CODEWITHSUNDEEP
java
Joel
Joel

Reputation: 2721

unexpected behavior in printing string in loop

I don't understand why this is happening:

I have an integer being passed to a label object:

int NTURNS = 3;     
for (int i = NTURNS; i > 0; i--){
printTurns(i);  
buildBall(); 
}

and printTurns is this:

private void printTurns(int i){

 GLabel turns = new GLabel("" + i);
     remove(turns);     
 add(turns, (WIDTH - PADDLE_WIDTH), (BRICK_Y_OFFSET / 2));          
}

This will print the number of turns left in the game at the top. I have the remove(turns); there to remove the text so the next text won't overlap the old, but this is not working for some reason.

The numbers are stacking on top of eachother. Why is that?

Upvotes: 0

Views: 209

Answers (3)

Joel
Joel

Reputation: 2721

I had a hard time wrapping my head around Justin Niessner's answer, because I'm still new to constructors...however it did lead me to a method that worked for me. I'm putting my answer in, but I will mark his answer as correct:

private void setupGame(){

    GLabel turns = new GLabel("");   
    add(turns, (WIDTH - PADDLE_WIDTH), (BRICK_Y_OFFSET / 2));
    for (int i = NTURNS; i > 0; i--){
    turns.setLabel("" + i); 

    }
}

Upvotes: 0

Justin Niessner
Justin Niessner

Reputation: 245499

You've got a bit of a GLabel problem going on there. You're creating a new GLabel for each iteration through the loop.

You should create a single GLabel, add it to the form, and then call GLabel.setLabel() to change the text for each iteration of the loop. That should save you some headaches down the road.

Somewhere in your application's form initialization (maybe constructor?):

public class MyForm : GCanvas
{
    private GLabel _turns = new GLabel();

    public MyForm()
    {
        add(_turns);
    }

    private void printTurns(int i)
    {
        _turns.setLabel("" + i);
        _turns.setLocation(WIDTH - PADDLE_WIDTH), (BRICK_Y_OFFSET / 2));
    }
}

Upvotes: 3

Alex Martelli
Alex Martelli

Reputation: 882761

You're removeing the new string -- which isn't there yet -- not the old one! I.e., the second time around you're removeing "2" -- but there is no such string (as the first time you had added "3", not "2"!), so there's no effect. You need to remember the previous string you added, if any, e.g. in a private member variable, and remove that one string before you add the new one!

Upvotes: 2

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