how do I add Action Listener to my code to make the calculator work

**alex1994** · March 7th, 2014, 02:08 PM

here is the code i already have made;

import java.awt.*;
import javax.swing.*;

public class EX_7_2 extends JFrame
{
public EX_7_2()
{
setLayout(new BorderLayout(5, 10));

// create p1
JPanel p1 = new JPanel();
p1.setLayout(new BorderLayout(5, 10));

p1.add(new JTextField(), BorderLayout.NORTH);
JPanel p3 = new JPanel();
p3.setLayout(new GridLayout(1, 3, 5, 5));
JButton btBackspace = new JButton ("Backspace");
btBackspace.setBackground(Color.WHITE);
btBackspace.setForeground(Color.RED);

JButton btCE = new JButton ("CE");
btCE.setBackground(Color.WHITE);
btCE.setForeground(Color.RED);

JButton btC = new JButton ("C");
btC.setBackground(Color.WHITE);
btC.setForeground(Color.RED);

p3.add(btBackspace);
p3.add(btCE);
p3.add(btC);

p1.add(p3, BorderLayout.CENTER);

// create p4

JPanel p2 = new JPanel();
p2.setLayout(new GridLayout(4, 3, 5, 5));

int num;
for (int iRow = 3; iRow>0; iRow--)
{
for (int iCol = 1; iCol<4; iCol++)
{
num = 3*(iRow-1) + iCol;

JButton btBody = new JButton("" + num);
btBody.setBackground(Color.WHITE);
btBody.setForeground(Color.BLUE);
p2.add(btBody);
}
}

JButton btZero = new JButton ("0");
btZero.setBackground(Color.WHITE);
btZero.setForeground(Color.BLUE);

JButton btPlusMinus = new JButton ("+/-");
btPlusMinus.setBackground(Color.WHITE);
btPlusMinus.setForeground(Color.BLUE);

JButton btDot = new JButton (".");
btDot.setBackground(Color.WHITE);
btDot.setForeground(Color.BLUE);

p2.add(btZero);
p2.add(btPlusMinus);
p2.add(btDot);

JPanel p5 = new JPanel();
p5.setLayout(new GridLayout(4, 2, 5, 5));

JButton btBack = new JButton ("/");
btBack.setBackground(Color.WHITE);
btBack.setForeground(Color.RED);

JButton btsprt = new JButton ("sprt");
btsprt.setBackground(Color.WHITE);
btsprt.setForeground(Color.BLUE);

JButton btStar = new JButton ("*");
btStar.setBackground(Color.WHITE);
btStar.setForeground(Color.RED);

JButton btPercentage = new JButton ("%");
btPercentage.setBackground(Color.WHITE);
btPercentage.setForeground(Color.BLUE);

JButton btMinus = new JButton ("-");
btMinus.setBackground(Color.WHITE);
btMinus.setForeground(Color.RED);

JButton btOnex = new JButton ("1/x");
btOnex.setBackground(Color.WHITE);
btOnex.setForeground(Color.BLUE);

JButton btPlus = new JButton ("+");
btPlus.setBackground(Color.WHITE);
btPlus.setForeground(Color.RED);

JButton btEquals = new JButton ("=");
btEquals.setBackground(Color.WHITE);
btEquals.setForeground(Color.RED);

p5.add(btBack);
p5.add(btsprt);
p5.add(btStar);
p5.add(btPercentage);
p5.add(btMinus);
p5.add(btOnex);
p5.add(btPlus);
p5.add(btEquals);

JPanel p4 = new JPanel();
p4.setLayout(new BorderLayout(5, 10));
p4.add(p2, BorderLayout.CENTER);
p4.add(p5, BorderLayout.EAST);

add(p1, BorderLayout.NORTH );
add(p4, BorderLayout.CENTER);
}

public static void main(String[] args) {

EX_7_2 frame = new EX_7_2();
frame.setTitle("Calculator");
frame.setSize(350, 375);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOS E);
frame.setVisible(true);
}
}

**Norm** · March 7th, 2014, 02:32 PM

Please edit your post and wrap your code with code tags:
[code=java]
YOUR CODE HERE
[/code]
to get highlighting and preserve formatting.

See the tutorial: How to Write an Action Listener (The Java™ Tutorials > Creating a GUI With JFC/Swing > Writing Event Listeners)

**Harry Blargle** · March 7th, 2014, 02:32 PM

google "java actionlistener", it's the first result

**alex1994** · March 7th, 2014, 03:40 PM

I HAVE LOOKED AT THE TUTORIAL BUT I STILL DON'T UNDERSTAND

**Norm** · March 7th, 2014, 03:57 PM

There are several steps needed.
1) create a class that implements the ActionListener interface
2) create an instance of the above class
3) use the addActionListener() method to add that instance as the action listener for a component.

