Use mapped (QWidget*) and change your slot to have the same signature: button_pushed (QWidget*). Show Printable Version; 13th January 2008, 21:14 #1. You cannot connect a whole list at once. 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. Connect (stackedwidget->currentactivewidget,SIGNAL (OnAction ()),this,SLOT (PrivateSlot ())); PrivateSlot () is a slot declared privately. Create a signal mapper: signalMapper = QSignalMapper () Associate a mapping of type int with the callback function: signalMapper. QSignalMapper Class The QSignalMapper class bundles signals from identifiable senders. 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 QDataWidgetMapper class makes it easy to relate information from a model to widgets in a user interface. Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-Share Alike 2. It throws "F libc : Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x2787c in tid. We connect each button's signal to the signal mapper's () slot, and create a mapping in the signal. But how can I pass (qint64,qint64) to my own function? I pass the id to my slot, but I loss (qint64,qint64)Here's where I run into the issue: Because the simulation is process-intensive, I leverage the Python multiprocessing library to spawn multiple processes in order to speed up runtime. At least, that is the safest way to do a cast. We connect each button’s clicked() signal to the signal mapper’s map() slot, and create a mapping in the signal mapper from. connect (self. There is a problem in the connection since the compiler cannot understand it since there are signal and slots overloads. Also, since you want to do it at. Both model and series properties can be used to manipulate the data. SIGNAL ("clicked (int)")) Having self. On the #pyqt channel on Freenode, lauri asked about connecting identically-named signals with different parameters from QSignalMapper to slots. 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. You cannot connect a whole list at once. More. Looking at the documation you can see, that the QSignalBlocker provides a __enter__ and a __exit__ function. We connect each button's signal to the signal mapper's () slot, and create a mapping in the signal. So one would ideally use a for loop. The connection is established as follows: 1. Frequently Used Methods. Hope you found it useful. connect (mapper. How Connecting Works. The QDataWidgetMapper class allows information obtained from a model to be viewed and edited in a collection of widgets instead of in an item view. Any help would be really appreciated. value ("image"). void QSignalMapper::mapped ( const QString & text) [signal] This is an overloaded member function, provided for convenience. So far we've created a window and added a simple push button widget to it,. This signal is emitted when map() is signaled from an object that has a string mapping set. Qt Base (Core, Gui, Widgets, Network,. This topic has been deleted. QSignalMapper class bundles signals from identifiable senders. I want to make a downloader by Qt. It behaves essentially like the above function. More. The object's mapped widget is passed in widget. 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. 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 slot emits signals based on the sender 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. . Replies: 1 Views: 2,998; Last Post By: Last Post: 3rd January 2017 10:07 by anda_skoa . 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). The same functionality in python can be obtained with functools. Hide table of contents sidebar. First get your image on the widget, then move that code to a worker object. Only users with topic management privileges can see it. A list of texts is passed to the constructor. You can then use QObject::sender () within the slot to determine which object emitted a signal. I realize that this actually works when more than one signal of different types is sent, e. 15. QSignalMapper can not be used for that, but the class is quite simple to re-implement and specialize for your needs. Qt Signal mapper and sending QLabel by reference and OpenCv 2. [virtual] QSignalMapper:: ~QSignalMapper Destroys the QSignalMapper. The class supports the mapping of particular strings or integers with particular objects using setMapping (). If I got it right, you just want to unmap a button as soon as it was clicked and corresponding client was disconnected. QSignalMapper. 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. Qt Signal mapper and sending QLabel by reference and OpenCv 2. 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. 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. Keep in mind, it does not disconnect button. This topic has been deleted. 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 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. Use mapped (QWidget*) and change your slot to have the same signature: button_pushed (QWidget*). All. The QDataWidgetMapper class allows information obtained from a model to be viewed and edited in a collection of widgets instead of in an item view. The example above can be rewritten simpler without QSignalMapper by connecting to a lambda function. Let's call this hypothetical class "Stuff". However, it is sometimes necessary to use input widgets which offer choices to the user, such as QComboBox, in conjunction with a widget mapper. The only function that we need to implement is the constructor: A list of texts is passed to the constructor. Qt Signal mapper and sending QLabel by reference and OpenCv 2. Python QSignalMapper - 59 examples found. Then my earlier suggestions still stand. See also setMapping(). ) summary refs log tree commit diff stats Using a signal mapper. ) summary refs log tree commit diff statsUsing a signal mapper. This signal is emitted when map() is signaled from an object that has a string mapping set. But signal mapper doesn't send any signal to the slot. 5. 