Just right-click any dock title-bar, or any tool-bar or menu-bar. /***** ** ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). Consider a card game. So this is like calling doSomething in the next event. It is provided to keep old source code working. 详细说明 QSignalMapper 类捆绑来自可识别发送者的信号。. removeItem, QtCore. Toggle table of contents sidebar. The class supports the mapping of particular strings or integers with particular objects using setMapping(). For strings and integers, you can use QSignalMapper. Several years ago I wrote a short piece on QSignalMapper to give a quick example of how it can be used. The main focus is on how the extra input panel can be used to input text without the need for a real keyboard or keypad. The QSignalMapper is used to re-emit signals with optional parameters. Types used in signal/slot connections must be fully 'scoped' because the method call is converted into text, so your connection call should look like this: QObject::connect (&myClassA, SIGNAL (theSignal (namespace::myClassA::aStruct)), &myClassB, SLOT (theSlot (namespace::myClassA::aStruct))); You'll probably have to. I have read a lot of theory about QSignalMapper,Welcome to the MadMapper Tutorial Series!THE PROJECTOR I USED: Link: Answer. This signal is emitted when map() is signalled from an object that has a string mapping set. Después de recibir el clic de botón, QSignalMapper notifica a otro control para su procesamiento. QSignalMapper * mapper = new QSignalMapper (this. } Now the place where you write QTimer::singleShot (0, this, SLOT (doSomething ())); might be inside some processing event. Below is an example of the use of QSignalMapper in Qt4/5. 这个思想是：希望能够在信号关联中直接传递一个参数！直接用信号槽无法实现. 15. I’ve since found another couple of places in my code that benefit from QSignalMapper since it handles more than QString. h. @t-vanbesien said in no matching member function for call to 'connect':. I think you can use this method: [protected] int QObject:: senderSignalIndex () const. qml allocated and removed from a c++ class keyboardManager. QListWidget uses an internal model to manage each QListWidgetItem in the list. We strongly advise against using it in. connect (signalMapper. If called outside of a slot activated by a signal, -1 is returned. The syntax of a lambda expression is the following: [captured variables] (arguments) {. mapped [int]. The syntax of a lambda expression is the following: [captured variables] (arguments) {. QtCore. ViewObject. You can connect a signal to a slot with connect (). Either connect SIGNAL(finished(void)) to SLOT(HttpImageFinished(void)), or connect SIGNAL(finished(QCustomWidget *)) to. But I am not able to exactly place, which signal is to be called for which slot. Qt’s model/view architecture provides a standard way for views to manipulate information in a data source. The workaround is to explicitly specify a signal that is compatible with map (). ** ** Contact [email protected] QSignalMapper is a member variable, and each QCheckBox connects its clicked signal to the map() slot of QSignalMapper. map () being called from a proxy rather than new-style connections. self. Puis mets-toi à jour en utilisant une fonction lambda à la place de tout cet attirail de QSignalMapper. We would like to show you a description here but the site won’t allow us. Hi, I have a slot that I'd like to connect to. PyQt and QSignalMapper/lambdas - multiple signals, single slot. QSignalMapper Example Revisited. 使用QSignalMapper确定信号的发送者（针对多个发送者的情况） 如果有多个对象都可能发送信号，并且我们希望根据信号发送者来采取不同的操作，可以使用QSignalMapper类。该类可以将多个对象与相应的信号关联起来，并通过sender()方法确定信号的发送者。Many examples show how to do this with QSignalMapper, but it is not applicable when the signal carries a parameter, as with combobox. In python this is actually not even an issue, and that class is not really required: you can just use functools. To handle the different types of data associated with each option, then in QAction the value is stored and accessed using setData () and data (), respectively. This is less costly and will simplify the code. mapper = new QSignalMapper ( this ); connect ( mapper, SIGNAL (mapped. main. QTimer::singleShot - forward parameter to SLOT called. This is useful for QML applications which may refer to the emitted values by name. 0. You could simply assign a value to the button with a map ( QMap, std::map) or through a dynamic property: @tanmayb, it is already a different question. Detailed Description. I need to implement a simple message bus: One process only thus no need do D-Bus. QSignalMapper类可以看成是信号的翻译和转发器。. Share. ** ** Contact info@trolltech. Related questions. Im having troubles seeing the readyRead () signal from a bound UDP socket. I want to use a QSignalMapper to distinguish between each QButton and it's corresponding QLineEdit, so if Button1 is clicked, I want to set the text in Edit1. Instead of accepting an int as an argument, use sender() to determine which button is the source. The signals and slots mechanism is type safe: The signature of a signal must match the signature of the receiving slot. Share. Then, create a standalone. 