Qt connect signal slot twice

By Guest

A few weeks ago, we had an intern accidentally connect a signal to a slot more than once. The idea was that under one condition, you'd have the slot connected to the signal, and under another condition you'd disconnect it.

How Qt Signals and Slots Work - Woboq Qt is well known for its signals and slots mechanism. But how does it work? In this blog post, we will explore the internals of QObject and QMetaObject and discover how signals and slot work under the hood. In this blog article, I show portions of Qt5 code, sometimes edited for formatting and brevity. 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

Signals and Slots in Qt5 - Woboq

New Signal Slot Syntax - Qt Wiki Connecting in Qt 5. 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 ) ) );

In my case I am a bit stuck as I am getting the editFinished signal twice even when my slot handler is doing nothing. For a test, I have an array of QLineEdit which use a signalMapper to connect the editingFinished() signals to a single slot. The signalMapper passes the array index so I can see where the signal came from. eg:

Signals & Slots — Qt for Python 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. Why I dislike Qt signals/slots - elfery

Qt. Как использовать сигналы-слоты? — Toster.ru

signals-slots move - Qt Signals and Slot connected twice… What happens if the same signal and slot is connected twice? How is the mechanism handled?It's perfectly acceptable to connect the slot twice or even more times but when the signal gets fired your slot will be called for each connection you made which is probably not what you want. Qt Signals and Slots, Connecting and Disconnecting Qt connects widgets by means of a nice designed scheme based on the idea that objectS may send signalS of different typeS to a single object instance: This is a screenshot of the example code running. The main application creates dialogs A and B and then connects the signal from A to the signal slot...

Qt/C++ - Урок 024. Сигналы и слоты в Qt5

There is No Signal menu on screen when there is no input signal. 32 There is No Signal menu on screen when there is no input signal.