.(Surprising that nowadays there are lots of web programmers).
6.He usually thinks like a computer.(Interesting..)
7.He is very annoyed of the tiny share of Linux in global desktop market space and his reason is that linux is not preinstalled on PC like Windows.but linux performs well in mobile platform( Android is a good example of this).
8.He doesnt care about business part of Linux or any decisions involved in it.Just programming.
9.He shows interest on open-source games.
10.He always wanted to be outrageous and doesnt mind if it offends someone.

Now for the crazy part,
1.One of the code contributor committed suicide because linus didnt accept his code.(so sad)
2.His words on Microsoft Windows 8 mobile:”… they are lying,they are full of sh*t” (Crowd applauds..lol)
3.And for Nvidia for its lack of linux support:”… Nvidia has been the single worst company we ever dealth with.So, Nvidia *(some abusive gestures) you” . I hope nvidia see this.

A very genius guy but with a rough attitude…
Have a nice day..

JFighter-A 2d Fighting Java Game.

This is a 2d fighting game that i made entirely using Java 6.Still incomplete.

Download it from the link below,

https://github.com/downloads/indiedev/JFighter/JFighter_2.7z

Controls:

X – Kick, Shift- change direction, Arrow Keys(as usual,movements)…..

Note: If the jar file is not opening on double-click, choose “Open with” and select “Java Platform(something similar)”.

Critics welcomed..

Bouncing ball with collision detection in Java

This program shows the same ball simulation with collision detection using “Rectangle” class of java.
Eg:-It works like this,
“r1.intersects(Rectangle r2)” method checks whether the r1 touches the r2.I have made special conditions for ball deflection based on the side it collides.

Class 1:Base Frame with some UI components

package ball_bounds;
import javax.swing.*;

import ball_bounds.canvas.ball;
import java.awt.*;
import java.awt.event.*;
public class base_frame extends JFrame implements ActionListener
{

	canvas draw_panel;
	JButton b_changebg,b_add,b_remove;
	JPanel ui_panel;
	base_frame()
	{
		super("Ball Bounds");

		//our UI panel which contains gui comps
		ui_panel=new JPanel();
		b_changebg=new JButton("Change Background");
		b_add=new JButton("Add");
		b_remove=new JButton("Remove");

		//add listeners
		b_changebg.addActionListener(this);
		b_add.addActionListener(this);
		b_remove.addActionListener(this);

		setLayout(new FlowLayout());
		draw_panel=new canvas();

		//adding to UI panel
		ui_panel.add(b_changebg);
		ui_panel.add(b_add);
		ui_panel.add(b_remove);

		//adding to our JFrame
		add(draw_panel);
		add(ui_panel);

		setSize(540,470);
		setVisible(true);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

	public static void main(String[] args)
	{
		new base_frame();
	}
	public void actionPerformed(ActionEvent ae)
	{
		if(ae.getSource()==b_changebg)
		{
				draw_panel.changeBGcolor();
		}
		else
		if(ae.getSource()==b_add)
		{
			//adds a ball of size 20;
			draw_panel.addBall(20);
			System.out.println("Added a ball");
		}
		else
		if(ae.getSource()==b_remove)
		{
				draw_panel.removeBall();
				System.out.println("Removed a ball");
		}
	}
}

Class 2:Our Drawing canvas

package ball_bounds;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class canvas extends JComponent implements KeyListener,MouseMotionListener
{
	//display details
	private final int width=512;
	private final int height=384;
	boolean bg_change=false;
	int color=254,incr=1;

	//a  ball array
	ArrayList ballarray;

	//my custom box
	My_box b1;

	canvas()
	{
		ballarray=new ArrayList(1);
		b1=new My_box(0,0,120,20);

		addKeyListener(this);
		addMouseMotionListener(this);

		setPreferredSize(new Dimension(width,height));
		setFocusable(true);
	}

	//change to background color dynamically(default:white)
	public void changeBGcolor()
	{
		if(bg_change)
		{
			bg_change=false;
		}
		else
		{
			bg_change=true;
		}
	}

	//add a new ball by passing a "ball" class instance
	public void addBall(int size)
	{
		//added to the arraylist
		ballarray.add(new ball(size));
	}

	public void removeBall()
	{
		if(!ballarray.isEmpty())
		{
			ballarray.remove(ballarray.size()-1);
		}
	}
	public int getBallCount()
	{
			return ballarray.size();
	}
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);

