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 reason why your QSignalMapper code doesn't work is probably because you are connecting to the wrong overload of the mapped 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. mappedInt(arg__1) #. Update. Try this instead:( 2 ) 使用QSignalMapper类. I have. I need to implement a simple message bus: One process only thus no need do D-Bus. The QSignalMapper class bundles signals from identifiable senders. But is there a way to use a QStringList? The idea would be. There's aleady a built-in dock-widget menu. You could simply assign a value to the button with a map ( QMap, std::map) or through a. You shouldn't need to use QSignalMapper with QDialogButtonBox. 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。. ) is supported. Additionally, double check that your connects are being made by. If nothing is passed, the new signal will have the same name as the variable that it is being assigned to. If you want to have the signal clicked (int, int) in a button, you can subclass. @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 (:^. map ()作为. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters. I'd appreciate help as to why the VerticalLineSegment slot updateX is not triggered. The object's mapped widget is passed in widget. QSignalMapper. The string-based syntax can connect C++ objects to QML objects, but the functor-based syntax cannot. Please check the attached snapshot. Related questions. 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. However, beside that id it is not possible to extract console pointer,. size (); ++i) { ButtonsMapper->setMapping (Buttons [i], i); } } its good if i have 1 QList, but i have at least 8 QList that i supposed to delete. 3. " GitHub is where people build software. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters. This class collects a set of parameterless signals, and re-emits them with integer, string. 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,. I have a question about QSignalMapper. There is a problem in the connection since the compiler cannot understand it since there are signal and slots overloads. 2. 15. As such, QSignalMapper is not deisgned to transfer parameters into other slots for you. I would like to select file via file dialog and upload board with selected file by upload button. It behaves essentially like the above function. Sorted by: 1. activeDocument(). 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. 3. 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. Just do the same. . The Camera Example demonstrates how you can use Qt Multimedia to implement some basic Camera functionality to take still images and record video clips with audio. Description: A cross-platform application and UI framework (mingw-w64) Group(s): mingw-w64-x86_64-qt6 Repo: mingw64 Homepage: existing slots are not recognized. An exclusive button group switches off all checkable (toggle) buttons except the one that. The QWidget class provides the basic capability to render to the screen, and to handle user input events. 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）。. The following pages provide more information about Qt’s core features: The Meta-Object System. It is provided to keep old source code working. Create a signal mapper: signalMapper = QSignalMapper () Associate a mapping of type int with the callback function: signalMapper. . 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. 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 strongly advise against using it in. The object's mapped widget is passed in widget. See this question for three ways of mapping one of a multitude of objects to a value. 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. Here an example of what I need: (Note the slots) void MainWindow::HttpRequest (const QString & URL, QCustomWidget *Feed) { manager = new QNetworkAccessManager (this); reply = manager->get (QNetworkRequest (QUrl (URL))); connect (reply. Instead of individually creating each QPushButton in qtcreator & qtdesigner, and individually creating each on_clicked signal function for each button, I am trying to apply a QSignalMapper. QSignalMapper is not about sending arguments from signals to slots but to let signal receiver know "who" was that or what data use. QSignalMapper is a class in Qt library that is used to map multiple signals to a single slot. 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. Returns the meta-method index of the signal that called the currently executing slot, which is a member of the class returned by sender (). So when you have many items you can QSignalMapper or try something like next (there are many ways to do this, I give example with small code): QList<QPair<QCheckBox*,QGraphicsItem*> > pair; //fill your list with all QCheckBox. 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）。. 