**GregBrannon** · March 7th, 2014, 03:58 PM

Post your code correctly. Give your variables better names. Don't shout. Describe exactly what you don't understand.

We can't do a Vulcan mind meld and infuse you with total Java consciousness. We need to know specifically what you need help with.

**alex1994** · March 7th, 2014, 04:53 PM

Hi, i know that i need ;

public void actionPerformed(ActionEvent e) {

}

how i don't know how to give each individual number in the calculator a action so that the number appear.

Sorry to Mr GregBrannon, i was typing without realizing i had caps lock on and sent the post without realizing.

**Norm** · March 7th, 2014, 05:05 PM

how to give each individual number in the calculator a action

There are a couple of approaches:
1)Write an anonymous inner class that implements ActionListener for each button
2)Write one actionPerformed() method and use the Event class's getSource() method to determine which button was pressed.

In either case, an action listener must be added to each button.

Please edit your post and wrap your code with code tags:
[code=java]
YOUR CODE HERE
[/code]
to get highlighting and preserve formatting.
(Note: I rarely try to read unformatted code)

**GregBrannon** · March 7th, 2014, 05:06 PM

I don't see your number buttons, but if you have them, then you'd add an ActionListener to each button, perhaps the same ActionListener. For example, if you had a "5" button with a better name, like fiveButton, then you'd add an action listener to it:

fiveButton.addActionListener( al );

where, 'al', is the ActionListener that contains the desired actionPerformed() method.

**alex1994** · March 7th, 2014, 05:18 PM

i used the following code to create my number 1 to 9
JPanel p2 = new JPanel();
p2.setLayout(new GridLayout(4, 3, 5, 5));

int num;
for (int iRow = 3; iRow>0; iRow--)
{
for (int iCol = 1; iCol<4; iCol++)
{
num = 3*(iRow-1) + iCol;

JButton btBody = new JButton("" + num);
btBody.setBackground(Color.WHITE);
btBody.setForeground(Color.BLUE);
p2.add(btBody);
}
}

but not sure if your piece of code will help me.

**GregBrannon** · March 7th, 2014, 05:27 PM

Please post your code correctly.

**alex1994** · March 7th, 2014, 05:38 PM

how do i add my code correctly

**GregBrannon** · March 7th, 2014, 05:44 PM

See the top of Post #2 or the bottom of Post #8.

**alex1994** · March 7th, 2014, 05:56 PM

do you want me to add all of the code i have done;

here is my code;

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package welcomegui;

/**
*
* @author am13aeg
*/
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class EX_7_2 extends JFrame
{
public EX_7_2()
{
setLayout(new BorderLayout(5, 10));

// create p1
JPanel p1 = new JPanel();
p1.setLayout(new BorderLayout(5, 10));

p1.add(new JTextField(), BorderLayout.NORTH);
JPanel p3 = new JPanel();

p3.setLayout(new GridLayout(1, 3, 5, 5));
JButton btBackspace = new JButton ("Backspace");
btBackspace.setBackground(Color.WHITE);
btBackspace.setForeground(Color.RED);

JButton btCE = new JButton ("CE");
btCE.setBackground(Color.WHITE);
btCE.setForeground(Color.RED);

JButton btC = new JButton ("C");
btC.setBackground(Color.WHITE);
btC.setForeground(Color.RED);

p3.add(btBackspace);
p3.add(btCE);
p3.add(btC);

p1.add(p3, BorderLayout.CENTER);

// create p4

JPanel p2 = new JPanel();
p2.setLayout(new GridLayout(4, 3, 5, 5));

int num;
for (int iRow = 3; iRow>0; iRow--)
{
for (int iCol = 1; iCol<4; iCol++)
{
num = 3*(iRow-1) + iCol;

JButton btBody = new JButton("" + num);
btBody.setBackground(Color.WHITE);
btBody.setForeground(Color.BLUE);
p2.add(btBody);
}
}

JButton btZero = new JButton ("0");
btZero.setBackground(Color.WHITE);
btZero.setForeground(Color.BLUE);

JButton btPlusMinus = new JButton ("+/-");
btPlusMinus.setBackground(Color.WHITE);
btPlusMinus.setForeground(Color.BLUE);

JButton btDot = new JButton (".");
btDot.setBackground(Color.WHITE);
btDot.setForeground(Color.BLUE);

p2.add(btZero);
p2.add(btPlusMinus);
p2.add(btDot);

JPanel p5 = new JPanel();
p5.setLayout(new GridLayout(4, 2, 5, 5));

JButton btBack = new JButton ("/");
btBack.setBackground(Color.WHITE);
btBack.setForeground(Color.RED);

JButton btsprt = new JButton ("sprt");
btsprt.setBackground(Color.WHITE);
btsprt.setForeground(Color.BLUE);

JButton btStar = new JButton ("*");
btStar.setBackground(Color.WHITE);
btStar.setForeground(Color.RED);

JButton btPercentage = new JButton ("%");
btPercentage.setBackground(Color.WHITE);
btPercentage.setForeground(Color.BLUE);

JButton btMinus = new JButton ("-");
btMinus.setBackground(Color.WHITE);
btMinus.setForeground(Color.RED);

JButton btOnex = new JButton ("1/x");
btOnex.setBackground(Color.WHITE);
btOnex.setForeground(Color.BLUE);

JButton btPlus = new JButton ("+");
btPlus.setBackground(Color.WHITE);
btPlus.setForeground(Color.RED);

JButton btEquals = new JButton ("=");
btEquals.setBackground(Color.WHITE);
btEquals.setForeground(Color.RED);

p5.add(btBack);
p5.add(btsprt);
p5.add(btStar);
p5.add(btPercentage);
p5.add(btMinus);
p5.add(btOnex);
p5.add(btPlus);
p5.add(btEquals);

JPanel p4 = new JPanel();
p4.setLayout(new BorderLayout(5, 10));
p4.add(p2, BorderLayout.CENTER);
p4.add(p5, BorderLayout.EAST);

add(p1, BorderLayout.NORTH );
add(p4, BorderLayout.CENTER);
}

public static void main(String[] args) {

EX_7_2 frame = new EX_7_2();
frame.setTitle("Calculator");
frame.setSize(350, 375);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOS E);
frame.setVisible(true);

}
}

--- Update ---

i do not get what you mean my add code tag, this is the first time i using a forum

**GregBrannon** · March 7th, 2014, 06:00 PM

What don't you understand about the instructions (and his note) that Norm gave in Post #8?

**alex1994** · March 7th, 2014, 06:05 PM

i have never heard of code tags have never used them therefore i dont know what i need to do to add the code tags

**Norm** · March 7th, 2014, 06:10 PM

Put the following before the code:
[code]

put the following after the code:
[/code]

Use the Preview Changes button in the Go Advanced area to see what happens to the post before saving.

**alex1994** · March 7th, 2014, 06:21 PM

her is the full code;

 
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
 
public class EX_7_2 extends JFrame 
    {
        public EX_7_2()
        {
            setLayout(new BorderLayout(5, 10));
 
            // create p1
            JPanel p1 = new JPanel();
            p1.setLayout(new BorderLayout(5, 10));
 
          p1.add(new JTextField(), BorderLayout.NORTH);
                    JPanel p3 = new JPanel();
 
         p3.setLayout(new GridLayout(1, 3, 5, 5));
         JButton btBackspace = new JButton ("Backspace");
         btBackspace.setBackground(Color.WHITE);
         btBackspace.setForeground(Color.RED);
 
         JButton btCE = new JButton ("CE");
         btCE.setBackground(Color.WHITE);
         btCE.setForeground(Color.RED);
 
         JButton btC = new JButton ("C");
         btC.setBackground(Color.WHITE);
         btC.setForeground(Color.RED);
 
          p3.add(btBackspace);
          p3.add(btCE);
          p3.add(btC);
 
          p1.add(p3, BorderLayout.CENTER);
 
 
 
          // create p4
 
          JPanel p2 = new JPanel();
          p2.setLayout(new GridLayout(4, 3, 5, 5));  
 
          int num;
          for (int iRow = 3; iRow>0; iRow--)
          {
              for (int iCol = 1; iCol<4; iCol++)
              {
                  num = 3*(iRow-1) + iCol;
 
                  JButton btBody = new JButton("" + num);
                  btBody.setBackground(Color.WHITE);
                  btBody.setForeground(Color.BLUE);
                  p2.add(btBody);
              }           
          }
 
         JButton btZero = new JButton ("0");
         btZero.setBackground(Color.WHITE);
         btZero.setForeground(Color.BLUE);
 
         JButton btPlusMinus = new JButton ("+/-");
         btPlusMinus.setBackground(Color.WHITE);
         btPlusMinus.setForeground(Color.BLUE);
 
         JButton btDot = new JButton (".");
         btDot.setBackground(Color.WHITE);
         btDot.setForeground(Color.BLUE);
 
         p2.add(btZero);
          p2.add(btPlusMinus);
          p2.add(btDot);
 
