Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interestingQt Signal mapper and sending QLabel by reference and OpenCv 2. My ui object is UI. 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. Qt Quick TableViews examples - Pixelator. I implemented setData in my table model, so editing is working (I can change the data in the cell, setData is called to update the model, and the table is properly updated). In this way the slot associated to the signal mapper is invoked only when the checkbox is checked and not when it is unchecked. The connection is established as follows: 1. 15. E. 15. Only users with topic management privileges can see it. . QSignalMapper. 8. Finally we connect the signal mapper's mappedString() signal to the. Signal Types. Go to Qt Creator Project settings and check the all ABIs like my screenshot. Model/View is a technology used to separate data from views in widgets that handle data sets. RamzyKaram92 last edited by . Please let me know!A vertical model mapper is used to create a connection between a line, spline, or scatter series and the data model that has X and Y columns for the coordinates and holds the data points for the XYSeries as rows. code an addDestinationSlot method that takes a QString/slot pair and maps the string to the slot. The only function that we need to implement is the constructor: A list of texts is passed to the constructor. Introduction []. The object's mapped widget is passed in widget. So in this function, you can add your code to change the page of stackedwidget corresponding to the action produced by currentactivewidget. Constructs a QSignalMapper with parent parent. qt_core 0. In the Combo Widget Mapper Example, we showed how to use a named mapping between a widget mapper and a QComboBox widget with a special purpose model to relate values in the model to a list of. How can I do that?, in the code I present it receives the. 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. It's possible to find out which object emitted a signal by calling sender() inside the slot, but I don't think that's good practice. Only users with topic management privileges can see it. A list of texts is passed to the constructor. Hey there, is there a way to be notified when a QPalette's value gets changed ? like a signal or something ? I'd like to update a QPixmap accordingly to QPalette's color dynamically. See also setMapping(). There are 4 types of Signals included. 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. Create a signal mapper: signalMapper = QSignalMapper () Associate a mapping of type int with the callback function: signalMapper. The class supports the mapping of particular strings or integers with particular objects using setMapping(). Every time the current index changes, each widget is updated with data from the model via the property specified when its mapping was made. View Profile View Forum Posts View Articles Intermediate user Join Date Sep 2007 Location Rome, GA Posts 199 Thanks 14 Thanked 41 Times in 35 Posts Qt products PlatformsThe QSignalMapper class is very useful, for example, in situations were you have a couple of QPushButtons and you want to connect the clicked-signal of each button to a single slot and still be able to identify the sender. Consider a card game. ©2013 Digia Plc and/or its subsidiaries. This class collects a set of parameterless signals, and re-emits them with integer or string parameters corresponding to the object that sent the signal. The QSignalMapper class bundles signals from identifiable senders. The QSignalMapper class bundles signals from identifiable senders. In this example, the QSignalMapper object is created and connected to the clicked () signal of two buttons. It's more about the design. Since then, Qt5 has been released and C++11 is now A Thing. So, I added my own SLOT(doThings(int)). Only users with topic management privileges can see it. Since then, Qt5 has been released and C++11 is now A Thing. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters. Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interestingI created a QSlider *x_slider[8] array and now I want to create a connect to a slot like this,. You can trigger behaviors in response to user input, such as button presses or text input, or events in your own code. On __enter__ the signals of the given object are blocked and on __exit__ the blocked state is set to the previous state. In the Combo Widget Mapper Example, we showed how to use a named mapping between a widget mapper and a QComboBox widget with a special purpose model to relate values in the model to a list of choices. But you can do a loop over the list to connect all elements individually. Now i want to map all of them in a signal mapper. The class supports the mapping of particular strings or integers with particular objects using setMapping(). On the #pyqt channel on Freenode, lauri asked about connecting identically-named signals with different parameters from QSignalMapper to slots. Can you describe the workflow of that functionality ? e. The example above can be rewritten simpler without QSignalMapper by connecting to a lambda function. At least, that is the safest way to do a cast. g. 1) QSignalMapper maps a QObject* sender to a (int, string, QWidget* or QObject*). But, this example code from 4. See also setMapping(). Forum: Qt Programming. . This topic has been deleted. Main Page; Packages; Classes; Class List; Class Index; Class Hierarchy; Class MembersThe signals and slots mechanism is type safe: The signature of a signal must match the signature of the receiving slot. It behaves