Qt5 Signal Slot Connection Device
Qt5 Signal Slot Connection Speed Test

One key and distinctive feature of Qt framework is the use of signals and slots to connect widgets and related actions. But as powerful the feature is, it may look compelling to a lot of developers not used to such a model, and it may take some time at the beginning to get used to understand how to use signals and slots properly. However, since version 4.4, we can relay on auto-connections

From Qt 5.0 onwards, Qt offers two different ways to write signal-slot connections in C: The string-based connection syntax and the functor-based connection syntax. There are pros and cons to both syntaxes. The table below summarizes their differences.

While being better in many regards, the new connection syntax in Qt5 has one big weakness: Connecting overloaded signals and slots. In order to let the compiler resolve the overloads we need to use staticcasts to member function pointers, or (starting in Qt 5.7) qOverload and friends.
PyQt5 signals and slots Graphical applications (GUI) are event-driven, unlike console or terminal applications. A users action like clicks a button or selecting an item in a list is called an event. If an event takes place, each PyQt5 widget can emit a signal.

to simplify using this feature.
Back in the old days, signals and slots connections were set up for compile time (or even run time) manually, where developers used the following sentence:
this is, we stated the sender object's name, the signal we want to connect, the receiver object's name and the slot to connect the signal to.

Now there's an automatic way to connect signals and slots by means of QMetaObject's ability to make connections between signals and suitably-named slots. And that's the key: if we use an appropriate naming convention, signals and slots will be properly connected without the need to write additional code for that to happen. So by declaring and implementing a slot with a name that follows the following convention:
uic (the User Interface Compiler of Qt) will automatically generate code in the dialog's setupUi() function to connect button's signal with dialog's slot.
So back to our example, the class implementing the slot must define it like this:

We then write the method's implementatio to carry on an action when the signal is emitted:

Qt5 Signal Slot Connection Device

Qt5 Signal Slot Connection Speed Test

In brief, we have seen that by using automatic connection of signals and slots we can count on both a standard naming convention and at the same time an explicit interface for designers to embrace. If the proper source code implements such a given interface, interface designers can later check that everything is working fine without the need to code.