3 Answers. It also lets you associate ints, QWidgets, and QObjects to a QAction. connect (sync_checkboxes) Connect the widgets triggering the signals to the mapper: checkbox_1. h" #endif // QT_H #ifndef QT_NO_SIGNALMAPPER class QSignalMapperData; struct QSignalMapperRec; class Q_EXPORT QSignalMapper : public QObject {. QListWidget uses an internal model to manage each QListWidgetItem in the list. C++ compilation compression computer vision css drag selection example game engine games Guild Wars 2 GW2 html image processing images Info. I have read a lot of theory about QSignalMapper,Welcome to the MadMapper Tutorial Series!THE PROJECTOR I USED: Link: Answer. Here is my code for the SignalMapper: In my header:. Algunos amigos pueden preguntar, ¿por qué es tan problemático y. The application name is fetched from the Info. When the content is changed using any of these functions, any previous content is cleared. The positioning of the content within the. 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. This function is typically used together with construct () to perform low-level management of the memory used by a type. Hope you found it useful. I have 4 QLineEdits and 4 QPushButtons. Viewed 82 times 0 I'm making an application which will be able to program my board. Ask Question Asked 8 years, 2 months ago. Since your "load" and "return to main menu" signals are being sent from the same sender object they will be mapped the same way. Use the setMapping method to add a mapping between a sender. Calling QComboBox* combo = (QComboBox* )sender() in the slot fails, presumably because sender() is now the QSignalMapper. and I assume you initialized the "signalMapper = new QSignalMapper (this)" in the MyApp constructor. Related questions. 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. There is a problem in the connection since the compiler cannot understand it since there are signal and slots overloads. __init__ (self, QObject parent = None)The parent argument, if not None, causes self to be owned by Qt instead of PyQt. Simply use a QMap<QObject*,ValueStruct>, where ValueStruct keeps your arguments. keyboard. These are the top rated real world Python examples of PyQt5. The QSignalMapper is used to re-emit signals with optional parameters. 0. 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. Obviously it´s caused by Esri: QObject::connect: No such signal QRTImpl::TaskHelper::taskCompleted (QUuid,. The cards are clickable, and lead to the same effect, so the use of QSignalMapper was obvious. 2 [Русский] Qt Core ; QSignalMapper Class 8. Eliminate QSignalMapper entirely and connect the button's clicked signal to mySlot. QtCore. –The trade-off with QSignalMapper is that you gain information about the source of the signal, but you lose the original arguments. Already with Qt4, you can use QSignalMapper to achieve much the same effect, with a few more objects. map) Tonight's PyQt snapshot will be smarter about finding a usable Qt slot before deciding that it needs to. snap1. QSignalMapper 是一个将已知发射对象和信号绑定在一起的类。. I was wondering if that was possible. – jonspaceharper But this removes all knowledge of the original sender widget. J. 1. By default, labels display left-aligned, vertically-centered text and images, where any tabs in the text to be displayed are automatically expanded. A signal mapper is constructed and for each text in the list a QPushButton is created. For any interested, I worked around the problem using a closure, which seems a bit cleaner from a coding point of view, although I don't have any idea if it is more efficient or not: I'm trying to use QSignalMapper with my buttons, but I can't seem to get it to work to trigger my slot. When a widget is used as a container to group a number of child widgets, it is known as a composite widget. 1. } Ignoring the “captured variables” part for now, here is a simple lambda which increments. 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?I think in this case QSignalMapper is the way to go. @. 1. You can only use the signals that exist in QSignalMapper. I have simple application, a calculator. cpp file. @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. These are the top rated real world Python examples of PySide. private: QSignalMapper *mapper; In my cpp: //Constructor: mapper = new QSignalMapper (this); //Init function, called by the constructor connect (mapper, SIGNAL (mapped (int)), this,. Qt provides four classes for handling image data: QImage, QPixmap, QBitmap and QPicture. Fix:All of the button's clicked signals will call the same function, passing to the function the associated QPushButton. I’ve since found another couple of places in my code that benefit from QSignalMapper since it handles more than QString. ** ** ** ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). I think you can use this method: [protected] int QObject:: senderSignalIndex () const. Qt reports if the signal and slot cannot be connected. This is useful for QML applications which may refer to the emitted values by name. Signal (such as the clicked button) may be connected to the. If it is the case, QSignalMapper cannot help you here. PyQT: adding to QAbstractItemModel using a button. Map Viewer Example#. 