essentially like the above function. The object's mapped widget is passed in. Detailed Description¶. This topic has been deleted. See also setMapping(). // Create QSignalMapper object and connect its mapped signal to a slot QSignalMapper* signalMapper = new QSignalMapper. ) Since the signatures are compatible, the compiler can help us detect type mismatches. More. connect (signalMapper. RamzyKaram92 last edited by . However, the Python multiprocessing library requires. We connect each button’s clicked() signal to the signal mapper’s map() slot, and create a mapping in the signal mapper from each button to the button’s text. Use a signal that looks like: @ signals: void newPixmapReady(const QPixmap& pixmap); @ If you don't want to lock your GUI thread, you can get some inspiration from the Mandelbrot example yeah, because i'll destroy it when it opens cause it have a button to ask me if i agree on the values, and when i press confirm, it will close)) but i'm sorry, i guess i've another issue with the Timer ?! and the SignalMapper parameters ?! Example 1: In this example, we have multiple buttons (btn1, btn2, and btn3) and we want to connect them all to a single slot. See also setMapping(). 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. Constructs a QSignalMapper with parent parent. Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interesting1 Answer. This is done automatically when mapped objects are destroyed. Finally we connect the signal mapper’s mappedString(). Also the fact that i was using SubMenu as argument to setMapping , where as MenuAction item should have been used instead. MainWindow::MainWindow (QWidget *parent) : QDialog (parent), ui (new. removeItem method rather than providing the subsystem an address to connect the function. . This signal is emitted when map() is signaled from an object that has a string mapping set. QtCore. 1. You can rate examples to help us improve the quality of examples. yeah, because i'll destroy it when it opens cause it have a button to ask me if i agree on the values, and when i press confirm, it will close)) but i'm sorry, i guess i've another issue with the Timer ?! and the SignalMapper parameters ?! hi, this is my code to display a QComboBox in a QTableWidget and using QSignalMapper to re-emit the signal but the output is Object::connect: No such signal QComboBox::currentIndexChanged () Qt Code: Switch view. The call to setMapping () inside the for loop establishes a mapping between a button and an integervalue; for example. It is subclassed from QPushButton and also it holds a private member:private:. This class can tell the outside world that its state has changed by emitting a signal, valueChanged(), and it has a slot which other objects can send signals to. These are the top rated real world Python examples of PyQt5. Have a look at QSignalMapper's documen. This function was introduced in Qt 5. Ask Question Asked 7 years, 7 months ago. This signal is emitted when map() is signaled from an object that has a string mapping set. Update 2: It worked after the correction suggested in the solution below for QSignalMapper. io The QSignalMapper class bundles signals from identifiable senders. But you can do a loop over the list to connect all elements individually. But, this example code from 4. This signal is emitted when map() is signaled from an object that has a string mapping set. MainWindow::MainWindow (QWidget *parent) : QDialog (parent), ui (new Ui::MainWindow) { ui. Frequently Used Methods. Since your "load" and "return to main menu" signals are being sent from the same sender object they will be mapped the same way. This is an overloaded function. Share. It behaves essentially like the above function. The signals and slots mechanism is a central feature of Qt and probably the part that differs most from the features provided by other frameworks. Slot Apps for Real Money. This slot emits signals based on the sender object. Cards are drawn from a deck and displayed on screen. I have three classes, that need to cooperate. What is the function of signal mapper? A signal mapper is constructed and for each text in the list a QPushButton is created. A signal mapper is constructed and for each text in the list a QPushButton is created. A signal mapper is constructed and for each text in the list a QPushButton is created. I have used the example code below. This topic has been deleted. In this way the slot associated to the signal mapper is invoked only when the checkbox is checked and not when it is unchecked. 1 Answer Sorted by: 1 The original example code (which I wrote), works perfectly fine for me using either Python2 or Python3 with several different recent. void DMXTable ::SLOT_AllDMXPropsReceived( unsigned long u4member, void* pData ) {. The class supports the mapping of particular strings or integers with particular objects using setMapping(). . Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interestingA vertical model mapper is used to create a connection between a data model and QPieSeries, so that each row in the data model defines a pie slice and each column maps to the label or the value of the pie slice. In this article weexplore various solutions, including the use of QSignalMapper. This can be achieved using QSignalMapper. Looks like all good. connect (self. thanks SGaist, you understood very well, and Binary Image Class has alot of roles to do, alot of caluclations and anding operation between filtered images, i'll try to look at the QInputDialog. QtCore. A list of texts is passed to the constructor. The setMapping function assigns a unique integer value (1 and 2) to each button. SIGNAL ("clicked (int)")) Having self. removeItem, QtCore. Qt Signal mapper and sending QLabel by reference and OpenCv 2. This class was mostly useful before lambda functions could be used as slots. The class supports the mapping of particular strings or integers with particular objects using setMapping(). if you call. Qt Code: Switch view. 