progress bar not updating during iterations but updating once the process is completed?

Christian Ehrlicher

Only one thing: You must not access or try to modify widgets outside the main gui thread. So fix your code and use proper signals/slots instead.

aravmadd

@Christian-Ehrlicher You mean since i am updating my progress bar with iteration number inside calib function(which is running in another thread) so my progress bar update is not working as intended right? . Even If i run my calib function in the same thread it is giving me same kind of output!

I didnt change anything in SIGNAL and SLOT implementation. (It was the same as mentioned in one of the screenshots above.)

Please correct me if i am wrong!.

Christian Ehrlicher

When you run your loop in the gui thread then the ui is blocked since you block the eventloop.

aravmadd

This post is deleted!

Christian Ehrlicher

Move your heavy calculation into an own thread as shown in the documentation and the examples there.

aravmadd

@Christian-Ehrlicher Hi!, I didnt change anything in the code as mentioned in the question. This comment is rather to get some more clarity for myself. I think i moved my heavy calculation part into the different thread. But inside this new thread i have two for loops and inside my second loop i want to pass iteration number by normalizing it to 0-100 to progressbar. So I am still confused why it is happening like this. And as per what i found is Threads can run an event loop.

Sorry for being dumb :-( . The more i go to documenation and some questions in stack and qt forum it is making me more confuse :-). May be because i am beginner :-)

Christian Ehrlicher

@aravmadd said in progress bar not updating during iterations but updating once the process is completed?:

So I am still confused why it is happening like this

Because you modify ui stuff from another thread which is not allowed. Use signals and slots as I already wrote 3 days ago.

aravmadd

@Christian-Ehrlicher Hi Thanks I am working on implementing it in worker class. I am trying to create worker class and do some intensive work there.

I have a small question here , how can i get information from ui into worker class? For example if i have some text in LineEdit i need to get this information in worker class.

jsulm

@aravmadd said in progress bar not updating during iterations but updating once the process is completed?:

how can i get information from ui into worker class?

via signals/slots

aravmadd

@jsulm Thanks it took me some time to figure it out on correct implementation of signals and slots.

Now its working.

What i did was

I ran the heavy calculation function in another thread using QtConcurrent.

Then from the heavy function i emitted signal , with the emitted signal i defined one slot(in my widget.cpp) which updates my progress bar.
Here is how it looks

connect(this, &Widget::updateProgress, this, &Widget::onProgressValueChanged);

After this i connected signal and slot properly it worked fine.

Initially i thought it is not working because the update is too fast that i cannot see real update in progress bar, then i only updated at 25 percent and 50 percent and 75 and 100 percent to my progress bar. Then i can see the progress in progress bar.