它可以把一个无参的信号翻译成带int参数、QString参数、 QObject* 参数或者QWidget *参数的信号，并将之转发。. PySide6. If you have to use a QSignalMapper anyway, you have to use the signal QSignalMapper::mapped(QWidget*). You can limit the size of the read buffer using setReadBufferSize () . and I assume you initialized the "signalMapper = new QSignalMapper (this)" in the MyApp constructor. Algunos amigos pueden preguntar, ¿por qué es tan problemático y. Main Page; Packages; Classes; Class List; Class Index; Class Hierarchy; Class MembersThe PySide. QBitmap is only a convenience class that inherits QPixmap, ensuring a depth of. [slot] void QSignalMapper:: map (QObject *sender) This slot emits signals based on the sender object. Felgo Services App Development Mobile and desktop application development Embedded Development Applications and companion apps for embedded Qt Consulting and Development Ask our help for anything Qt related Qt Trainings and Workshops Book trainings and tailored workshops Qt 6 Porting and Migration Migration, modernization,. Related questions. QObject::connect () works like this (in the general case, not using lambda): connect (obj1, obj1_signal, obj2, ob2_slot) Since there is no signal clicked (int, int) in the class QPushButton (which I assume you are using), it cannot be use for the connection. The class supports the mapping of particular strings or integers with particular objects using setMapping(). 2. I've taken the liberty to add example code to your answer. @Maaz-Momin said in QPushButton "pressed" signal emitting twice when moving mouse: Remember you need to press and move your mouse on a button ("F1" or. It only want to work with integers. One of the cool things introduced in Qt5 is a new overload for the QObject::connect () method: C++. If you want to do that, you need to either manually connect everything or otherwise do what this guy described: Can QSignalMapper be used to re-emit signals with multiple parameters? and reimplement QSignalMapper for your specific case. fix deprecated warning int QWheelEvent::delta() break macOS build (Page 1) — Code — QElectroTech —The QSignalMapper class bundles signals from identifiable senders. ** Contact: ** ** This file is part of the QtCore module of the. map ()This method is also a Qt slot with the C++ signature void map(). py. Simple painter application based on Qt Widgets. mapper, QtCore. The class supports the mapping of particular strings or integers with particular objects using setMapping(). If you want to do that, you need to either manually connect everything or otherwise do what this guy described: Can QSignalMapper be used to re-emit signals with multiple parameters? and reimplement QSignalMapper for your specific case. You may have to register before you can post: click the register link above to proceed. : The QSignalMapper class is provided for situations where many signals are connected to the same slot and the slot needs to handle each signal differently. Viewed 82 times 0 I'm making an application which will be able to program my board. For example, if your product is called Star Runner and your company is called MySoft, you would construct the QSettings object as follows: settings = QSettings("MySoft", "Star Runner")I use a QWidget in a Qthread and I had to modify the image in a Qlabel of multiple object. Push (click) a button to command the computer to perform some action, or to answer a question. void mySlot(int, int); I already connected a slot with one argument like this: QSignalMapper *signalMapper = new QSignalMapper(this); connect(act, SIGNAL(triggered()), s. In the following example, clicking on the QML object makes the C++ object print a message, and vice-versa. This function was introduced in Qt 5. In other words (from the documentation):. The class supports the mapping of particular strings or integers with particular objects using setMapping(). Now, consider discarding those cards, to draw new ones. The Property System. 2. QtCore. 在. Possible solution is connect QSlider signal sliderReleased (), emitted when the user releases the slider with the mouse, with QSignalMapper map () and store sliders id with pointer on some list. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. connect(x_slider[0], SIGNAL(valueChanged(int)), this, SLOT(slider_x(int))); but as I don't want to create a slot to every slider in the x_slider array the int received in slider_x slot should be in this case a 0. I have. #include <QApplication> #include <QtGui> #include <QVBoxLayout> #include <QSignalMapper> #include <QCheckBox> #include <QDebug> class CheckableCheckBox : public. In this example, the QSignalMapper object is created and connected to the clicked () signal of two buttons. 1. In this way the slot associated to the signal mapper is invoked only when the checkbox is checked and not when it is unchecked. This was particularly true in older versions of the software, that is, and relied on Qt 4. Looks like all good. in the class definition . 它可以把一个无参的信号翻译成带以下4种参数的信号再转发：int、QString、 QObject以及QWidget 。. 3. partial, lambdas, or custom signals. PreferencesRole. connect (self. Below is an example of the use of QSignalMapper in Qt4/5. Detailed Description. There is no such signal mapped (const QPushButton&). ** **/ #ifndef QSIGNALMAPPER_H #define QSIGNALMAPPER_H #ifndef QT_H #include "qobject. Is there a more correct way to do it? e. Each of the above functions has a blocking variant that returns the final result instead of a. Cards are drawn from a deck and displayed on screen. mousePressEvent = lambda event : edit. c++; qt; signals; mapper; Share. QButtonGroup provides an abstract container into which button widgets can be placed. Here is my code for the SignalMapper: In my header:. value ("image"). So I'm dynamically creating QPushButton objects and then mapping them to emit a signal. The QSignalMapper class bundles signals from identifiable senders. But i know it is possible to do it with strings. 我无法将信号映射（QObject*）以触发. QImage is designed and optimized for I/O, and for direct pixel access and manipulation, while QPixmap is designed and optimized for showing images on screen. . Python QSignalMapper - 59 примеров найдено. 1 Answer. readAll(inp) # restore from string. QT supports a collection of events through its object QSignalMapper as demonstrated below: signalMapper = new QSignalMapper(this); signalMapper->setMapping(taxFileButton, QString("taxfile. Unfortunately, all attempts of making this used QSignalMapper successfully in a similar situation. There are the ways to solve that: 实际上有一种其他技术可以用来获得包装函数和参数的效果。它使用QSignalMapper类，其使用的示例在第9章中显示。 在一些情况下，可以将槽称为信号的结果，并且在槽中直接或间接执行的处理导致最初称为槽的信号被再次调用，导致无限循环。 Worth noting (2018, Qt5, C++11) that QSignalMapper is deprecated. map) checkbox_2. I have a QSpinBox and I would like to connect it to a slot with 2 parameters when clicking on the arrows. In the following example, clicking on the QML object makes the C++ object print a message, and vice-versa. QSignalMapper is the best solution to connect multiple signals to the same slot. // create the actual socket. The class supports the mapping of particular strings or integers with particular objects using setMapping(). signal keyboardOpening signal keyboardOpened signal keyboardClosing signal. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. to get the ID (can be 1 to 16) and know which ID did kick off the singleShot. David, thanks for your help. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. The QSignalMapper class bundles signals from identifiable senders. The. There are three points to keep in mind to use QSignalMapper:. Im creating QSliders and QLabels in my Program and i want to connect them so when I'm changing the Slider the Value should be shown within the label. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. A button can be made the default button in a dialog by means of setDefault () and setAutoDefault () . I have had a look to the logfile of our application, started/cleared yesterday morning. This is our current code -. QSignalMapper does not update parameter after choosing file. Since a slot has to have the same signature than the connected signal, on_steps_returnPressed becomes on_steps_returnPressed(QWidget*) (cast the parameter to a QLineEdit):The QSignalMapper class bundles signals from identifiable senders. QSignalMapper class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the. Is there any relatively simple way for it? c++; qt; enums;Here is an easy way to get the 3D representation of an object. QSignalMapper class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. Tutorials. See: QMainWindow::createPopupMenu. In other words (from the documentation): This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to. The application name is fetched from the Info. If you need to know both value and sender you either can use some internal class mapping, or use QObject * mapper and then cast QObject * to slider. QSignalMapper can not be used for that, but the class is quite simple to re-implement and specialize for your needs. map) Tonight's PyQt snapshot will be smarter about finding a usable Qt slot before deciding that it needs to. ) Share. Constructs a QSignalMapper with parent parent. void myclass::deleteButton (int i) { delete (Buttons. Use mapped (QWidget*) and change your slot to have the same signature: button_pushed (QWidget*). What i want to achieve is a little different. 