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. We connect each button's clicked() signal to the signal mapper's map() slot, and create a mapping in the signal mapper from each button to the button's text. map) mapper. The QDataWidgetMapper class makes it easy to relate information from a model to widgets in a user interface. 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. Anyway, one of the thing is that you are mapping the mapper to the widget which is not the way it's supposed to work. . Qt Library. ) in a loop. Setting up a view to display the items in the model is simply a matter of calling its setModel() function with the directory model as the argument. Adds a mapping so that when map () is signaled from the given sender, the signal mapper ( identifier) is emitted. RamzyKaram92 last edited by . Anyway, one of the thing is that you are mapping the mapper to the widget which is not the way it's supposed to work. [signal] void QSignalMapper:: mappedWidget (QWidget *widget) This signal is emitted when map() is signalled from an object that has a widget mapping set. On running the application, we can click the button to execute the action (slot). void QSignalMapper::removeMappings ( const QObject * sender )void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. The optional named argument name defines the signal name. This signal is emitted when map() is signaled from an object that has a string mapping set. [signal] void QSignalMapper:: mappedWidget (QWidget *widget) This signal is emitted when map() is signalled from an object that has a widget mapping set. The signals and slots mechanism is a central feature of Qt and probably the part that differs most from the features provided by other frameworks. This signal is emitted when map() is signaled from an object that has a string mapping set. I have used the example code below. void QSignalMapper:: setMapping (QObject *sender, QObject *object) Adds a mapping so that when map () is signalled from the sender , the signal mappedObject ( object ) is emitted. Specify the first and last column numbers for the span of columns you want to insert into an item in a model. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. You can then use QObject::sender () within the slot to determine which object emitted a signal. Qt Signal mapper and sending QLabel by reference and OpenCv 2. Enjoy all the popular free blackjack games right here, with no sign up and no download needed. Header: #include <QSignalMapper> CMake: find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core) qmake: QT += core: Inherits: QObject: List of all members, including inherited members;Qt Quick TableView examples - Conway’s Game of Life. 20. 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. void QTableWidget:: setCellWidget ( int row, int column, QWidget * widget) Sets the given widget to be displayed in the cell in the given row and column, passing the ownership of the widget to the table. 5) 4. ) summary refs log tree commit diff statsFelgo Services App Development Mobile and desktop application development Embedded Development Applications and companion apps for embedded Qt Consulting and. A vertical model mapper is used to create a connection between a line, spline, or scatter series and the data model that has X and Y columns for the coordinates and holds the data points for the XYSeries as rows. [signal] void QSignalMapper:: mapped (QWidget *widget) This function is obsolete. QChart*chart =newQChart; chart->setAnimationOptions(QChart::AllAnimations); The first line of the code below creates new bar series. This function was introduced in Qt 5. Signal is the base implementation of the Signal and can be created on a per instance level. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. Tango technology creates a top-down floor plan in real-time while you analyze Wi-Fi signals on the move. A signal mapper is constructed and for each text in the list a QPushButton is created. Qt Base (Core, Gui, Widgets, Network,. 2. This topic has been deleted. Or just change On_clicked into slot and connect signal mapped (int) to it (use SLOT keyword then). A section is a column of a model if the orientation is horizontal (the default), otherwise a row. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. Use a signal that looks like: @ signals: void newPixmapReady(const QPixmap& pixmap); @ If you don't want to lock your GUI thread, you can get some inspiration from the Mandelbrot exampleThe QSignalMapper class is provided for situations where many signals are connected to the same slot and the slot needs to handle each signal differently. Header: #include <QSignalMapper> CMake: find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core) qmake: QT += core: Inherits: QObject: List of all members, including inherited members;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. A slightly better way would be to provide a numbering. I have used the example code below. Model mappers enable using a data model derived from the QAbstractItemModel class as a data source for a chart. 