问题
I'm using a QSlider (v4.6) for input as well as to provide feedback to the user. For the feedback I will be calling the setValue method. I'm trying to find a signal that will fire only if the user modified the value. The valueChanged signal fires when the user changed the value as well as when I call setValue. sliderMoved only fires when the user drags the slider (not when using the keyboard). I checked the API docs and can't seem to find anything. Am I missing something? This seems something that would be common. If there is no other signal, how would you recommend that I simulate this functionality? Should I set a flag before calling setValue, disconnect and reconnect the signal every time I call setValue...?
回答1:
Good question, I checked the API and also couldn't find a signal that would be triggered only if value was modified by user. The workaround you proposed may be the only option, just keep in mind that you don't have to disconnect / connect all signals, just use QObject::blockSignals method:
slider->blockSignals(true);
slider->setValue(x);
slider->blockSignals(false);
Hope that helps.
来源：https://stackoverflow.com/questions/4146140/qslider-value-changed-signal