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 list of texts is passed to the constructor. self. get (), &senderObject::signal, this, [this] (int int_val, std::string str_value) {function (int_val,str_value)}); Maybe there is an overload template. MainWindow::MainWindow (QWidget *parent) : QMainWindow (parent) , ui (new Ui::MainWindow) { ui->setupUi. Just running the program no. 2. Just try with following and see how things work. See also setMapping(). You can trigger behaviors in response to user input, such as button presses or text input, or events in your own code. void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. Only users with topic management privileges can see it. You can't execute code inside SLOT (). This topic has been deleted. The QSignalMapper is used to re-emit signals with optional parameters. RamzyKaram92 last edited by . 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. Qt Signal mapper and sending QLabel by reference and OpenCv 2. 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. qt. QSignalMapper is a wonderful class to organize the work of the signals and slots dynamically created objects. Only users with topic management privileges can see it. [signal] void QSignalMapper:: mappedWidget (QWidget *widget) This signal is emitted when map() is signalled from an object that has a widget mapping set. I have three classes, that need to cooperate. 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 QSignalMapper class bundles signals from identifiable senders. 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. QSignalMapper* signalMapper = new QSignalMapper(this); QString val = tableUsers - >item ( y, x)- >text (); The solution is very simple. This was particularly true in older versions of the software, that is, and relied on Qt 4. QGridLayout *gridLayout = new QGridLayout; for. This topic has been deleted. More. public: QSignalMapper* windowLblSignal; cv::VideoCapture CapObjLabel; cv::Mat orignFrame; QImage qimgOriginal; QTimer* tmrWindowTimer; public: ImgClass(); void waitForUser(QLabel *windowLabel); public slots: void changeWindowLabel(QLabel* windowLabel); i've tried to insert QObject or QWidget but it didn't work also sorry, it is my. It behaves essentially like the above function. Have a look at QSignalMapper's documentation, there's an example of how it works. It really doesn't need know about that QLabel. But we also want to know which button triggered the signal. 20. void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. 14. Sometimes, however, we would like the slot to behave slightlydifferently depending on which widget invoked it. The best wireless auditing app for Tango! Signal Mapper displays detected signal strengths over auto-generated 3D scanned floor plans, providing the ultimate utility for analyzing wireless signal coverage. Online Casinos Reviews. 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,. Note that in mostQt Signal mapper and sending QLabel by reference and OpenCv 2. This function was introduced in Qt 5. Forums; Tutoriels; Magazine; FAQs; Blogs; Projets; Chat; Newsletter; Accueil Actualités IT Pro Conception Cycle de vie du logiciel ConceptionThe QSignalMapper class bundles signals from identifiable senders. This topic has been deleted. The object's mapped integer is passed in i. Note: If an empty string is set as the LabelFormat, it will be ignored, and the series pointLabelsFormat will be used. QSignalMapper* signalMapper = new QSignalMapper(this); QString val = tableUsers - >item ( y, x)- >text ();The solution is very simple. 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. QSignalMapper extracted from open source projects. Qt Signal mapper and sending QLabel by reference and OpenCv 2. The SQL Widget Mapper example shows how to use a map information from a database to widgets on a form. Any model derived from QAbstractItemModel can be used as the source of data. RamzyKaram92 last edited by . At least, that is the safest way to do a cast. This signal is emitted when map() is signalled from an object that has a string mapping set. Signal Types. Alternatively with C++11 and up, you can use a lambda to extend your connection with a pointer to the sender. auto chart =newQChart; chart->setAnimationOptions(QChart::AllAnimations); The first line of the code below creates new bar series. See also setMapping(). Now i want to map all of them in a signal mapper. )), workspace, SLOT(setActiveWindow(QWidget. 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. RamzyKaram92 last edited by . void QSignalMapper::removeMappings ( const QObject * sender )void QSignalMapper::map ( QObject * sender) [slot] This is an overloaded member function, provided for convenience. It makes it easier to see how a modification to the model's data affects the chart. . Hi, I have a slot that I'd like to connect to. RamzyKaram92 last edited by . 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. 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. When you receive a signal, map (), look at QObject::sender () ( link) as the key in the map to make the emit in your turn. Qt Code: Switch view. Then you connect your signal mapper to the custom signal checkBoxChecked, instead of the standard toggle (bool) signal. For example, in the code snippet below, the QLineEdit object. void QSignalMapper::removeMappings ( const QObject * sender )void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. It doesn't work this way. 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. 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. It really doesn't need know about that QLabel. QtCore. Or just change On_clicked into slot and connect signal mapped (int) to it (use SLOT keyword then). connect (signalMapper. 