然后可以将. The overloads are obsolete in Qt 5. The technique involves reimplementing the qt_metacall method yourself. But is there a way to use a QStringList? The idea would be. Create Button actually looked like this: void Widget::createButton (const QString &text, int x, int y, const char *member, QString &data) { QPushButton *button = new QPushButton (this); signalMapper = new QSignalMapper. How to map to overload Qt slot. clicked. This class collects a set of parameterless signals, and re-emits them with integer, string. – SPlatten. There are the ways to solve that: If Qt4 is used then I'd suggest to implement your own. Use the setMapping method to add a mapping between a sender. mapper. J 1 Reply Last reply 10 May 2018, 05:28 0. QSignalMapper *mapper = new QSignalMapper. The setMapping. map ()作为. I ha to use repaint fonction to force th label to update regulary the display. For example, we change the border to grey and the chunk to cerulean. QSignalMapper * mapper = new QSignalMapper (this);. Connect and share knowledge within a single location that is structured and easy to search. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. Signals and slots are made possible by Qt’s meta-object. ** **/ #ifndef QSIGNALMAPPER_H #define QSIGNALMAPPER_H #ifndef QT_H #include "qobject. 2 [Русский] Qt Core ; QSignalMapper Class8. QSignalMapper taken from open source projects. 3 Answers. plist JavaScript jpegtran jQuery JSON Leaflet library macOS Mac OS X maps OpenCV open source optimization php point cloud QGraphicsItem QGraphicsScene QGraphicsView. The QSignalMapper class bundles signals from identifiable senders. Graphical user interface programming is a domain that requires both runtime efficiency and a high level of flexibility. 画像のような複数のUIの操作に応じて一つのUIを更新する処理は QSignalMapper が担ってきました。 しかし Qt5 では QSignalMapper は非推奨とされ、 ラムダ式 への置き換えが推奨されます。 そこで、実際にどのように置き換えていくかをここに記録します。 従来の QSignalMapper を…QSignalMapper puede entenderse como un transpondedor, ¿qué deberíamos decir? Por ejemplo, la ranura de respuesta de un clic de botón está vinculada a QSignalMapper. The class supports the mapping of particular strings or integers with particular objects using setMapping (). trigger () behaves correctly, and not act_str. Here's a dummy widget to illustrate that. According to the QT documentation QWorkspace should be replaced with QMdiArea. Typical buttons are OK, Apply, Cancel, Close, Yes, No and Help. Since your "load" and "return to main menu" signals are. #. When a widget is used as a container to group a number of child widgets, it is known as a composite widget. 1 Reply Last reply 10 May 2018, 05:37 0. The QWidget class provides the basic capability to render to the screen, and to handle user input events. QSignalMapper taken from open source projects. Much thanks to you both. This is an overloaded function. My. I currently have a qml object keyboard. QSignalMapper extracted from open source projects. The class supports the mapping of particular strings or integers with particular objects using setMapping (). Composite Widgets#. With QSignalMapper, trivial change in a . [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. Since then, Qt5 has been released and C++11 is now A Thing. b1. The specified plugin paths can be retrieved using the pluginPaths () function. QSignalMapper does not provide functionality to pass signal parameters. But I have problem, I don't know how to assign string to a button. 1. I have read a lot of theory about QSignalMapper, QSignalMapper类可以看成是信号的翻译和转发器。. Additionally, double check that your connects are being made by. map(sender) Parameters: sender – PySide6. Before Qt 5. QT之QSignalMapper（可以理解为转发器，多个按钮绑定到一个Edit上，且能分辨。每个单独连接的话，反而麻烦） 简述 QSignalMapper我们可以理解为转发器，此话怎讲呢？