		//fill rect
		if(bg_change)
		{
			color=color-incr;

			 if(color<1)                         
                        {
                                    incr=-1;                         
                        }             
                         if(color>250)
			{
				incr=1;
			}
			g.setColor(new Color(color,color,color));
		}
		else
		{
			color=254;
			g.setColor(Color.WHITE);
		}
		g.fillRect(0,0,getWidth(),getHeight());

		//my box
		g.setColor(Color.BLACK);
		b1.drawBox(g);

		try{
			Thread.sleep(5);
			for(ball temp_ball:ballarray)
			{
				//drawing the ball using "drawBall(Graphics g,boolean)".
				//boolean is for displaying ball's bounding rectangle which deals with collision
				temp_ball.drawBall(g,false);

				//checking for collision with our movable pad
				temp_ball.collision(b1);
			}
			repaint();//calls the paint method

		}catch(Exception e)
		{
			System.out.println(e);
		}
	}

	//keyboard call-back methods
	public void keyPressed(KeyEvent ke)
	{
		if(ke.getKeyCode()==KeyEvent.VK_RIGHT)//increase x
		{

			b1.translate(10,0);
		}
		else
		if(ke.getKeyCode()==KeyEvent.VK_LEFT)
		{
			b1.translate(-10,0);
		}
       	}
	public void keyReleased(KeyEvent ke)
	{
	}
	public void keyTyped(KeyEvent ke)
	{

	}

	//mouse call-back methods

	public void mouseMoved(MouseEvent me)
	{
		//move the rectangle box too
		b1.setLocation(me.getX(),me.getY());
	}
	public void mouseDragged(MouseEvent me)
	{

	}

	//Ball inner-class
	class ball
	{
		private int x_pos=0;
		private int y_pos=0;
		private int dir_x=1;
		private int dir_y=1;
		private int size=0;

		ball(int size)
		{
			this.size=size;
		}

		private void calculate_direction()
		{
			//move the ball
			x_pos=x_pos-dir_x;
			y_pos=y_pos-dir_y;

			//for X-direction
			if(x_pos<0)
                        { 		       
                            x_pos=0; 	
          		    dir_x=-1;//incr   
                        }
                        else   
                       if(x_pos+size>getWidth())
			{
				 dir_x=1;//decr
			}

			//for Y-direction
			if(y_pos<0)  
                        {  
                                 y_pos=0;     
                             dir_y=-1;//incr                         

                        }                         
                         else                                            
                         if(y_pos+size>getHeight())
			{
				dir_y=1;//decr
			}
		}

		public void changeDirection_Y()
		{
             		if(dir_y==-1)
			{
				dir_y=1;
			}
			else
			{
				dir_y=-1;
			}
		}

		public void changeDirection_X()
		{
			if(dir_x==-1)
			{
				dir_x=1;
			}
			else
			{
				dir_x=-1;
			}
		}

		public void drawBall(Graphics g,boolean bound)
		{
			calculate_direction();
			g.setColor(Color.BLUE);
			g.fillOval(x_pos,y_pos,size,size);

			if(bound)
			{
				g.drawRect(x_pos,y_pos,size,size);
			}
		}

		public Rectangle getRectBounds()
		{
			return new Rectangle(x_pos,y_pos,size,size);
		}

                //this method is called for all balls and checked whether it touches the rect.if so,the ball's direction gets changed accordingly.
		public void collision(My_box rect)
		{
                           //if ball collides with top/bottom part of the rect
			if(this.getRectBounds().intersectsLine(rect.x,rect.y,rect.x+rect.width,rect.y) ||
                           this.getRectBounds().intersectsLine(rect.x,rect.y+rect.height, rect.x+rect.width,rect.y+rect.height))
			{

				changeDirection_Y();//reverses the direction along Y

			}

			  //if ball collides with left/right part of the rect
			if(this.getRectBounds().intersectsLine(rect.x,rect.y    ,    rect.x,rect.y+rect.height) ||
                           this.getRectBounds().intersectsLine(rect.x+rect.width,rect.y  ,   rect.x+rect.width,rect.y+rect.height))
			{
				changeDirection_X();//reverses the direction along X

			}

		}
	}
}

Class 3:Our “My_box ” class.
This class extends Rectangle class.It is written in separate class just for future scalability.nothing specific

package ball_bounds;
import java.awt.*;
import java.awt.event.*;
class My_box extends Rectangle
{
	//default vars
	/*
	 * x,y,width,height
	 */
	My_box(int x1,int y,int width,int height)
	{
		super(x1,y,width,height);
	}

	public void drawBox(Graphics g)
	{
		g.setColor(Color.BLACK);
		g.fillRect(x,y,width,height);
	}
}

This is the Screenshot

Screenshot:

Run and see the output: Download

Bouncing balls in Java Swing

This program displays several ball(more precisely “circles”) bouncing off the sides of the enclosing component.