4351. Good morning, sehr geheerte Damen und Herren! :D I have problem I cannot crack. Then my earlier suggestions still stand. removeItem () in the connect method will actually try to call the self. ; From your. So one would. The QSignalMapper class bundles signals from identifiable senders. Only users with topic management privileges can see it. Download and install the Qt SDK; Source Code [] Main. void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. You. See also setMapping(). removeItem method rather than providing the subsystem an address to connect the function. [virtual] QSignalMapper:: ~QSignalMapper () Destroys the QSignalMapper. When I'm doing a mapping and that the argument passed to the function is an int, everything works just fine, but when it is a string, nothing happen. Qt Quick TableViews examples - Pixelator. All of them should go inside 1 slot. 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. Signal is the base implementation of the Signal and can be created on a per instance level. Keep the image processing in BinaryImage and emit the QPixmap when ready. On running the application, we can click the button to execute the action (slot). Using a QSignalMapper for that task is just an overkill. QtCore. mappedObject (QObject * object) void. You can see this, when you look at the original Qt-documentation for QSignalBlocker and see the __enter__. 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 topic has been deleted. QGridLayout *gridLayout = new. QXYSeries::PointConfiguration::LabelFormat (since Qt 6. Note that in mostI have been trying to implement signal mapper. 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. The class supports the mapping of particular strings or integers with particular objects using setMapping(). RamzyKaram92 last edited by . void QSignalMapper::removeMappings ( const QObject * sender )The QObject-based version has the same internal state, and provides public methods to access the state, but in addition it has support for component programming using signals and slots. 8 doesn't have SLOT getting signal from 'mapped'. void QSignalMapper::mapped ( const QString & ) [signal] This is an overloaded member function, provided for convenience. This signal is emitted when map() is signaled from an object that has a string mapping set. This signal is emitted when map() is signaled from an object that has a string mapping set. See also setMapping(). Lets say they are named pushbutton1, pushbutton2, etc. Simply use a QMap<QObject*,ValueStruct>, where ValueStruct keeps your arguments. We strongly advise against using it in new code. include <QtGui/QApplication> include "buttonwidget. If the code is longer than one screen at normal point size, it might be better if you provide a rationale and a link, or just put it on a separate page. The class supports the mapping of particular strings or integers with particular objects using setMapping(). Thread: ? about QSignalMapper. This signal is emitted when map() is signaled from an object that has a string mapping set. Signals and slots are made possible by Qt's meta-object system. Qt Library. The solution is to connect the clicked signal of the different buttons to the mapper directly (rather than through your. Again, we create a Window class with. Slot Apps for Real Money. A signal mapper is constructed and for each text in the list a QPushButton is created. It is provided to keep old source code working. This blog is part of a series of blogs explaining the internals of signals and slots. QSignalMapper does not provide functionality to pass signal parameters. The model mapper keeps the pie series and the data model in sync. This is the quick, relatively easy, and sloppy way. You can only use the signals that exist in QSignalMapper. It allows mapping one or more signals from different objects to a single slot. I have been trying to implement signal mapper. 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 signaled from an object that has a string mapping set. setMapping (checkBox, int)Smilies are On. The class supports the mapping of particular strings or integers with particular objects using setMapping(). 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. 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. void QSignalMapper::removeMappings ( QObject * sender) Removes all mappings for sender. 15. ButtonWidget :: ButtonWidget ( const QStringList & texts, QWidget * parent) : QWidget (parent) { QGridLayout * gridLayout = new QGridLayout ; for ( int i = 0; i < texts. setMapping extracted from open source projects. This why I use signalMapper so that, immediately after the toggle, I can pass a reference to the toggled checkbox as a parameter to my custom slot. A signal mapper is constructed and for each text in the list a QPushButton is created. 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. Finally we connect the signal mapper's mappedString() signal to the. It is subclassed from QPushButton and also it holds a private member:private: qint16. A section is a column of a model if the orientation is horizontal (the default), otherwise a row. The class supports the mapping of particular strings or integers with particular objects using setMapping (). 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,. void QSignalMapper::removeMappings ( const QObject * sender )NEON ® Signal Mapper automatically geo-references the signal data captured by 3rd party test equipment, producing 2D/3D map visualizations and detailed reports in real-time. Signal is the base implementation of the Signal and can be created on a per instance level. The Simple Widget Mapper example shows how to use a widget mapper to display data from a model in a collection of widgets. The QSignalMapper class bundles signals from identifiable senders. 