Why Qt UI Application goes to 'Not Responding' state while the job has already moved to a worker thread?
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@jsulm I am not accessing the UI from the thread, if you look carefully you will see that everything passing from the worker thread are using signals and slot, otherwise, the application will not start.
setVisiblePg(true)this a signal which set the progress bar visible or hides it when accessing from the inside worker thread.
ui->progressBar->setMaximum(total);This not from other thread. Look Carefully please!
@BAHRAMUDIN-ADIL said in Why Qt UI Application goes to 'Not Responding' state while the job has already moved to a worker thread?:
@jsulm I am not accessing the UI from the thread, if you look carefully you will see that everything passing from the worker thread are using signals and slot,
that's a lie
QThread *thread = QThread::create([this]() { int p1 = 0; int p2 = 0; int p3 = 0; int p4 = 0; int p5 = 0; int p6 = 0; int p7 = 0; int p8 = 0; int p9 = 0; QString txt = ui->tfTestNumber->text(); //<<<<---------------- for (int i(0); i<data.size(); ++i) { // ....... loop through data emit setValue(i); // refresh progressBar } -
@BAHRAMUDIN-ADIL besides what @jsulm said,
you're wantonly negligent with other aspects of a thread as well.For example you access
datawithout a mutex! Data can be changed at any time or it might crash when both threads try to access the container.
if you're using cpp17 pass your create arguments!QThread *thread = QThread::create(myFunction, arg1, arg2);
Or use QtConCurrent the static function call on run allows arguments as well
also I see no reentrant checks. Multiple threaded functions could do exactly the same on the same data without mutex locks.Depending on how fast your "calculation" is and how big the
data.size()you're also flooding the main thread with signals, that can easily overwhelm it.@J.Hilk In the first, I don't need mutex because only one thread can access the data at the same time, my data is very big maybe 200,000,000.
But I don't know this: you're also flooding the main thread with signals, that can easily overwhelm it
If I don't use signal and slots, then what should I use to communicate between threads?
Thanks! -
@J.Hilk In the first, I don't need mutex because only one thread can access the data at the same time, my data is very big maybe 200,000,000.
But I don't know this: you're also flooding the main thread with signals, that can easily overwhelm it
If I don't use signal and slots, then what should I use to communicate between threads?
Thanks!@BAHRAMUDIN-ADIL You're emitting 10.000.000 signals, right? See "I am just generating 10,000,000 records of data".
If so, then you should reduce the amount of UI updates (your progress dialog). There is really no need to do it for each record. -
@J.Hilk In the first, I don't need mutex because only one thread can access the data at the same time, my data is very big maybe 200,000,000.
But I don't know this: you're also flooding the main thread with signals, that can easily overwhelm it
If I don't use signal and slots, then what should I use to communicate between threads?
Thanks!@BAHRAMUDIN-ADIL signal&slots is the way you should go.
Simply reduce the number of emits, via a modulo check for example, or a QElapsedTimer and only emit every 10 ms, etc.
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@BAHRAMUDIN-ADIL said in Why Qt UI Application goes to 'Not Responding' state while the job has already moved to a worker thread?:
@jsulm I am not accessing the UI from the thread, if you look carefully you will see that everything passing from the worker thread are using signals and slot,
that's a lie
QThread *thread = QThread::create([this]() { int p1 = 0; int p2 = 0; int p3 = 0; int p4 = 0; int p5 = 0; int p6 = 0; int p7 = 0; int p8 = 0; int p9 = 0; QString txt = ui->tfTestNumber->text(); //<<<<---------------- for (int i(0); i<data.size(); ++i) { // ....... loop through data emit setValue(i); // refresh progressBar } -
@J.Hilk You mean this:
emit setValue(i); // refresh progressBar??
It is a signal not directly set the value of the progressbar.
If I directly set it will throw an exception.@BAHRAMUDIN-ADIL This is where you're accessing UI class:
QString txt = ui->tfTestNumber->text(); -
@BAHRAMUDIN-ADIL This is where you're accessing UI class:
QString txt = ui->tfTestNumber->text(); -
@jsulm this is just getting the text, not setting text, and also it will be called the only once.
@BAHRAMUDIN-ADIL You still should avoid it. It may work or not.
And as already suggested: reduce the amount of signals you're sending for UI updates. -
@BAHRAMUDIN-ADIL You still should avoid it. It may work or not.
And as already suggested: reduce the amount of signals you're sending for UI updates.@jsulm Yes it will make sense, I will do this and see what happens.
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@BAHRAMUDIN-ADIL You still should avoid it. It may work or not.
And as already suggested: reduce the amount of signals you're sending for UI updates.@jsulm Thanks! The problem is just with emitig the signals very quickly.