Code 1:The JFrame class (Main window)

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class base_frame extends JFrame
{
	
	Container c;
	
	//our components
	JPanel b_panel;
	JButton b_add,b_sub;
	JLabel l_counter,l_ballsize;
	JTextField t_ballsize;
	
	//Actionlistener class instance
	handler handle;
	
	//class which contains drawing surface "JComponent"
	canvas ballcanvas;
	
	base_frame()
	{
		super("Ball Simulator");
		c=getContentPane();
		
		//setting to "flowlayout"
		c.setLayout(new FlowLayout());
		
		//all components
		t_ballsize=new JTextField(2);
		l_counter=new JLabel("Ball Count:  ");
		l_ballsize=new JLabel("Ball Size:  ");
		l_counter.setBorder(BorderFactory.createBevelBorder(1));
		b_add=new JButton("Add");
		b_sub=new JButton("Remove");
		handle=new handler();
		//adding actionlistener to buttons
		b_add.addActionListener(handle);
		b_sub.addActionListener(handle);
		
		//button panel 
		b_panel=new JPanel();//panel to hold buttons,textfields..
		b_panel.add(l_ballsize);//label
		b_panel.add(t_ballsize);//textfield to input ball size
		b_panel.add(b_add);//button to add a ball
		b_panel.add(b_sub);//button to del a ball (the most recent one)
		b_panel.add(l_counter);//label displaying total balls being rendered
		
		//ball canvas
		ballcanvas=new canvas(); 
		
		//container details
		c.add(ballcanvas);//adding drawing surface(ballcanvas) to main jframe
		c.add(b_panel);//adding the panel along with its smaller components
		
		//set visuals
		setSize(640,480);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	
	}
	public static void main(String[] args)
	{
		new base_frame();//creating main jframe instance
	}
	
	//an inner class to take care of button events
	class handler implements ActionListener
	{
		public void actionPerformed(ActionEvent ae)
		{
			//if "Add" button clicked
			if(ae.getSource()==b_add)
			{
				if(!t_ballsize.getText().equals(""))
				{
					
					try{
						ballcanvas.addBall(Integer.parseInt(t_ballsize.getText()));
						
						//updates the counter label
						l_counter.setText("Ball Count:"+ballcanvas.countBall());
					}catch(NumberFormatException e)
					{
						System.out.println(e);
						JOptionPane.showMessageDialog(null,"Enter only numbers!","Invalid Input",JOptionPane.INFORMATION_MESSAGE);
						
					}
					
				}
				else
				{
					JOptionPane.showMessageDialog(null,"Enter the ball size!","Input needed",JOptionPane.INFORMATION_MESSAGE);
				}
			}//b_add
			
			//if "Sub" button clicked
			if(ae.getSource()==b_sub)
			{
				ballcanvas.removeBall();
				//updates the counter label
				l_counter.setText("Ball Count:"+ballcanvas.countBall());
			}
		}
	}
}

Code 2:The drawing surface class .JComponent used

import java.awt.*;
import javax.swing.*;
import java.util.*;
public class canvas extends JComponent
{
	//display details	
	private final int width=512;
	private final int height=384;
	
	//ball array
	final private ArrayList<ball> ball_array;
	
	canvas()
	{
		ball_array=new ArrayList<ball>();
		
		setPreferredSize(new Dimension(width,height));
		setBorder(BorderFactory.createEtchedBorder(1));
	}
	
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		g.setColor(Color.BLACK);
		
		//fill rect
		g.fillRect(0,0,getWidth(),getHeight());
		try
		{
			//draw balls from ball_array
			for(int i=0;i<ball_array.size();i++)
			{
				ball_array.get(i).drawBall(g);
				//System.out.println("Drawing ball");
			}
			Thread.sleep(5);//to control animation speed

		}catch(InterruptedException e)
		{
			System.out.println("cannot control the paint thread!!");
		}
		repaint();//calls the paint method 
	}
	
	//to add a ball
	public void addBall(int size)
	{
		ball_array.add(new ball(size));
	}
	