15. trigger () behaves correctly, and not act_str. On the #pyqt channel on Freenode, lauri asked about connecting identically-named signals with different parameters from QSignalMapper to slots. QProgressBar { border: 2px solid grey; border-radius: 5px; } QProgressBar::chunk { background-color: #05B8CC; width: 20px; } This leaves the text-align , which we customize by positioning the text in the center of the progress bar. Hope you found it useful. – SPlatten. addObject("Part::Box", "myBox") s = box. QSignalMapper *mapper = new QSignalMapper. PySide6. Theoretically, you could keep a pointer to the signal mapper around, and remap the indexes after deletion. Before Qt 5. It is a clean and pretty solution, I agree, but nobody mentions that lambda creates a closure, which holds a reference - thus the. The central feature in this model is a very powerful mechanism for seamless object communication called signals and slots. The workaround is to explicitly specify a signal that is compatible with map (). This class collects a set of parameterless signals, and re-emits them with integer or string parameters. It does not provide a visual representation of this container (see QGroupBox for a container widget), but instead manages the states of each of the buttons in the group. 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. Creating custom widgets is done by subclassing QWidget or a suitable subclass and reimplementing the virtual event. 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. 我现在有一个QML对象<代码>键盘。. 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. _mapper =. By voting up you can indicate which examples are most useful and appropriate. The class supports the mapping of particular strings or integers with particular objects using setMapping (). Using Maintenance Tool #. These functions can be used to implement blocking serial ports: waitForReadyRead () blocks calls until new data is available for reading. And: Great! The feature I was looking for pretty much built-in! This sure seems less complex than using QSignalMapper and can potentially execute a number of actions with a single Signal-Slot connection, of course, depending on the property type and its 'interpretation' by the Slot. When trying to add a derived QWizardPage with a custom Q_PROPERTY in the constructor of a derived QWizard I get the following runtime warning for my minimal example: QObject::connect: Attempt to. 1 Answer. It is provided to keep old source code working. Press Ctrl+a / Ctrl+b to switch between tabs. I shortened the code to be more precise but this has hidden the actual cause. It's actually a problem with QSignalMapper. ** Contact: ** ** This file is part of the QtCore module of the. 2. The Map Viewer example shows how to display and interact with a map, search for an address, and find driving directions. The syntax of a lambda expression is the following: [captured variables] (arguments) {. QSignalMapper * mapper = new QSignalMapper (this);. ecloud ecloud. QSignalMapper. Just right-click any dock title-bar, or any tool-bar or menu-bar. With separate slots, class signature change needed. 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. [signal] void QSignalMapper:: mapped (const QString &text) This function is obsolete. plist file in the application’s bundle (See Qt for macOS - Deployment ). 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. Note that in most cases you can use lambdas for passing custom parameters to slots. It also lets you associate ints, QWidgets, and QObjects to a QAction. Each of the above functions has a blocking variant that returns the final result instead of a. With QSignalMapper, trivial change in a . Python QSignalMapper - 59 примеров найдено. Consider a card game. private: QSignalMapper *mapper; In my cpp: //Constructor: mapper = new QSignalMapper (this); //Init function, called by the constructor connect (mapper, SIGNAL (mapped (int)), this, SLOT. This class collects a set of signals without parameter, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal. The QSignalMapper class bundles signals from identifiable senders. For example, we change the border to grey and the chunk to cerulean. It's not broken :) If you click twice in quick succession the events you get are: QEvent::MouseButtonPress QEvent::MouseButtonRelease QEvent::MouseButtonDblClick QEvent::MouseButtonRelease. I am currently trying to complete a project using Qt4 and C++. 上面的写法是非常繁琐的，Qt提供了一个类QSignalMapper，用于信号分发，类似于信号中转站：. ) Since the signatures are compatible, the compiler can help us detect type mismatches. . 15. For a description of simple non-hierarchical list and table models, see the Model/View Programming overview. Using button and objects in pyqt. 然后可以将. This function was introduced in Qt 5. The class supports the mapping of particular strings or integers with particular objects using setMapping(). 应用场景一般是 ：有一些信号，发送的参数. Widgets can be added to menus by using instances of the QWidgetAction class to hold them. Each tab has a tabText(), an optional tabIcon(), an optional tabToolTip(), optional tabWhatsThis() and optional tabData(). While it still exists, it's rarely used, and is mostly considered obsolete. So far we've created a window and added a simple push button widget to it,. fix deprecated warning int QWheelEvent::delta() break macOS build (Page 1) — Code — QElectroTech —The QSignalMapper class bundles signals from identifiable senders. I can't get the signal mapped (QObject*) to trigger. The use of QSignalMapper is not necessary in Qt 5, and is optional in Qt 4. We are using plugins in our application and different plugins are responsible for different types of objects. For more information about how to use Maintenance Tool with the command line interface, see Get and Install Qt with. 