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JApplet Problem - please help

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Maria

Posts: 2
Nickname: laurare
Registered: Dec, 2003

JApplet Problem - please help

Posted: Dec 7, 2003 7:23 AM

Hi everybody,

I'm trying to make this calculator program work as an applet and as an application. I tried using:


public class calcg extends JApplet implements ActionListener{

in many different ways, but it didn't work. Can sombody help me make it work?

Below is the source code for my calculator program.

Thanks in advance,

-Maria

ps-You can also e-mail me at laurare@rocketmail.com


// calculator 
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

public class calcg extends JFrame implements ActionListener
{
  private JButton one, two, three, four, five, six, seven, 
eight, nine, zero, dec, eq, plus, minus, mult, div, clear;
  private JLabel output, spacer;
  private Container container;
  private String operation;
  private double num1, num2, answer;
  private boolean clear_flag = false;
  
  //set up GUI
  public calcg()
  {
    //Create Title
    super("Calculator");
    JPanel container = new JPanel();	
    container.setLayout( new FlowLayout( FlowLayout.CENTER 
) );
    
    output = new JLabel("");	
    output.setBorder(new MatteBorder(2,2,2,2,Color.gray));
    output.setPreferredSize(new Dimension(1,26));	
    getContentPane().setBackground(Color.white);	
    getContentPane().add( "North",output );	
    getContentPane().add( "Center",container );
    
    //set up spacer
    spacer = new JLabel( "                                         
" );
    container.add( spacer );
    
    //set up clear
    clear = new JButton( "CE" );
    clear.addActionListener(this);
    container.add( clear );
    
    //set up seven and register its event handler
    seven = new JButton( "7" );
    seven.addActionListener(this);
    container.add( seven );

    
    //set up eight
    eight = new JButton( "8" );
    eight.addActionListener(this);
    container.add( eight );
    
    //set up nine
    nine = new JButton( "9" );
    nine.addActionListener(this);
    container.add( nine );
    
    //set up div
    div = new JButton( "/" );
    div.addActionListener(this);
    container.add( div );
    
    //set up four
    four = new JButton( "4" );
    four.addActionListener(this);
    container.add( four );
    
    //set up five
    five = new JButton( "5" );
    five.addActionListener(this);
    container.add( five );
    
    //set up six
    six = new JButton( "6" );
    six.addActionListener(this);
    container.add( six );
    
    //set up mult
    mult = new JButton( "*" );
    mult.addActionListener(this);
    container.add( mult );
    
    //set up one
    one = new JButton( "1" );
    one.addActionListener(this);
    container.add( one );
    
    //set up two
    two = new JButton( "2" );
    two.addActionListener(this);
    container.add( two );
    
    //set up three
    three = new JButton( "3" );
    three.addActionListener(this);
    container.add( three );
    
    //set up minus
    minus = new JButton( "-" );
    minus.addActionListener(this);
    container.add( minus );
    
    //set up zero
    zero = new JButton( "0" );
    zero.addActionListener(this);
    container.add( zero );
    
    //set up dec
    dec = new JButton( "." );
    dec.addActionListener(this);
    container.add( dec );
    
    //set up eq
    eq = new JButton( "=" );
    eq.addActionListener(this);
    container.add( eq );
    
    //set up plus
    plus = new JButton( "+" );
    plus.addActionListener(this);
    container.add( plus ); 
    
    //Set size and make visible
    setSize( 190, 225 );
    setVisible( true );
    setResizable( false );
  }
  
  public void actionPerformed(ActionEvent ae)
  {	
    JButton but = ( JButton )ae.getSource();	

    //Handle what button was pushed
    //Action for dec button
    if( but.getText() == "." )
    {
      //if dec is pressed, first check to make shure there 
is not already a decimal 
      String temp = output.getText();
      if( temp.indexOf( '.' ) == -1 )
        output.setText( output.getText() + but.getText() );
    }
    
    //Action for clear button
    else if( but.getText() == "CE" )
    {
      output.setText( "" );
      operation = "";
      num1 = 0.0;
      num2 = 0.0;
    }
    
    //Action for plus button
    else if( but.getText() == "+" )
    {
      operation = "+";
      num1 = Double.parseDouble( output.getText() );
      clear_flag = true;
      //output.setText( "" );
    }
    
    //Action for minus button
    else if( but.getText() == "-" )
    {
      operation = "-";
      num1 = Double.parseDouble( output.getText() );
      clear_flag = true;
      //output.setText( "" );
    }
    
    //Action for mult button
    else if( but.getText() == "*" )
    {
      operation = "*";
      num1 = Double.parseDouble( output.getText() );
      clear_flag = true;
      //output.setText( "" );
    }
    
    //Action for div button
    else if( but.getText() == "/" )
    {
      operation = "/";
      num1 = Double.parseDouble( output.getText() );
      clear_flag = true;
      //output.setText( "" );
    }
    
    //Action for eq button
    else if( but.getText() == "=" )
    {
      num2 = Double.parseDouble( output.getText() );
      //handle addition
      if( operation == "+" )
        answer = num1 + num2;
      else if( operation == "-" )
        answer = num1 - num2;
      else if( operation == "*" )
        answer = num1 * num2;
      else if( operation == "/" )
        answer = num1 / num2;        
      
      //display answer in output field
      output.setText( String.valueOf( answer ) ); 
      
      clear_flag = true;
      operation = "";
    }
    
    //Default action should only be used for numbers
    else
    {
      if( clear_flag == true )
      {
        output.setText( "" );
        clear_flag = false;
      }
      output.setText( output.getText() + but.getText() );
    }
  }
  
  //execute application
  public static void main( String args[] )
  {
    calcg application = new calcg();
    
    application.setDefaultCloseOperation( 
JFrame.EXIT_ON_CLOSE );
  }
}

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