	//to remove a ball
	public void removeBall()
	{
		if(!ball_array.isEmpty())
		{
			ball_array.remove(ball_array.size()-1);
		}
		
	}
	
	//return total balls from the array
	public int countBall()
	{
		return ball_array.size();
	}
	
	//Ball inner-class
	class ball
	{
		private int x_pos=0;
		private int y_pos=0;
		private int dir_x=1;
		private int dir_y=1;
		private int size;
		
		ball(int size)
		{
			this.size=size;
		}
		
		private void calculate_direction()
		{
			//move the ball
			x_pos=x_pos-dir_x;
			y_pos=y_pos-dir_y;
			
			//for X-direction
			if(x_pos<0)
			{
				x_pos=0;
				dir_x=-1;//incr
			}
			else
			if(x_pos+size>getWidth())
			{
				dir_x=1;//decr
			}
			
			//for Y-direction
			if(y_pos<0)
			{
				y_pos=0;
				dir_y=-1;//incr
			}else
			if(y_pos+size>getHeight())
			{
				dir_y=1;//decr
			}
		}
		
		public void drawBall(Graphics g)
		{
			calculate_direction();
			g.setColor(Color.WHITE);
			g.drawOval(x_pos,y_pos,size,size);
		}
	}
}

Download the jar file : Ball Simulate

GUI application in Python using wxPython

This is a simple login application created using wxPython in python.Only the front-end is shown here.The backend working is in another tutorial.

Note:Make sure that you know the Classes  and inheritance concepts of python before reading this.See this tutorial for short intro of the same http://praveenmax.wordpress.com/2011/02/17/creating-class-in-python/

The Source:

import wx; #importing wxpython packages
class myframe(wx.Frame):#Inheriting the "wx.Frame" class into our myframe class
    #our constructor
    def __init__(self,parent,title):
        #calling the constructor of wx.Frame
        wx.Frame.__init__(self,parent,-1,title);
        #Our panel
        basepanel=wx.Panel(self,-1);

        #some custom fonts
        #syntax:wx.Font(size,font_family,font_style,font_weight)
        font1 = wx.Font(12, wx.DEFAULT, wx.FONTSTYLE_NORMAL, wx.LIGHT);
        font = wx.Font(15, wx.DEFAULT, wx.FONTSTYLE_NORMAL, wx.BOLD)

        #this is the BoxSizer
        #syntax:wx.BoxSizer(orientation)
        basebox=wx.BoxSizer(wx.VERTICAL);

        #This is our name field
        ip_box=wx.BoxSizer(wx.HORIZONTAL);#A boxresizer
        ip_label=wx.StaticText(basepanel,label="User name");#Label "Username"
        ip_label.SetFont(font1)#setting custom font to label
        ip_text=wx.TextCtrl(basepanel,-1,"enter text here");#TextField for Username

        #adding Username label & its textfield to ip_box BoxSizer
        #syntax:Add(parent,id,proportion,spacing)
        ip_box.Add(ip_label,-1,wx.ALL,5);#wx.ALL means spacing of 5px in "all direction"
        ip_box.Add(ip_text,-1,wx.ALL,5);

        #password field
        pwd_box=wx.BoxSizer(wx.HORIZONTAL);
        pwd_label=wx.StaticText(basepanel,label="Password");
        pwd_label.SetFont(font1);
        pwd_text=wx.TextCtrl(basepanel,-1);

        pwd_box.Add(pwd_label,-1,wx.ALL,5);
        pwd_box.Add(pwd_text,-1,wx.ALL,5);

        #WELCOME title
        title_box=wx.BoxSizer(wx.HORIZONTAL);
        title_text=wx.StaticText(basepanel,label="Login Frame");#a non-editable text
        title_text.SetFont(font);
        title_box.Add(title_text,-1);

        #OK button
        bt_box=wx.BoxSizer(wx.HORIZONTAL);
        ok_bt=wx.Button(basepanel,-1,"Login");
        cancel_bt=wx.Button(basepanel,-1,"Cancel");
        bt_box.Add(ok_bt,-1,wx.ALL,5);
        bt_box.Add(cancel_bt,-1,wx.ALL,5);

        #adding everything to basebox
        basebox.Add(title_box,0,wx.CENTER,10);
        basebox.Add(wx.StaticLine(basepanel),0,wx.ALL|wx.EXPAND,5);
        basebox.Add(ip_box,0,wx.CENTER,10);
        basebox.Add(pwd_box,0,wx.CENTER,10);
        basebox.Add(bt_box,0,wx.CENTER,10);