比如，按钮点击的响应槽，绑定到QSignalMapper上，QSignalMapper收到按钮的点击后，又通知到另外的控件. By voting up you can indicate which examples are most useful and appropriate. The solution is to connect the clicked signal of the different buttons to the mapper directly (rather than through your LoadGameMenu. This class collects a set of parameterless signals, and re-emits them with integer or string parameters. (Going forward the goal will be to. About QSignalMapper's slot/signal names, agree they can be somewhat confusing: map() is QSignalMapper's fixed "receptacle" slot name, setMapping() is the important proxy/augmentation data setup, and mapped() is the fixed outgoing signal name. The class supports the mapping of particular strings or integers with particular objects using setMapping(). Menu items may be removed with removeAction (). 实际上有一种其他技术可以用来获得包装函数和参数的效果。它使用QSignalMapper类，其使用的示例在第9章中显示。 在一些情况下，可以将槽称为信号的结果，并且在槽中直接或间接执行的处理导致最初称为槽的信号被再次调用，导致无限循环。*/ QObject * QSignalMapper:: mapping (QObject * object) const {Q_D (const QSignalMapper); return d-> objectHash. Method Documentation QSignalMapper. " GitHub is where people build software. Simply use a QMap<QObject*,ValueStruct>, where ValueStruct keeps your arguments. It can be subclassed to tailor the look and feel. From the link: "This class is obsolete. There are actually two ways to implement a virtual keyboard with Qt: in-process and out-of-process. } Ignoring the “captured variables” part for now, here is a simple lambda which increments. QtCore. Since then, Qt5 has been released and C++11 is now A Thing. Signals and slots are used for communication between objects. You can rate examples to help us improve the quality of examples. To avoid such things - use the new signal slot syntax properly described in the documentation. Suppose you have three push buttons that determine which file you will open: "Tax File", "Accounts File", or "Report File". dheerendra Qt Champions 2022 14 Jan 2019, 22:11. void QSignalMapper::setMapping ( const QObject * sender, const QString & identifier ) [virtual] This is an overloaded member function, provided for convenience. QAction. If I correctly understood, each QGraphicsItem has special unique QComboBox. 1. connect (self. 应用场景一般是：你有一些信号，这些信号对应的槽函数内容都差不多，最. Calling QComboBox* combo = (QComboBox* )sender() in the slot fails, presumably because sender() is now the QSignalMapper. mapper = new QSignalMapper( this ); connect( mapper, SIGNAL(mapped(QWidget*)), workspace, SLOT(setActiveWindow(QWidget*)) ); I read QSignalMapper can be replaced with lamdas but how in this case? If i understand right mapper forwards all the signals from this to workspaces active window? The trade-off with QSignalMapper is that you gain information about the source of the signal, but you lose the original arguments. Dynamic Signals and Slots by Eskil A. We strongly advise against using it in new code. The QSignalMapper is used to re-emit signals with optional parameters. The object's mapped widget is passed in widget. The QSignalMapper class bundles signals from identifiable senders. This is useful when multiple objects need to send a signal to the same slot, but with different parameters. Since I need to pass some arguments to sendRequest function I guess I have to use QSignalMapper but as QSignalMapper::setMapping can be used straightforwardly only for int and QString, I cannot figure out how to implement this. We create a Window class with an almost identical user interface, except that, instead of providing a spin box so that each person's age can be entered, we provide a combo box. addObject("Part::Box", "myBox") s = box. Detailed Description. The use of QSignalMapper is not necessary in Qt 5, and is optional in Qt 4. Just right-click any dock title-bar, or any tool-bar or menu-bar. You shouldn't need to use QSignalMapper with QDialogButtonBox. How in PyQt connect button to a function with a specific parameter? 11. All the buttons provided by Qt ( QPushButton , QToolButton , QCheckBox , and QRadioButton ) can display both text and icons . The problem is when I modify the image inside the Qlabel the update of image works bad. 1) QSignalMapper maps a QObject* sender to a (int, string, QWidget* or QObject*). QtCore. QSignalMapper类的功能核心是要建立一个从原始信号的object到需要的数据的映射（setMapper函数）。. This is an overloaded function. map ()作为. QSignalMapper classes support SetMapping function to a particular integer or string, and associate a particular object. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. But the compiler complains about no matching parameters. How can I do that?, in the code I present it receives the. Updating class variable Qt signals and slots. The only function that we need to implement is the constructor: A list of texts is passed to the constructor. Note that QSignalMapper is a very old class that was required when it wasn't possible to use lambdas in Qt slots. The use of QSignalMapper is not necessary in Qt 5, and is optional in Qt 4. You shouldn't need to use QSignalMapper with QDialogButtonBox. You could simply assign a value to the button with a map ( QMap, std::map) or through a. Widgets are grouped into classes according to their function. . These functions can be used to implement blocking serial ports: waitForReadyRead () blocks calls until new data is available for reading. I have followed the answer by X. Learn more about TeamsQSignalMapper:: QSignalMapper (QObject *parent = nullptr) Constructs a QSignalMapper with parent parent. Unfortunately, all attempts of making this used QSignalMapper successfully in a similar situation. QSignalMapper类可以看成是信号的翻译和转发器。 