Qt 4.3: Signals and Slots Signals and Slots. In Qt, we have an alternative to the callback technique: We use signals and slots. A signal is emitted when a particular event occurs. Qt's widgets have many predefined signals, but we can always subclass widgets to add our own signals to them. A slot is a function that is called in response to a particular signal. Terminate QThread correctly | Qt Forum You stopped the loop in ThreadWorker, but you didn't stop the loop in QThread. As @J-Hilk said, you need to call threadController->quit() too. @Andrea said in Terminate QThread correctly: I've read the QThread Basics docs and also had a look on StarckOverflow and the Qt forum, but still having the doubt. Signals and Slots | Introduction to GUI Programming with ... PyQt is more versatile than C++/Qt in this regard, because we can connect not just to slots, but also to any callable, and from PyQt 4.2, it is possible to dynamically add "predefined" signals and slots to QObjects. Let's see how signals and slots works in practice with the Signals and Slots program shown in Figure 4.6. qt4 - Qt 4.5 - Is emitting signal a function call, or a ...
Effective Threading Using Qt - John's Blog
Signals and Slots - Qt Documentation 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. How to process events during infinite loop in Worker I've created a Worker object in Qt to process video input indefinitely, and then move it into a QThread to keep the UI thread going. The problem is, I designed it such that the video capture function runs in an infinite loop until interrupted by a flag, and the flag was supposed to be set by a slot in the Worker object, but since the Worker object is inside the infinite loop, it never Qt 4.3: Signals and Slots 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. Terminate QThread correctly | Qt Forum
Signals and Slots in Depth | C++ GUI Programming with Qt4 ...
2.4.3 Events and event handling, signals and slots | GEOG 489 ... QT’s widgets have predefined slots so that it is possible to directly connect a signal of one widget to a slot of another widget. For instance, the “clicked” signal of a button can be connected to the “clear” slot of a text widget, such that the text of that widget is cleared whenever the button is clicked. Signals and Slots in Depth | C++ GUI Programming with Qt4 ...
How to process events during infinite loop in Worker
Signals and Slots - PyQt Programming - pythonstudio.us These signals can be connected to any callable, that is, to any function or method, including Qt slots; they can also be connected using the SLOT() syntax, with a slotSignature. PyQt checks to see whether the signal is a Qt signal, and if it is not it assumes it is a Python signal.
Signals and Slots - Qt Documentation
Вопрос, система сигналов-слотов в Qt потокобезопасная? У меня в приложении грубо говоря есть два основных потока, каждый из них живет своей жизнью и не зависит друг от друга. Но иногда из одного потока мне нужно передать сообщение в другое, либо наоборот. c++ - Qt Signal Slot Architecture Unwanted Infinite Loop… c++ qt signals-slots | this question edited Dec 23 '13 at 12:45 asked Dec 23 '13 at 12:16 Cahit Burak Küçüksütcü 198 3 20 As a similar with BartoszKP's second solution, I've found a solution too. QObject has a blockSignals() method to prevent emitting inner signals. Qt na mobilních zařízeních
Effective Threading Using Qt. Introduction. Over the years using Qt I’ve seen a lot of difficulty using threads with Qt. Threads can be difficult and Qt provides a lot of ways to make threads easy to work with. Still basic / direct / low level threading (I’ll just call this basic) is often seen as difficult with Qt. It really isn’t though. Multithreading Technologies in Qt | Qt 5.12 Move the worker to the new thread. Send commands or data to the worker object over queued signal-slot connections. Permanent: Repeatedly perform an expensive operation in another thread, where the thread does not need to receive any signals or events. Write the infinite loop directly within a reimplementation of QThread::run(). Start the thread ... How to Use Signals and Slots - Qt Wiki A developer can choose to connect to a signal by creating a function (a slot) and calling the connect() function to relate the signal to the slot. Qt's signals and slots mechanism does not require classes to have knowledge of each other, which makes it much easier to develop highly reusable classes. New Signal Slot Syntax - Qt Wiki There are several ways to connect a signal in Qt 5. Old syntax. Qt 5 continues to support the old string-based syntax for connecting signals and slots defined in a QObject or any class that inherits from QObject (including QWidget) connect( sender, SIGNAL( valueChanged( QString, QString ) ), receiver, SLOT( updateValue( QString ) ) );