Qt connect slot avec arguments

By Mark Zuckerberg

When you have a signal-slot connection, and the signal is emitted, it will "carry" the argument it's invoked with (well, so to speak). For example, QAbstractButton has a signal named toggled (bool) - it will always be sent together with this boolean information.

The signature of a signal must match the signature of the receiving slot. (In fact a slot may have a shorter signature than the signal it receives because it can ignore extra arguments.) This means that a signal of the form. signal(int, int, QString) can only be connected with slots with the following signatures The slot contains 2 arguments. void mySlot (int, int); I already connected a slot with one argument like this: QSignalMapper *signalMapper = new QSignalMapper ( this ); connect (act, SIGNAL (triggered ()), signalMapper, SLOT ( map ())); signalMapper->setMapping (act, ID); connect (signalMapper, SIGNAL (mapped ( int )), this, SLOT (goToSlot ( int ))); So I want to pass an argument to the slot This combination of C++11 lambdas and Qt 5's ability to connect a functor to a signal is such a useful and yet The other way to connect a signal to a slot is to use QObject::connect() and the SIGNAL and SLOT macros. The rule about whether to include arguments or not in the SIGNAL() and SLOT() macros, if the arguments have default values, is that the signature passed to the SIGNAL() macro must not have fewer arguments than the signature passed to the SLOT() macro. Default arguments in slot. If you have code like this: class A : public QObject { Q_OBJECT public slots: void someSlot(int foo = 0); }; The old method allows you to connect that slot to a signal that does not have arguments. But I cannot know with template code if a function has default arguments or not. So this feature is disabled. connect(buttonOne, SIGNAL(clicked()), this, SLOT(doSomething(double *))); @ This should work. But clicked() will not pass any data to your slot, so the pointer will be dangling. Plus you probably put the connect statement in a wrong place: it should be shown earlier, not on button click (but that depends on your design. [Qt] Slot avec plusieurs arguments × Après avoir cliqué sur "Répondre" vous serez invité à vous connecter pour que votre message soit publié. × Attention, ce sujet est très ancien.

Qt connect slot with arguments, qt connect slot other class . Group: Registered. Joined: 2021-02-19

Connecting Signals Using Keyword Arguments ¶ It is also possible to connect signals by passing a slot as a keyword argument corresponding to the name of the signal when creating an object, or using the pyqtConfigure () method of QObject. For example the following three fragments are equivalent: Traditional syntax: SIGNAL and SLOT() QtCore.SIGNAL() and QtCore.SLOT() macros allow Python to interface with Qt signal and slot delivery mechanisms. This is the old way of using signals and slots. The example below uses the well known clicked signal from a QPushButton. The connect method has a non python-friendly syntax.

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QSignal -- A QT Signal/slot for python. This project provides easy to use Signal class for implementing Signal/Slot mechanism in Python. It does not implement it strictly but rather creates the easy and simple alternative. Classes Signal. qsignal.Signal is the main class. To create a signal, just make a sig = qsignal.Signal and set up an 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.

when a Qt slot returns a QObject derived object to python when a Qt signal contains a QObject and is connected to a python function It is important that you call PythonQt::registerClass() for any QObject derived class that may become visible to Python, except when you add it via PythonQt::addObject() .

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Connect Qt signal and slot in a derived QObject constructor. 3. Why does adding a function argument cause a SLOT() to be unrecognised? 1. Qt - No matching

If I’m about to modify a slot function I might take an extra minute to look around since most IDEs can’t tell syntactically where it’s used in a SLOT() macro. In this case you have to search for it textually.) Thanks to C++11 lambdas and Qt’s ongoing evolution, these short slots can be replaced by a more succinct syntax. The emit line emits the signal valueChanged() from the object, with the new value as