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. Sometimes, however, we would like the slot to behave slightlydifferently depending on which widget invoked it. The only function that we need to implement is the constructor: SIGNAL (clicked ()) SLOT (map ())); signalMapper. ; ClassSignal is an object that can be created as a class variable and will act like a signal. The signals and slots mechanism is a. We connect each button's clicked() signal to the signal mapper's map() slot, and create a mapping in the signal mapper from each button to the button's text. A signal mapper is constructed and for each text in the list a QPushButton is created. Only users with topic management privileges can see it. Detailed Description. You cannot connect a whole list at once. void QSignalMapper::mapped ( int i) [signal] This signal is emitted when map() is signalled from an object that has an integer mapping set. First, motivQSignal mapper /** 2 ** 3 ** Copyright (C) 2016 The Qt Company Ltd. Signal/Slot while model inserts and removes rows in QTableView dynamically. Qt Signal mapper and sending QLabel by reference and OpenCv 2. Qt allows us to connect multiple signals to the samesignal or slot. Finally we connect the signal mapper's mappedString() signal to the. Just running the program no. Hello friends, I am using multiple QPushButtons in my project. a recipe for catastrophe and maintenance nightmare. Every user-defined dialog, main window or widget that is loaded by the python-class ui or that is loaded from a plugin, contains one instance of this class. The QSignalMapper class bundles signals from identifiable senders. Only users with topic management privileges can see it. If cell widget A is replaced with cell widget B, cell widget A will be deleted. QSignalMapper extracted from open source projects. But signal mapper doesn't send any signal to the slot. SIGNAL ("mapped (int)"), self. Any model derived from QAbstractItemModel can be used as the source of. Namely, I am writing language change aware app and I coded a class, derived from QPushButton, which represent a "nation flag button". Alternatively with C++11 and up, you can use a lambda to extend your connection with a pointer to the sender. Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interestingSignal Types. @ void NewValues::on_btnStart_clicked() { BinaryImage mBinaryImage; mBinaryImage. But, this example code from 4. e. also i forgot to mention that somebody from another site told me "Use @QSignalMapper::setMapping(QObject *sender, QWidget *widget) @ and @ QSignalMapper::mapped(QWidget *widget) @ signal, then cast it to @QLabel@ by using @qobject_cast@ " i think that thi. R. You can invoke a slot with QMetaObject::invokeMethod. 4351. Qt Signal mapper and sending QLabel by reference and OpenCv 2. An overview of Qt's signals and slots inter-object communication mechanism. More. Show Hide. connect (self. Header: #include <QSignalMapper> qmake: QT += core Inherits: QObject. We connect each button's clicked() signal to the signal mapper's map() slot, and create a mapping in the signal mapper from each button to the button's text. void QSignalMapper::mapped ( int i) [signal] This signal is emitted when map() is signalled from an object that has an integer mapping set. removeItem () in the connect method will actually try to call the self. Qt Signal mapper and sending QLabel by reference and OpenCv 2. Using a QSignalMapper for that task is just an overkill. void QSignalMapper::removeMappings ( QObject * sender) Removes all mappings for sender. 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上做处理。有的朋友会问了，为什么要这么麻烦，需要转一手，不能去掉中间的QSignalMapper，而直接调用吗。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. General and Desktop. Forums; Tutoriels; Magazine; FAQs; Blogs; Projets; Chat; Newsletter; Accueil Actualités IT Pro Conception Cycle de vie du logiciel ConceptionForums; Tutoriels; Magazine; FAQs; Blogs; Projets; Chat; Newsletter; Accueil Actualités IT Pro Conception Cycle de vie du logiciel ConceptionMapper = new QSignalMapper( this ); connect( mapper, SIGNAL(mapped(QWidget. 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 list of texts is passed to the constructor. So you can have one like: QSignalMapper * mapper = new QSignalMapper(this); QObject::connect(mapper,SIGNAL(mapped(QWidget *)),this,SLOT(mySlot(QWidget *))); See full list on doc. The object's mapped widget is passed in widget. Online Casinos Reviews. 15. Finally, the mapped () signal of the QSignalMapper is connected to a slot, which handles the button press by passing the integer value as a parameter. QSignalMapper类可以看成是信号的翻译和转发器。. Go to Qt Creator Project settings and check the all ABIs like my screenshot. Your timer should be connected to that slot that does the processing, then from this slot emit a signal with the QPixmapThe documentation (Qt 5 latest version) of QThread, you'll see the various implementation possibilities. Re: Passing a pointer in Signal/Slot Connection. Keep the image processing in BinaryImage and emit the QPixmap when ready. Lets say they are named pushbutton1, pushbutton2, etc. . See also setMapping(). Then comes the interesting part with the signal mapper: the series of setMapping() calls sets the mapper up so that each signal from one of the buttons will result in a QSignalMapper::mapped() signal, with the given. 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. RamzyKaram92 last edited by . , you will call the same slot multiple times with single signal. A slot is any callable function or method. Several years ago I wrote a short piece on QSignalMapper to give a quick example of how it can be used. Use mapped (QWidget*) and change your slot to have the same signature: button_pushed (QWidget*). In this article, we will explore the mechanisms powering the Qt queued connections. Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interestingQt Signal mapper and sending QLabel by reference and OpenCv 2. Where GPS is unavailable, the Anritsu MA8100A Series solution delivers real-time 3D location. But, this example code from 4. Qt Signal mapper and sending QLabel by reference and OpenCv 2. Header: #include <QSignalMapper> qmake: QT += core Inherits: QObject. Hello friends, I am using multiple QPushButtons in my project. Then you connect your signal mapper to the custom signal checkBoxChecked, instead of the standard toggle (bool) signal. A list of texts is passed to the constructor. connect (sync_checkboxes) Connect the widgets triggering the signals to the mapper: checkbox_1. 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. __init__ (self, QObject parent = None)The parent argument, if not None, causes self to be owned by Qt instead of PyQt. Now inside of readCombo i want to read a string and pass it to change picture: QString imageFileName = xmlreader->attributes (). Note that in mostI have been trying to implement signal mapper. 8 doesn't have SLOT getting signal from 'mapped'. This function was introduced in Qt 5. This topic has been deleted. RamzyKaram92 last edited by . Hi, I have a slot that I'd like to connect to. It behaves essentially like the above function. connect. This signal is emitted when map() is signaled from an object that has a string mapping set. waitForUser(ui->lblNewValues); // Show the user the values he collected // this here is a memory eater since you never destroy it (it will be at program's end but until t. This topic has been deleted. QSignalMapper is a class in Qt library that is used to map multiple signals to a single slot. Python QSignalMapper - 59 examples found. [signal] void QSignalMapper:: mappedWidget (QWidget *widget) This signal is emitted when map() is signalled from an object that has a widget mapping set. For example, as shown in the diagram, we insert three columns before column 4, so first is 4 and last is 6: beginInsertColumns(parent,4,6); This inserts the three new columns as columns 4, 5, and 6. This function was introduced in Qt 5. The QSignalMapper class bundles signals from identifiable senders. Signal/Slot while model inserts and removes rows in QTableView dynamically. clicked [ ()]. QSignalMapper. 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. Qt Library. void QSignalMapper::setMapping ( QObject * sender, int id) Adds a mapping so that when map() is signalled from the given sender, the signal mapped(id) is emitted. 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. Then my earlier suggestions still stand. See also setMapping(). 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. If I got it right, you just want to unmap a button as soon as it was clicked and corresponding client was disconnected. Hello Everybody, this is my first post, so i hope that i won't mess with the rules, also a small note, i'm a newbie in Qt, just one month old, it is very interestingthanks SGaist, you understood very well, and Binary Image Class has alot of roles to do, alot of caluclations and anding operation between filtered images, i'll try to look at the QInputDialog. 15. __init__ (self, QObject parent = None)The parent argument, if not None, causes self to be owned by Qt instead of PyQt. An instance of PythonQtSignalTarget is created as virtual slot for the corresponding python method 2. You can't execute code inside SLOT (). This signal is emitted when map() is signaled from an object that has a string mapping set. Hope you found it useful. This is useful for QML applications which may refer to the emitted values by name. Much cleaner code and it’s easier to maintain and modify. But we also want to know which button triggered the signal. It's more about the design. void QSignalMapper::removeMappings ( const QObject * sender )The QSignalMapper class bundles signals from identifiable senders. map) checkbox_2. QSignalMapper(QObject *parent = nullptr) virtual ~QSignalMapper()void. Only users with topic management privileges can see it. Any help would be really appreciated. The QSignalMapper class bundles signals from identifiable senders. mappedObject (QObject * object) void. This enum value can be used to set custom label text per-point. I didn't suggest to make QPixmap the return type of anything. Member Function DocumentationForums; Tutoriels; Magazine; FAQs; Blogs; Projets; Chat; Newsletter; Accueil Actualités IT Pro Conception Cycle de vie du logiciel ConceptionQyoto is a C# language binding for Qt. The QSignalMapper class bundles signals from identifiable senders. It behaves essentially like the above function. So i am using QSignalMapper. void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. you really can't connect to a private slot of a QObject; You are creating a new signal mapper every time you call readCombo which you aren't clearing - resulting memleaks. Qt Signal mapper and sending QLabel by reference and OpenCv 2. It doesn't work this way. Note that in mostI have been trying to implement signal mapper. It throws "F libc : Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x2787c in tid. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters. The class supports the mapping of particular strings or integers with particular objects using setMapping(). RamzyKaram92 last edited by . But we also want to know which button triggered the signal. QSignalMapper. See also setMapping(). Re: Passing a pointer in Signal/Slot Connection. see documentation: 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.