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. See also setMapping(). The signals and slots mechanism is type safe: The signature of a signal must match the signature of the receiving slot. Suppose you have three push buttons that determine which file you will open: "Tax File", "Accounts File", or "Report File". cpp. This action should be placed where the “About” menu item is in the application menu. As finmor suggests, you should look at. Toggle table of contents sidebar. 3 Qt: the signal handler is not called when the signal is emitted. This is an overloaded function. QtCore. Share. But in Qt4, receiver must still always be a QObject. takeAt (i)); for (int i = 0; i < Buttons. # # Each signal is associated in the QSignalMapper with either an int, # QString, QObject or a QWidget which is passed as argument to the slot # connected to the QSignalMapper. In the following example, clicking on the QML object makes the C++ object print a message, and vice-versa. Is there a way to clear QSignalMapper, or is QSignalMapper automatically cleared when an object is removed. map(sender) Parameters: sender – PySide6. So i thought about something like this. Imagine changing buttons to QComboBox or any other UI change. clicked. A QComboBox provides a means of presenting a list of options to the user in a way that takes up the minimum amount of screen space. The QSignalMapper class bundles signals from identifiable senders. QtCore. If you can't afford to lose the original arguments, or if you don't know the source of the signals (as is the case with QDBusConnection::connect() signals), then it doesn't really make sense to use a QSignalMapper. Qt does not do any conversion (cast) even if the sender is a QPushButton object that inherits from QWidget. 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. ). Similarly, the contents of a UI file can be retrieved using the. The specified plugin paths can be retrieved using the pluginPaths () function. There is no such signal mapped (const QPushButton&). The solution is to connect the clicked signal of the different buttons to the mapper directly (rather than through your. 3 Qt: the signal handler is not called when the signal is emitted. QtCore. QtCore. Much cleaner code and it’s easier to maintain and modify. QTimer::singleShot - forward parameter to SLOT called. I've recently encoutered a problem with QSignalMapper. qml. Simple painter application based on Qt Widgets. Main Page; Packages; Classes; Class List; Class Index; Class Hierarchy; Class MembersThe PySide. The mentioned message was logged only one time. The following example uses old-style signals and slots connections to explicitly specify the signals to be connected to slots in a Python subclass of QWidget. So this is like calling doSomething in the next event. This is less costly and will simplify the code. removeItem () in the connect method will actually try to call the self. Is there any relatively simple way for it? c++; qt; enums;Here is an easy way to get the 3D representation of an object. 中，我有以下信号：. QVariant or a generic interface is not provided by Qt. For strings and integers, you can use QSignalMapper. Unfortunately, all attempts of making this used QSignalMapper successfully in a similar situation. For example, the dynamically created buttons or objects in QStackedWidget. self. , you will call the same slot multiple times with single signal. 简介. Consider a card game. The class supports the mapping of particular strings or integers with particular objects using setMapping (). You can check the return bool and have a look to the output window of your application. Bug ID: 452419 Summary: not installed Product: systemdgenie Version: unspecified Platform: Neon Packages OS: Linux Status. The QSignalMapper class bundles signals from identifiable senders. 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. The syntax of a lambda expression is the following: [captured variables] (arguments) {. The Text Edit example shows Qt’s rich text editing facilities in action. It allows you to add add a parameter (in this case, probably an integer index to your vec) to signal, based on which object emitted it. " The answer by @kuba, below, is now a better one. 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. You can limit the size of the read buffer using setReadBufferSize () . See also Input/Output and Networking . 8, which signals and slots system was based on the use of macros. Jacobs on this Question, and was trying to create an app that will open multiple windows with different parameters, but it doesn't work, looks, like app is opening w. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. 按钮被点击触发信号激活 QSignalMapper的槽函数map ()，map ()会统一释放一个带有标记的信号，该信号触发定义的按钮槽函数，根据标记（ID、 QWidget 、QString）去判断到底. The setMapping function assigns a unique integer value (1 and 2) to each button. Calling QComboBox* combo = (QComboBox* )sender() in the slot fails, presumably because sender() is now the QSignalMapper. A combobox may be editable, allowing the user to modify each item in the list. void myclass::deleteButton (int i) { delete (Buttons. In this example, the QSignalMapper object is created and connected to the clicked () signal of two buttons. Mac OS X also has a "Find" clipboard. Also, make sure to register your struct to the Qt metatype system by using Q_DECLARE_METATYPE. map) checkbox_2. #include <QtGui> class W: public QWidget { Q_OBJECT public: W (QWidget *parent=0): QWidget (parent) { // Create. 