Why the value of a variable is wrongly pressed when a button is press in applet?

Question

I have a code in which there is a variable v whose default value is 0 . I also have 2 buttons : ok and nope. Using my code, when ok is pressed, the value of v should be 1 and when nope is pressed the value of v should be 2. But in both the cases it is printing the value of v as 2. Why is this? How can I correct it?

Edit : I did a minor mistake, I have corrected it, thanks to MadProgrammer.

import java.awt.*;
public class chk extends java.applet.Applet
{
    Button ok = new Button("OK!");
    Button nope = new Button("Nope");
    int v = 0;
    public void init()
    {
        setBackground(Color.white);
        add(ok);
        add(nope);
    }

    public boolean action(Event evt , Object arg)
    {
        if(evt.target instanceof Button)
        {
            check((Button)evt.target);
            return true;
        }
        return false;
    }
    public void check(Button b)
    {
        if(b == ok);
        {
            v= 1;
            repaint();
        }
        if(b == nope);
        {
            v=2;
            repaint();
        }
   }
   public void paint(Graphics g)
   {
        g.drawString(""+v,40,40);
   }
   }

All help is appreciated. Please let me know if I've made any mistakes.

Wow, I've not seen that style of code for...a very long time. Any reason why you're using AWT over Swing (or even FX)? — MadProgrammer, Jan 21 '14 at 11:21
1. did you debug check() ? 2. reference comparison (`b == ok`) is little dangerous — sanbhat, Jan 21 '14 at 11:21
1) Why code an applet? If it is due to spec. by teacher, please refer them to [Why CS teachers should stop teaching Java applets](http://programmers.blogoverflow.com/2013/05/why-cs-teachers-should-stop-teaching-java-applets/). 2) Why AWT rather than Swing? See my answer on [Swing extras over AWT](http://stackoverflow.com/a/6255978/418556) for many good reasons to abandon using AWT components. — Andrew Thompson, Jan 21 '14 at 12:30

MadProgrammer · Accepted Answer · 2014-01-21T11:42:11.503

6

Take a look at your if statements

    if(b == nope);

You've added a ; at the end of each statement. This means that both blocks of code within the {...} braces are being executed regardless of what the if statements might want. Remove the ; from the end of each statement

Ps- Unless you have a very particular need to use raw AWT, I'd consider taking a look at Swing or if you're really adventurous, JavaFX, as they are more modern GUI APIs

edited Jan 21 '14 at 11:42

answered Jan 21 '14 at 11:22

MadProgrammer

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1

@MadProgrammer, wow! I have been reviewing this code for a minute and have not seen this! – AlexR Jan 21 '14 at 11:25
2

@AlexR I'm not sure why it stood it, but it just did :P – MadProgrammer Jan 21 '14 at 11:27
@MadProgrammer, i really appreciate ur eyes , i have been studding java from 3 months , but i never did this kind of mistake and therefore never gave much attention to it , thanz a lot , i had created a much lengthier program and did the same mistake , my problem which i was not able to solve from 3 days has been solved :) – Darsh Jan 21 '14 at 11:31
@Darsh If you are satisfied with MadProgrammer's answer, you really should accept it by hitting the little green checkbox. – CodeChimp Jan 21 '14 at 13:10

score 0 · Answer 2 · answered Jan 21 '14 at 11:24

Don't use deprecated method and use an ActionListener instead :

ok.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                v = 1;
                repaint();
            }
});
nope.addActionListener(new ActionListener() {               
            @Override
            public void actionPerformed(ActionEvent arg0) {
                v = 2;
                repaint();
            }
});

score 0 · Answer 3 · answered Jan 21 '14 at 11:26

== COmparison is not considered good try something like this and As MadProgrammer said try removing ; after if and else.

if(b.getLabel().equals("OK!"))
     {
       v=1;
       repaint();
      }
if(b.getLabel().equals("Nope"))
      {
        v=2;
        repaint();
      }

Why the value of a variable is wrongly pressed when a button is press in applet?

3 Answers3