Qt: Return value of signal works, why is the official doc saying it is impossible / forbidden? - Stack Overflow - Stack Overflow … E.g. with Qt::SingleConnection there is no risk of multiple slots, with Qt::BlockingQueuedConnection there is only one return value at a time. "Never have a return value" (doc) is different to use wisely IMHO. All the above true, there might be side effects, but still many use cases where return values … c++ - QT signal and slot function signature - Stack Overflow Your slots can return a value. However, if the slot is connected to a signal and called when the signal is emitted, the return value will be ignored. But the slot is a normal member function and can be called like any other function. In this case, the return value can be used by the caller. This is said in the document you link to : Function with Signals & Slots | Qt Forum
Debugging Qt's signal-slot connections What do you do if you think that you've ... If need be, ensure that the connection succeeds by testing its return value (it ...
Signals and Slots in PySide - Qt Wiki Retrieved from "https://wiki.qt.io/index.php?title=Signals_and_Slots_in_PySide&oldid=33227" Can Qt signals return a value? - Stack Overflow OK. So, I did a little more investigating. Seems this is possible. I was able to emit a signal, and receive value from the slot the signal was ...
Application Example — Qt for Python
[Quick PyQt5 : 1] Signal and Slot Example in PyQt5 – Manash's blog
Signals and slots are used for communication between objects. The signals and slots mechanism is a central feature of Qt and probably the part that differs most from the features provided by other frameworks. The minimal example requires a class with one signal, one slot and one connection: counter.h
Therefore slot return types are useless when invoked through a signal (even though you can still use them when you invoke a slot directly, ie if it's a member function). That being said, you can capture ui or even better plainLineEdit by reference or by address in your slot (ie if it's a lambda) and set correctly the string from there. qt - My signal / slot connection does not work - Stack Overflow My signal / slot connection does not work. ... Always check return value of connect method ... How to disconnect a signal with a slot temporarily in Qt? 0. Signals & Slots | Qt 4.8 Signals and slots are loosely coupled: A class which emits a signal neither knows nor cares which slots receive the signal. Qt's signals and slots mechanism ensures that if you connect a signal to a slot, the slot will be called with the signal's parameters at the right time. Signals and slots can take any number of arguments of any type. c++ - Qt - Return value when signal is emitted? - Stack Overflow
Support for Signals and Slots — PyQt 5.11.1 Reference Guide
How Qt Signals and Slots Work - Part 3 - Queued and Inter ... DirectConnection: call the slot as seen in Part 1 */ So in this blog post we will see what exactly happens in queued_activate and other parts that were skipped for the BlockingQueuedConnection. Qt Event Loop. A QueuedConnection will post an event to the event loop to eventually be handled. How to Use QPushButton - Qt Wiki The following simple code snippet shows how to create and use QPushButton. It has been tested on Qt Symbian Simulator. An instance of QPushButton is created. Signal released() is connected to slot handleButton() which changes the text and the size of the button. To build and run the example: Create an empty folder
@gabor53 You should read again about Qt signals/slots. They are used for asynchronous communication and to react on user interactions. That means if you connect the clicked() signal of a button to a slot that slot will be called when user presses the button. Can Qt signals return a value? - ExceptionsHub Nov 22, 2017 · Questions: Boost.Signals allows various strategies of using the return values of slots to form the return value of the signal. E.g. adding them, forming a vector out of them, or returning the last one. The common wisdom (expressed in the Qt documentation [EDIT: as well as some answers to this question ]) is that no Sending Python values with signals and slots - FrontPage