511 7 7. py. QSignalMapper with signal argument and extra argument. The QSignalMapper class bundles signals from identifiable senders. You can trigger behaviors in response to user input, such as button presses or text input, or events in your own code. 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. 1 Answer. I'm having some troubles trying to pass a custom widget to a custom slot inside my Qt App. com if any conditions of this licensing are ** not clear to you. Method Documentation QSignalMapper. I got following qt message. The socket is created in our class constructor -. 详细说明 QSignalMapper 类捆绑来自可识别发送者的信号。. Then, create a standalone. If I correctly understood, each QGraphicsItem has special unique QComboBox. connect (m_socket, SIGNAL (stateChanged (QAbstractSocket::SocketState)),. In python this is actually not even an issue, and that class is not really required: you can just use functools. I ha to use repaint fonction to force th label to update regulary the display. I have a QTreeWidget in which each of its items has a QComboBox in a column. How to say QSignalMapper in French? Pronunciation of QSignalMapper with 1 audio pronunciation and more for QSignalMapper. The Simple Tree Model example shows how to create a basic, read-only hierarchical model to use with Qt’s standard view classes. QSignalMapper is the best solution to connect multiple signals to the same slot. Q&A for work. Below is an example of the use of QSignalMapper in Qt4/5. ; calling connect multiple times creates multiple connections i. Provide details and share your research!I'm trying to connect a button click to a function, and pass an int value, but keep getting an error: no matching function for call to Main::connect. com if any conditions of this licensing are ** not clear to you. ; From your. Since your "load" and "return to main menu" signals are being sent from the same sender object they will be mapped the same way. QSignalMapper with signal argument and extra argument. dheerendra Qt Champions 2022 14 Jan 2019, 22:11. Here are the examples of the python api PyQt5. Это лучшие примеры Python кода для PyQt5. –QObject::connect(signalMapper, SIGNAL(map), this, SLOT(MainWindow::switchPage)); this is wrong as you can see on the output during runtime and the return value of this function. QSignalMapper does not update parameter after choosing file. The class supports the mapping of particular strings or integers with particular objects using setMapping(). To be more explicit, I already have connected actions using QSignalMapper, but the slot function's parameter was a QString, which was fine since there is a QSignalMapper signal that has a QString parameter and it doesn't give any problem. It's actually a problem with QSignalMapper. Here you can get list of all widgets available in. Using a signal mapper. Constructs a QSignalMapper with parent parent. QSignalMapper does not update parameter after choosing file. Here my QToolButtons are in contained in QList. [slot] void QSignalMapper:: map This slot emits signals based on which object sends signals to it. Since then, Qt5 has been released and C++11 is now A Thing. 467. In keyboard. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. The cards are clickable, and lead to the same effect, so the use of QSignalMapper was obvious. I have followed the answer by X. connect. QSignalMapper * mapper = new QSignalMapper (this. We would like to show you a description here but the site won’t allow us. ** **/ #ifndef QSIGNALMAPPER_H #define QSIGNALMAPPER_H #ifndef QT_H #include "qobject. main. The class supports the mapping of particular strings or integers with particular objects using setMapping(). from pivy import coin import FreeCAD as App box = App. If I click onto a QPushButton, I want to set some text inside the corresponding QLineEdit. m_socket = new QUdpSocket (this); // connect activity signal for socket. What i want to achieve is a little different. (Going forward the goal will be to have the VerticalLineSegment s in. Follow edited Jan 10, 2017 at 18:49. So for example if you want to have a timer who. It behaves essentially like the above function. txt"));A. A quick look at the Qt docs for QSignalMapper (assuming that is what you're using based on the question title) states that the parameter for the mapped signal is const QString&. The quick-and-dirty way is to use connect () as usual, and then in your slot method, call sender () to find out which object sent the signal. 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. Is there a more correct way to do. Stack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Talent Build your employer brand ; Advertising Reach developers & technologists worldwide; Labs The future of collective knowledge sharing; About the companyTextEdit Example#. The simplest way to set multiple events to a simple behaviour is to do it in pure python: for edit in LineEdits: edit. But i know it is possible to do it with strings. Qt does not do any conversion (cast) even if the sender is a QPushButton object that inherits from QWidget. A QSignalMapper object is one that emits a mapped() signal whenever its map() slot is called. 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1. 1. Now, consider discarding those cards, to draw new ones.