        #adding basebox to basepanel
        basepanel.SetSizer(basebox);
        #automatically setting up the frame size
        basebox.Fit(self);

myapp=wx.App();
tempframe=myframe(None,"MyFrame");#our frame instance
tempframe.Show(True);#making frame visible
myapp.MainLoop();

Login Frame using wxPython

The comments in the corresponding lines will explain most of the meanings except the “wx.BoxSizer()” stuff.The image below explains it

BoxSizers revealed

BoxSizer is a layout manager which is used to arrange widgets either vertically or horizontally.It holds the widgets together.
In the image,there are 5 BoxSizer.The blue box shows the main BoxSizer of our Frame and it also contains 4 more BoxSizer.Refer to the colors.

 #WELCOME title
        title_box=wx.BoxSizer(wx.HORIZONTAL);
        title_text=wx.StaticText(basepanel,label="Login Frame");#a non-editable text
        title_text.SetFont(font);
        title_box.Add(title_text,-1);

The above code is the First BoxSizer.This contains a static text “Frame Login” .Similarly,…..

        ip_box=wx.BoxSizer(wx.HORIZONTAL);#A boxresizer 
        ip_label=wx.StaticText(basepanel,label="User name");#Label "Username"
        ip_label.SetFont(font1)#setting custom font to label
        ip_text=wx.TextCtrl(basepanel,-1,"enter text here");#TextField for Username 
        
        #adding Username label & its textfield to ip_box BoxSizer
        #syntax:Add(parent,id,proportion,spacing)
        ip_box.Add(ip_label,-1,wx.ALL,5);#wx.ALL means spacing of 5px in "all direction"
        ip_box.Add(ip_text,-1,wx.ALL,5);

The second BoxSizer contains the “Username” label  and a Textfield.

    #password field
        pwd_box=wx.BoxSizer(wx.HORIZONTAL);
        pwd_label=wx.StaticText(basepanel,label="Password");
        pwd_label.SetFont(font1);
        pwd_text=wx.TextCtrl(basepanel,-1);
        
        pwd_box.Add(pwd_label,-1,wx.ALL,5);
        pwd_box.Add(pwd_text,-1,wx.ALL,5);

The third BoxSizer contains the “Password” label and a Textfield.

 # button
        bt_box=wx.BoxSizer(wx.HORIZONTAL);
        ok_bt=wx.Button(basepanel,-1,"Login");
        cancel_bt=wx.Button(basepanel,-1,"Cancel");
        bt_box.Add(ok_bt,-1,wx.ALL,5);
        bt_box.Add(cancel_bt,-1,wx.ALL,5);

The fourth BoxSizer contains the “Login” and “Cancel” button.

All these 4 BoxSizers are enclosed by another BoxSizer which is then added to wx.Panel(refer Line 60).

Done!

Creating Class in Python

class Employee:
    #these are the instance variables
    sal=0;
    name="none";

    #This is a function definition.
        #the keyword "self" is MUST!It is similar to "this" in java.It says that this method belongs to Employee class.(explicitly saying)
    #"__init__() is the constructor in python.

    def __init__(self,name,sal):
        self.name=name;
        self.sal=sal;
        print "instance created";

    #a normal method
    def display(self):
        print "*"*20;
        print "Name:",self.name;
        print "Salary:",self.sal;
        print "*"*20;

#class ends

#creating class instance and storing in variable "temp_var"
temp_var=Employee("max",10000);
#display the values
temp_var.display();

Output:

instance created
********************
Name: max
Salary: 10000
********************

XML parsing in Java

XML parsing is used to read data from an XML file.

Before parsing ,the xml schema file is needed.It defines the structure and the valid tags for the xml file.

Our XML-Schema file:

<? xml version="1.0"?>
<xs:schema  xmlns:xsd="http://www.w3.org/2001/XMLSchema" >
	<xs:element name="employee">
		<xs:complexType>
			<xs:sequence>
			<xs:element name="name">
				<xs:complexType>
					<xs:element name="firstname" type="xs:string" />
					<xs:element name="lastname"  type="xs:string" />
				</xs:complexType>
			<xs:element name="age" type="xs:integer" />
			</xs:element>
			</xs:sequence>
		</xs:complexType>
	</xs:element>
</xs:schema>

The xmlns:xsd refers to the xml schema which contains the datatypes and other default tags that can be used.

Our XML-data file:

This is a simple XML file that contains the data enclosed in the tags.The tags used in this file must conform with the Schema file above.Elese it wont parse well.

