CODEWITHSUNDEEP
java
Ravin
Ravin

Reputation: 626

java beginner if/else if problem

something seems to be going wrong with the block of code that tries to set the String variable, as no matter what I do when I run the program, the Dialog Box always shows otto. Does anyone know what I'm doing wrong here?

Thanks, Ravin

import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JOptionPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

public class SmallTingz extends JFrame {
    private JLabel item1;
    private JTextField tf;
    private JTextField tf2;
    private JTextField tf3;
    private JPasswordField pf;

    public SmallTingz() {
        super("The Title");
        setLayout(new FlowLayout());
        JTextField tf = new JTextField("Cool Beans");
        JTextField tf2 = new JTextField("UnCool Beans");
        JTextField tf3 = new JTextField("Hot Beans");
        JPasswordField pf = new JPasswordField("password");

        add(tf);
        add(tf2);
        add(tf3);
        add(pf);

        thehandler handler = new thehandler();
        tf.addActionListener(handler);
        tf2.addActionListener(handler);
        tf3.addActionListener(handler);
        pf.addActionListener(handler);
    }

    private class thehandler implements ActionListener {

        public void actionPerformed(ActionEvent event) {
            String string;          
            if (event.getSource() == tf)
                string=String.format("field1: %s", event.getActionCommand());
            else if (event.getSource() == tf2)
                string=String.format("field2: %s", event.getActionCommand());
            else if (event.getSource() == tf3)
                string=String.format("field3: %s", event.getActionCommand());
            else if (event.getSource() == pf)
                string=String.format("passfield: %s", event.getActionCommand());
            else
                string="otto";

            JOptionPane.showMessageDialog(null, string);        
        }
    }
}

Upvotes: 3

Views: 2483

Answers (2)

Eric
Eric

Reputation: 19863

Two things.

First, I always use brackets everywhere I can with else if

if(...){
//do stuff
}
else
{
  if(...)
  {
  // other stuff.
  }
}

It makes it much easier to read. Readability is one of the most important aspect of writing code.

Second, it is a very good opportunity to learn how to use the debugger. I suspect that you are using eclipse. Click in the margin of if(event.getSource()==tf) A small red dot should appear, this is a breakpoint. Now run your code in debug mode.

The execution should stop at that line. Hover your mouse cursor over the "event" variable. You should see a popup that will show you a description of that object.

This should help you understanding why GetSource() does not return a pointer to your JTextField(s)

Maybe you'll see that tf are null like user802421 said.

Upvotes: 1

user802421
user802421

Reputation: 7505

In your SmallTingz() constructor, remove all variable declarations. Your declarations is hiding the member variables.

Change

JTextField tf = new JTextField("Cool Beans");
JTextField tf2 = new JTextField("UnCool Beans");
JTextField tf3 = new JTextField("Hot Beans");
JPasswordField pf = new JPasswordField("password");

to

tf = new JTextField("Cool Beans");
tf2 = new JTextField("UnCool Beans");
tf3 = new JTextField("Hot Beans");
pf = new JPasswordField("password");

Upvotes: 12

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