Key Listener Calculator Example in Java coding

Key Listener Calculator Example in Java coding

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/**
* @(#)KeyListenerCalculater.java
*
*
* @Satya_Rahul_Raj
* @https://www.facebook.com/groups/java.satya/
* @version 1.00 2012/9/28
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class Calculater
{
private Double num1,num2,sum,sub,mult,divi;

void accept(double num1,double num2)
{
this.num1=num1;
this.num2=num2;
sum=sub=mult=divi=0.0;
}
double add()
{
return(sum=num1+num2);

}
double minu()
{
return(sub=num1-num2);

}
double multi()
{
return(mult=num1*num2);

}
double divid()
{
return(divi=num1/num2);
}

}
public class KeyListenerCalculater extends JFrame implements KeyListener,FocusListener
{
private JLabel lbl1,lbl2,lbl3,lbl4,lbl5,lbl6;
private JTextField txt1,txt2,txt3;


public KeyListenerCalculater(String s)
{
super (s);
Container c=this.getContentPane();
c.setLayout(null);
lbl1=new JLabel("Enter First Number:");
lbl2=new JLabel("Enter Second Number:");
lbl3=new JLabel("Result:");
lbl4=new JLabel("F1=SUM, F2=SUBTARACT, F3=MULTIPLCATION");
lbl5=new JLabel("F4=DIVISION, ESC=EXIT, DELETE=TO CLAER BOX");
lbl6=new JLabel("https://www.facebook.com/groups/java.satya/");
txt1=new JTextField();
txt2=new JTextField();
txt3=new JTextField();

lbl1.setBounds(10,10,150,30);
lbl2.setBounds(10,50,150,30);
lbl3.setBounds(10,90,150,30);
lbl4.setBounds(10,150,300,30);
lbl5.setBounds(10,190,300,30);
lbl6.setBounds(10,230,300,30);
txt1.setBounds(180,10,100,30);
txt2.setBounds(180,50,100,30);
txt3.setBounds(180,90,100,30);

lbl1.setVisible(true);
lbl2.setVisible(true);
lbl3.setVisible(true);
lbl4.setVisible(true);
lbl5.setVisible(true);
lbl6.setVisible(true);
txt1.setVisible(true);
txt2.setVisible(true);
txt3.setVisible(true);
txt3.setEditable(false);

txt1.addKeyListener(this);
txt2.addKeyListener(this);
txt3.addKeyListener(this);
txt1.addFocusListener(this);
txt2.addFocusListener(this);
txt3.addFocusListener(this);


c.add(lbl1);
c.add(lbl2);
c.add(lbl3);
c.add(lbl4);
c.add(lbl5);
c.add(lbl6);
c.add(txt1);
c.add(txt2);
c.add(txt3);
}

public void keyTyped(KeyEvent ke)
{
}
public void keyPressed(KeyEvent ke)
{

if(ke.getKeyCode()==ke.VK_F1)
{
double a,b;
a=Double.parseDouble(txt1.getText());
b=Double.parseDouble(txt2.getText());
Calculater c=new Calculater();
c.accept(a,b);
txt3.setText(String.valueOf(c.add()));
}
if(ke.getKeyCode()==ke.VK_F2)
{
double a,b;
a=Double.parseDouble(txt1.getText());
b=Double.parseDouble(txt2.getText());
Calculater c=new Calculater();
c.accept(a,b);
txt3.setText(String.valueOf(c.minu()));
}
if(ke.getKeyCode()==ke.VK_F3)
{
double a,b;
a=Double.parseDouble(txt1.getText());
b=Double.parseDouble(txt2.getText());
Calculater c=new Calculater();
c.accept(a,b);
txt3.setText(String.valueOf(c.multi()));
}
if(ke.getKeyCode()==ke.VK_F4)
{
double a,b;
a=Double.parseDouble(txt1.getText());
b=Double.parseDouble(txt2.getText());
Calculater c=new Calculater();
c.accept(a,b);
txt3.setText(String.valueOf(c.divid()));
}
if(ke.getKeyCode()==ke.VK_ESCAPE)
{
System.exit(0);
}
if(ke.getKeyCode()==ke.VK_DELETE)
{
txt1.setText("");
txt2.setText("");
txt3.setText("");
}

}
public void focusGained(FocusEvent fe)
{
if(fe.getSource()==txt1)
{
txt1.setBackground(Color.ORANGE);
txt2.setBackground(Color.PINK);
}
if(fe.getSource()==txt2)
{
txt2.setBackground(Color.ORANGE);
txt1.setBackground(Color.PINK);
}
}
public void focusLost(FocusEvent fe)
{
if(fe.getSource()==txt1)
{

}
if(fe.getSource()==txt2)
{

}
}
public void keyReleased(KeyEvent ke)
{
}
}

class callKeyListenerCalculater
{

public static void main(String args[])
{
KeyListenerCalculater a=new KeyListenerCalculater("Key Listener Calculater BY [Rahul Raj]");
a.setBounds(400,400,350,300);
a.setVisible(true);
a.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}