Question

void MyClass::onButtonClicked(){
    QPushButton *button = static_cast<QPushButton*>(sender());
    button->setDisabled(true);
    performSomeHeavyFunctionFor5or10seconds();
}

I want my button to be visually updated before that function (now it’s updated after). Should I use separate thread here? The second problem is that my program freezes while the function is executed.

Answer 1

I see two possibilities here:

1. Perform the heavy work in its own thread
2. Call QApplication::processEvents( QEventLoop::ExcludeUserInputEvents ) before you perform the heavy work in order to handle repaints etc. You can omit the flag by the way but I would leave it there so two fast clicks after one another can’t cause random behaviour