它可以把一个无参的信号翻译成带int参数、QString参数、 QObject* 参数或者QWidget *参数的信号，并将之转发。 QSignalMapper类的功能核心是要建立一个从原始信号的object到需要的数据的映射（setMapper函数）。 Much cleaner code and it’s easier to maintain and modify. – Detailed Description. plist file in the application’s bundle (See Qt for macOS - Deployment ). toString (); QSignalMapper * signalMapper = new QSignalMapper (parent); //this is just one of many trials to get this working, i hope you get the picture connect (combo , SIGNAL (activated (int. So you can have one like: QSignalMapper * mapper = new QSignalMapper(this); QObject::connect(mapper,SIGNAL(mapped(QWidget *)),this,SLOT(mySlot(QWidget *))); The QSignalMapper class bundles signals from identifiable senders. Try this instead:( 2 ) 使用QSignalMapper类. QSignalMapper类内置了一个Map表，将Singnal和参数对应起来，然后多个信号关联到Mapper上，由mapper负责管理，并且mapper关联到槽函数中，将对应的参数传入槽函数 The code below shows my attempt to get several movable VerticalLineSegment objects (derived from QGraphicsLineItem and QObject) to signal one (using a QSignalMapper) another when they move. I got following qt message. The object's mapped widget is passed in widget. because you wrote it in your first answer to this post. The mentioned message was logged only one time. 8, which signals and slots system was based on the use of macros. We strongly advise against using it in new code. @. qml I have the following signals:. ** ** Contact info@trolltech. The above diagram shows such a composite widget that. A collection of tutorials with walkthrough guides are provided with Qt for Python to help new users get started. Hope you found it useful. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. I'd appreciate help as to why the VerticalLineSegment slot updateX is not triggered. private: QSignalMapper *signalMapper; private slots: void buttonGeneric (QPushButton &button); signals: void clicked. Parameters: arg__1 – int. clear () where LineEdits is your list of widgets. Simply use a QMap<QObject*,ValueStruct>, where ValueStruct keeps your arguments. Damn! So I did, I was guessing at that point! :( Now I know better, from the SO link I gave you :). This is useful when multiple objects need to send a signal to the same slot, but with different parameters. 2. } Ignoring the “captured variables” part for now, here is a simple lambda which increments. QSignalMapper is the best solution to connect multiple signals to the same slot. Adds a mapping so that when map () is signaled from the given sender, the signal mapper ( identifier) is emitted. QtCore. CPP < /代码>中分配和删除。. QSignalMapper extracted from open source projects. The positioning of the content within the. To start viewing messages, select the forum that you want to visit from the selection below. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. This is what I have so far: chess. The QSignalMapper class bundles signals from identifiable senders. I want to create a common handler of editingFinished() or textChanged() signal and assign it to all the QLineEdits. The QSignalMapper class bundles signals from identifiable senders. When this loop is done, processEvents will be called again and in that the doSomething () will be executed. You can check the return bool and have a look to the output window of your application. I have a QTreeWidget in which each of its items has a QComboBox in a column. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. This signal is emitted when map () is signalled from an object that has an integer mapping set. I've written a function called addTab(. Adds a mapping so that when map () is signaled from the given sender, the signal mapper ( identifier) is emitted. A QSignalMapper object is one that emits a mapped() signal whenever its map() slot is called. All UI elements that Qt provides are either subclasses of QWidget , or are used in connection with a QWidget subclass. Qt Library. @jaouad100 said in How to solve Object::connect: No such signal: void setImage (const QImage &); Make this method as slot: protected slots: void setImage(const QImage &) ; (Z (:^. With separate slots, class signature change needed. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal.