Can anyone help with this ActionListener in my java program?

Discussion in 'Mac Programming' started by maxtoncollins1, Mar 21, 2012.

  1. macrumors newbie

    Joined:
    Feb 16, 2012
    #1
    I'm trying to create a program to convert inches to centimeters. I made one that displayed the info in the console. (You'd type in a number of inches and it'd display how many centimeters that'd be) Now i'm trying to make one using java swing and i have a window that pops up but I am completely stuck on getting the action listener. Can anyone offer any advice or correct my code?
    Here's the code:
    Code:
    import javax.swing.*;
    
    import java.awt.Color;
    import java.awt.FlowLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    
    public class Cw extends JFrame implements ActionListener {
    
    	private JButton convert;
    	JTextArea text = new JTextArea(1,20);
    	private int conversion = 0;
    	
    	
    	
    	public Cw() {
    		setLayout(new FlowLayout());
    		setVisible(true);
    		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    		setSize(400,200);
    		convert = new JButton("Convert");
    		add(convert);
    		add(text);
    		convert.addActionListener(this);
    
    		
    	}
    
    
    
    public void actionPerformed(ActionEvent e) {
    	Object source = e.getSource();
    	
    		}
    
    		
    	}
    
    
     
  2. macrumors 603

    Joined:
    Aug 9, 2009
    #2
    What tutorial or book are you using? Or are you taking a class?


    Step 1 is to make the action do something simple, like show the text that's in the text field. That's a simple yet observable action. If you don't know how to do it, then you need to study how user input in Swing works. Not the button-click user input, just plain old text entered in a text field.

    Step 2 is to make the action validate the contents of the text field. I.e. is it numeric? Presumably you had to do that in the terminal oriented program.

    Step 3 is to convert the text to a number and perform the calculation. Again, you did that in the terminal program, right?

    Step 4 is to figure out how and where to display the result of the calculation. Study Swing again, and look for a component that can display text, or numbers converted to text.
     

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