 
         JPanel p5 = new JPanel();
         p5.setLayout(new GridLayout(4, 2, 5, 5));
 
         JButton btBack = new JButton ("/");
         btBack.setBackground(Color.WHITE);
         btBack.setForeground(Color.RED);
 
         JButton btsprt = new JButton ("sprt");
         btsprt.setBackground(Color.WHITE);
         btsprt.setForeground(Color.BLUE);
 
         JButton btStar = new JButton ("*");
         btStar.setBackground(Color.WHITE);
         btStar.setForeground(Color.RED);
 
         JButton btPercentage = new JButton ("%");
         btPercentage.setBackground(Color.WHITE);
         btPercentage.setForeground(Color.BLUE);
 
         JButton btMinus = new JButton ("-");
         btMinus.setBackground(Color.WHITE);
         btMinus.setForeground(Color.RED);
 
         JButton btOnex = new JButton ("1/x");
         btOnex.setBackground(Color.WHITE);
         btOnex.setForeground(Color.BLUE);
 
         JButton btPlus = new JButton ("+");
         btPlus.setBackground(Color.WHITE);
         btPlus.setForeground(Color.RED);
 
         JButton btEquals = new JButton ("=");
         btEquals.setBackground(Color.WHITE);
         btEquals.setForeground(Color.RED);
 
         p5.add(btBack);
           p5.add(btsprt);
            p5.add(btStar);
             p5.add(btPercentage);
              p5.add(btMinus);
               p5.add(btOnex);
                p5.add(btPlus);
                 p5.add(btEquals);
 
                 JPanel p4 = new JPanel();
                 p4.setLayout(new BorderLayout(5, 10));
                 p4.add(p2, BorderLayout.CENTER);                
      p4.add(p5, BorderLayout.EAST);          
 
      add(p1, BorderLayout.NORTH );
      add(p4, BorderLayout.CENTER);
        }
 
 
 
 
public static void main(String[] args) {
 
        EX_7_2 frame = new EX_7_2();
        frame.setTitle("Calculator");
        frame.setSize(350, 375);
              frame.setLocationRelativeTo(null);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
 
}
}

**GregBrannon** · March 7th, 2014, 06:39 PM

Ahhhh. Thank you. (and Norm for making it clear)

Breaking out your number button code:

          int num;
          for (int iRow = 3; iRow>0; iRow--)
          {
              for (int iCol = 1; iCol<4; iCol++)
              {
                  num = 3*(iRow-1) + iCol;
 
                  JButton btBody = new JButton("" + num);
                  btBody.setBackground(Color.WHITE);
                  btBody.setForeground(Color.BLUE);
                  p2.add(btBody);
              }           
          }

A number of buttons are being made that are all called btBody, and they're local to the inner for loop. Since they're all assigned to btBody, there's really only one button. Those 2 conditions (one button and it is local) are working against you. You should create an array of JButtons - giving each one a separate name and identity - and the array of JButtons should be declared as an instance variable rather than a local variable.

Revise your code so that separate number buttons are created.

**Norm** · March 7th, 2014, 06:44 PM

Another option with the current code is to use one of the JButton class methods to get the String that is being shown by the button and use that to make decisions in the action listener method.

**alex1994** · March 7th, 2014, 07:38 PM

is that the only way, it it possible to add the actionlistener without removing the the code.

--- Update ---

norm how would i do that can you give me some help or an example code please

--- Update ---

can anyone help with the problem please.

**Norm** · March 7th, 2014, 07:39 PM

Post#9 gives an example. Something like this:

theButtonReference.addActionListener(theListenerReference);

Your button object reference variable is: btBody
You haven't defined an actionlistener or created an instance of it yet.
When an instance is created, replace theListenerReference with the reference to it.

**alex1994** · March 7th, 2014, 07:47 PM

Norm how do i create an instance for my code, i'm not quite familiar with this yet, could you please show me.

**Norm** · March 7th, 2014, 07:52 PM

You can create an instance of a class by using a new statement. This creates an instance of a JButton:

                  JButton btBody = new JButton("" + num);

Look at the tutorial: http://docs.oracle.com/javase/tutori...nlistener.html

**alex1994** · March 7th, 2014, 07:55 PM

could you give the the whole code which i will allow the number number to work please.

Thread: how do I add Action Listener to my code to make the calculator work

LinkBack

Thread Tools

Display

how do I add Action Listener to my code to make the calculator work

Related threads:

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Re: how do I add Action Listener to my code to make the calculator work

Similar Threads

[SOLVED] Anonymous inner class with Action Listener and Abstract Action

How to make a JPanel Form accept a method with action listener from the caller

add action listener problem

Action Listener

Need Help Action Listener....