 

<?xml version="1.0" encoding="ISO-8859-1"?>
<company xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"	xsi:noNamespaceSchemaLocation="schema.xsd">

	<employee>
		<name>
			<firstname>User</firstname>
			<lastname>one</lastname>
		</name>
		<age>10</age>
	</employee>

	<employee>
		<name>
			 <firstname>User</firstname>
			 <lastname>two</lastname>
		</name>
		<age>6</age>
	</employee>

</company>

Now open our XML data file in a browser which supports XML parsing(Google Chrome).

Painting a Circle using TouchListener in Android

This program is used to create a colored circle using a View context whenever the user touch the screen.The color generated is random and changes rapidly when dragged…

Note:A basic knowledge in Android needed .

Project structure:-

Source 1:

This is the Activity class.We simply create an instance of our “drawingView” class(which extends View) and add it to current content view…

package com.android;

import android.app.Activity;
import android.os.Bundle;

public class Activity1 extends Activity{
    /** Called when the activity is first created. */

    drawingView dview;                    //creating the reference

    public void onCreate(Bundle savedInstanceState)
   {
        super.onCreate(savedInstanceState);
        dview=new drawingView(this); //creating the instance
        setContentView(dview);         //adding to the activity
    }
}

Source 2:

This is our “drawingView” class which extends the “View” class from “import android.view.View” package.  This class contains the following logic,

• Generating a random color value .
• Implements “OnTouchListener” for generating touch events.
• Drawing the circle.

package com.android;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
public class drawingView extends View implements OnTouchListener{

	static int x,y,r=255,g=255,b=255;
	final static int radius=30;
	Paint paint;     //using this ,we can draw on canvas

	public drawingView(Context context)
	{
		super(context);
	        paint=new Paint();
		paint.setAntiAlias(true);       //for smooth rendering
		paint.setARGB(255, r, g, b);    //setting the paint color

		//to make it focusable so that it will receive touch events properly
		setFocusable(true);

		//adding touch listener to this view
		this.setOnTouchListener(this);
	}

	//overriding the View's onDraw(..) method
	public void onDraw(Canvas canvas)
	{
		paint.setARGB(255, r, g, b);

		//drawing the circle
		canvas.drawCircle(x,y,radius,paint);

	}

	//this is the interface method of "OnTouchListener"
	public boolean onTouch(View view,MotionEvent event)
	{
		x=(int)event.getX()-(radius/2);      //some math logic to plot the circle  in exact touch place
		y=(int)event.getY()-(radius/2);
		  //System.out.println("X,Y:"+"x"+","+y);      //see this output in "LogCat"
		randColor();       //calls this method to generate a color before drawing
		invalidate();      //calls onDraw method
		return true;
	}

	//this method sets a random color using Math.random()
	//Note: RGB color values ranges from 0 to 255..
	public void randColor()
	{
		r=(int)(Math.random()*255);
		g=(int)(Math.random()*255);
		b=(int)(Math.random()*255);
		//Toast.makeText(c, "r,g,b="+r+","+g+","+b,Toast.LENGTH_SHORT).show();
	}
}

Output:
Some screenshots in Emulator,

This slideshow requires JavaScript.

Note:The above slideshow(a wordpress plugin) has some bug and so it displays the file structure picture…ignore it

Creating Frame in wxPython

Code:

Note:Use “portable python” IDE since it has wxPython by default.

import wx                      //importing the core package of wxPython

class MyApp(wx.App):           //creating a class "MyApp" instantiating the "wx.App" 
 def OnInit(self):             //constructor for the class
     myframe=wx.Frame(parent=None,title="A sample Frame")  //creating a frame(parent,title)
     myframe.Show()             //set the frame to be visible
     return True               //true if the constructor runs without errors else return false implicitly
//-------------end of the class------------------
myapp=MyApp()                  //creating an instance of MyApp class
myapp.MainLoop()               //starting a loop for dispatching  events.

Output:

A simple frame

NOTE:Make sure you indent your python codes properly before running to prevent compilation errors!

Installing Python the easy way

Instead of downloading the Python from the official site,download the portable version of Python 2.6 which comes with several modules such wxPython(GUI programming ) , Iron Python(For C# ) ,pyGame …

 

Download Python IDE from this link

• Portable Python 1.1 based on Python 2.6.1(44 mb approx)

Do not download Python 3.0.1 at least for now.Python 2.6 is enough for most of the tasks.