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. QSignalMapper. The object's mapped integer is passed in i. 3 Qt: the signal handler is not called when the signal is emitted. io The QSignalMapper class bundles signals from identifiable senders. The object's mapped widget is passed in widget. Good morning, sehr geheerte Damen und Herren! :D I have problem I cannot crack. . The workaround is to explicitly specify a signal that is compatible with map (). __init__ (self, QObject parent = None)The parent argument, if not None, causes self to be owned by Qt instead of PyQt. Every time the current index changes, each widget is updated with data from the model via the property specified when its mapping was made. 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. However, it breaks encapsulation. map) Tonight's PyQt snapshot will be smarter about finding a usable Qt slot before deciding that it needs to. 使用QSignalMapper 传递参数： 其中，index可以换作其他的参数。void QSignalMapper::mapped ( int i) [signal] This signal is emitted when map() is signalled from an object that has an integer mapping set. Go to Qt Creator Project settings and check the all ABIs like my screenshot. What is the function of signal mapper? A signal mapper is constructed and for each text in the list a QPushButton is created. The solution is to connect the clicked signal of the different buttons to the mapper directly (rather than through your LoadGameMenu. 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. This slot emits signals based on the sender object. void QSignalMapper::mapped ( const QString & text) [signal] This is an overloaded member function, provided for convenience. Qt Signal mapper and sending QLabel by reference and OpenCv 2. Then my earlier suggestions still stand. Combo Widget Mapper Example. 1) QSignalMapper maps a QObject* sender to a (int, string, QWidget* or QObject*). But, this example code from 4. The connection is established as follows: 1. . You can then use QObject::sender () within the slot to determine which object emitted a signal. e. Adds a mapping so that when map () is signaled from the given sender, the signal mapper ( identifier) is emitted. There is no such signal mapped (const QPushButton&). 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. mapper, QtCore. A list of texts is passed to the constructor. I am able to run my android qt app on a real android 11 (general mobile G510) mobile phone BUT I cannot run same app in a android virtual device. SQL Widget Mapper Example. Signals (and slots) allow you to connect disparate parts of your application together, making changes in one component trigger behavior in another. [virtual] QSignalMapper:: ~QSignalMapper () Destroys the. The only function that we need to implement is the constructor: SIGNAL (clicked ()) SLOT (map ())); signalMapper. This signal is emitted when map() is signaled from an object that has a string mapping set. This function was introduced in Qt 5. Share. 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 topic has been deleted. [signal, since 5. 5 License. maybe you should try dynamic_cast<> and only access the data if the pointer to the casted object is valid. The only function that we need to implement is the constructor: A list of texts is passed to the constructor. [signal] void QSignalMapper:: mappedWidget (QWidget *widget) This signal is emitted when map() is signalled from an object that has a widget mapping set. Qt Signal Slot Mapper Usb; Qt Signal Slot Mapper Software; Qt Signal Slot Mapper App【Qt】QSignalMapperは まいそうされます。 - カンテラの光の下で; 概要. void QSignalMapper::mapped ( int i) [signal] This signal is emitted when map() is signalled from an object that has an integer mapping set. Now inside of readCombo i want to read a string and pass it to change picture: QString imageFileName = xmlreader->attributes (). It behaves essentially like the above function. Only users with topic management privileges can see it. These are the top rated real world Python examples of PyQt5. Ask Question Asked 7 years, 7 months ago. The class supports the mapping of particular strings or integers with particular objects using setMapping(). This blog is part of a series of blogs explaining the internals of signals and slots. A. The QSignalMapper class bundles signals from identifiable senders. partial. 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 QSignalMapper class bundles signals from identifiable senders. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters. I have used the example code below. This topic has been deleted. Qt Code: Switch view. For example, the dynamically created buttons or objects in QStackedWidget. You can't execute code inside SLOT (). 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. See also setMapping(). Re: Passing a pointer in Signal/Slot Connection. 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. Again if you really want to pass the signal up the heirarchy, emit. It behaves essentially like the above function. SIGNAL ("clicked (int)")) Having self. g. 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. A TableModel is a natural choice for the model. Then my earlier suggestions still stand. mapped [int]. 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. if you call. 20. There are 4 types of Signals included. 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. Signals and slots are used for communication between objects. Signals and slots are used for communication between objects. in your component connect the source signal to a custom slot that dispatches based on the qstring value. mapper. Template:Abstract. 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 . The class supports the mapping of particular strings or integers with particular objects using 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. There is a signal in QNetworkReply, downloadProgress(qint64,qint64) I hava many download task, so I use QSignalMapper to process the signal. A list of texts is passed to the constructor. You can invoke a slot with QMetaObject::invokeMethod. The class supports the mapping of particular strings or integers with particular objects using setMapping (). So i am using QSignalMapper. I have been trying to implement signal mapper. See also setMapping().