while and action listener

[prisma flint]

I need to stop the while loop if i click on the panel , but the code doesnt even reach the actionlistener
Can somebody help

[cunning latch]

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[kindred slate]

I suggest you post the code in text form and in a codeblock.

[prisma flint]

should i post all of the code ?

[pearl eagle]

counter = System.currentTimeMillis() ; ```java

 while(buttonPressed == false) {
    
     if(System.currentTimeMillis() - counter > 500 && a == 0 ) {
         label.setText("PRESS TO START");
         counter = System.currentTimeMillis() ; 
         a = 1 ; 
         System.out.println(System.currentTimeMillis()) ; 

     }
     if(System.currentTimeMillis() - counter > 500 && a == 1) {
         label.setText(null);
         counter = System.currentTimeMillis() ; 
         a = 0 ; 
     }
 } ```
 
 panel.addMouseListener(new MouseListener() {

           @Override
        public void mouseClicked(MouseEvent e) {
               buttonPressed = true ;

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[kindred slate]

you don't update buttonPressed in your while loop

[prisma flint]

yeah becuase i want it to update only after presssing button

[kindred slate]

yeah but you have to update the state of buttonPressed within the loop otherwise you will never exit the loop

[prisma flint]

how can i do that bro

[kindred slate]

Damn, I just read that the MouseListener doesn't have to be integrated. Sorry for confusing you mate, Java GUI's are weird 😄

[prisma flint]

no probs bro , java sucks , but love it to death , so have to do this

[kindred slate]

Does your code print the currentTimeMillis() permanently?

[prisma flint]

nah nah , its just to know whats happening

[kindred slate]

Yeah, does it print?

I want to know what is happening too 😄

[prisma flint]

yes bro , that statement does work

the whole code blockwithin the while loop works

but it doesnt stop

[cunning sinew]

I suggest you make the buttonPressed an atomic variable

and put some kind of sleep in the while loop

it's likely that the thread is caching the buttonPressed value and never seeing that it got updated by the UI thread

or if not an atomic variable at the very least volatile

well actually I can't really see whether it's volatile. Is it?

[prisma flint]

i understood like 2% of what you wrote , idk what is atomic , volatile or anythgin

[prisma flint]

did the thraed even reach the buttonPressed = true statement ?

or does the thread get stuck in the while loop

[cunning sinew]

well without seeing the full context I can't tell exactly what is happening

from what I can see in the given code it's possible you never actually add the mouse listener to the panel because the statement to add it is after the while loop

why don't you move panel.addMouseListener above the while loop to begin with?

[prisma flint]

yoo that kinda works me gonna work on that

[cunning sinew]

still even if you do that you should make the variable atomic/volatile. Making a variable volatile is as simple as writing "volatile" before the type of the variable (only works for global variables) such as this:

 private volatile boolean foo=false;

[prisma flint]

what does this even do

[cunning sinew]

Events are fired on a thread separate from your main thread (either the UI thread or a thread specifically made for firing UI events, can't remember what was the case with javafx or swing or whatever. In any case the thread is different)

now when a thread is executing code it might choose to cache some variable to optimize

in other words if the variable buttonPressed has been false the last 20 times it was checked the compiler might decide to just make it false and not even check it

which is bad if it gets changed in another thread

the keyword "volatile" just tells the threads to not do such caching

and an atomic variable is just a volatile variable with the added benefit of two threads not being able to access the same variable at the same time. That's called atomicity. If they can access at the same time but no caching is guaranteed that's volatility

in general you should in most cases just make it atomic but in your case volatile will do the job

[prisma flint]

damn , thanks a lot bro , this prolly will make it qork

[cunning latch]

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[prisma flint]

dude all this shit happening just to run somw shitty code lmaoo

[cunning sinew]

yeah it can suck quite a bit

[prisma flint]

@cunning sinew you have any good resources to leanr abt java compilers and how it runs code

[prisma flint]

yes

[cunning sinew]

well I suppose if you want to know how things work in depth the java spec is probably the place to look

https://docs.oracle.com/javase/specs/

I can't say for sure though I've rarely read it to make sure of some stuff

[prisma flint]

thanks a lot mate

[cunning latch]

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If you are not, please ignore this message.
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[prisma flint]

hmm its fine

cheers