Banner Applet is an applet application which continuously rotates the text chars after given time interval.

For Example,

This is Demo.
his is Demo.T
is is Demo.Th
…

How to write program for this?

  1. We need applet first. Will follow the applet life cycle 
    import java.applet.*;
import java.awt.*;

public class bannerDemo extends Applet
{
	public void init()
	{
	}
	public void paint(Graphics g)
	{
	}		
}
/*
<applet code="bannerDemo" width="500" height="150"></applet>
*/
  2. We want to draw a String on applet area. Which can be done by calling drawString() method of Graphics class inside paint() method. 
    	public void paint(Graphics g)
	{
		Font f = new Font("Arial",Font.BOLD,36);
		g.setFont(f);
		g.drawString("Ankit Virparia (ankit.co)",50,75);
	}
  3. We want continuous change in the text which we have printed so, Will go for multithreading. 
    public class bannerDemo extends Applet implements Runnable
{
	Thread t;
        public void run()
	{}
}
  4. Here one extra thread will be given a responsibility to update the text given (which is stored in a global variable – I mean common between paint() and run() methods) 
    public class bannerDemo extends Applet implements Runnable
{
	Thread t;
	String msg = "Ankit Virparia (ankit.co)";
	
	public void run()
	{
		try
		{
			while(true)
			{
				t.sleep(1000);
				char c = msg.charAt(0);
				String tmp = msg.substring(1,msg.length());
				msg = tmp + c;
				repaint();
			}
		}
		catch(Exception e)
		{
			System.out.println(e);	
		}
	}
		
	public void paint(Graphics g)
	{
		Font f = new Font("Arial",Font.BOLD,36);
		g.setFont(f);
		g.drawString(msg,50,75);
	}	
	
}
  5. We need to start the thread in the beginning. Which can be written in init() method. 
    	Thread t;
	public void init()
	{
		t = new Thread(this);
		t.start();
	}
  6. paint() is invoked only when a user does GUI related change. But here in our case we want to invoke paint() at the interval of 1 second. 
    

    7. 

  7. We are ready to go!
    8. 





Program for Banner Applet


File Name:bannerDemo.java


import java.applet.*;
import java.awt.*;

public class bannerDemo extends Applet implements Runnable
{
	Thread t;
	String msg = "Ankit Virparia (ankit.co)";
	public void init()
	{
		t = new Thread(this);
		t.start();
	}
	
	public void run()
	{
		try
		{
			while(true)
			{
				t.sleep(1000);
				char c = msg.charAt(0);
				String tmp = msg.substring(1,msg.length());
				msg = tmp + c;
				repaint();
			}
		}
		catch(Exception e)
		{
			System.out.println(e);	
		}
	}
		
	public void paint(Graphics g)
	{
		Font f = new Font("Arial",Font.BOLD,36);
		g.setFont(f);
		g.drawString(msg,50,75);
	}	
	
}

/*
<applet code="bannerDemo" width="500" height="150"></applet>
*/



p5