What's more, I can run the demo of MoveIt Quickstart in RViz correctly:That's created by this macro. main. Hey Something I wanted to follow up as I noticed I'm not the only with the issue. You need to create your own factory that will register functors that will call qRegisterMetaType in runtime. As G. Memory handling for class with dynamically allocated memory. (Make sure 'MyStruct' is registered using qRegisterMetaType (). Kind Regards, Sy. In C++ if you wan't to use some type in queued connection type you should call qRegisterMetaType<MyType> ("MyType"). I created a. 5 and Qt Version 5. g. 15. Good workaround: you may register your type with Q_DECLARE_METATYPE ( IBase * ) macro and wrap your. hskoglund last edited by . Solution 1: somewhere. After about 20 seconds of running LOAM, the laserOdometry module crashes with [laserOdometry-2] process has died [pid 6983, exit code -11, cmd /home/ab. 15. All the resources I found online point to a C++ syntax/documentation. There's no compile time error, but when I run. If I register QVector I can't dissconnect this signal and the signal is emited. QtのAPIのドキュメントに、thread-safeと書いてない限りは、QMutex等を使って自分で排他をする必要がある。. To use the enum, you have to explicitly include the full. Currently I have a 2d array which represents the game board. emit (foo_text) def settext ( self, text ): print (text) Im sure you guys get this alot but im trying to thread and im getting this error: (Parent is QTextDocument (0x1243bfd4290), parent's thread is QThread (0x12437dd1260), current thread is. rep file extension, short for Replica. 1,609 4 22 34. As far as I found before, Qt objects should not be accessed directly. ) which are updated by simulation code. ) INFO:cfclient. cpp</code> file implementing <code>YourType</code>. If _message is a string then the slot must have the argument: foo_text = "Foo" self. All. ) changing rowCount in the main thread or commenting out setRowCount call in change_row_count() makes those errors. Just installing it did not work for me. Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered. QSignalSpy itself is a list of QVariant lists. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. 8 data bits. And this should be used for each exe/dll instance. an int and a std::string. Nope, registering with qRegisterMetaType<std::vector<int>>() has same effect as not registering at all (using QVector<int> works without registration, but does not expose length, either). You can create Q_GADGETS in QML using a C++ factory object registered to be accessible in QML, and a Q_INVOKABLE function in this factory which returns an instance of the Q_GADGET object. the type name must be specified without the class, as in. It enables things such as QVariant wrapping of custom types, copy of queued connection arguments, and more. ) The form here shows the exactly same problem but I can't use signal and slot as. launch" i got. Even if it works now, it may fail with new Qt versions. Thanks for the code snippet. Jun 13, 2021 at 19:37. 在使用 qRegisterMetaType<int>("int&");注册一个自定义类型给线程后，就出现“启动程序失败,路径或者权限错误”的提示，之后程序就一直编译不过去。不管删除了相关的文件后，或者重新构建，都是一样的问题。 但是，在不断的摸索后，突然之间就可以了，后面实验. 1 Reply Last reply . 3k 33 33 silver badges 58 58 bronze badges. This article will describe what you. void QVariant:: clear (). It seems QVariant is not direct part of queued connections mechanism. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Qt Base (Core, Gui, Widgets, Network,. The following example records all signal emissions for the clicked () signal of a QCheckBox:Step 1 (mark for MOC), build some QObjects That pattern uses Q_PROPERTY and Q_OBJECT and the MoC tool. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. Data Type Conversion Between QML and C++. The. 3. You always need to inform the compiler that you are specializing a template by placing template<> in front of it. ) So it seems to be a multi-threading issue caused by this instruction connect (process,&QProcess::started, [this. ) QObject::connect: Cannot queue arguments of type 'QVector' (Make sure 'QVector' is registered using qRegisterMetaType(). Here’s the list of what changed: QVariant used to forward isNull () calls to its contained type – but only for a limited set of Qt’s own types. 12. The Rep lica C ompiler (repc) generates QObject header files based on an API definition file. QT 信号和槽传递自定义对象问题. Foo and Foo* are different types and need to be registered separately. 0. QVariants are important in QML because they used to store the arguments from signals and slots, and also get values from the QMetaProperty system. The correct syntax is Q_DECLARE_METATYPE (std::string) without the ;. @SGaist if you see the original question I posted the contents of the devicepresence. If a field is empty, keep it in the result. The QObjectList class is defined in the <QObject> header file as the following: typedefQList<QObject*>QObjectList; The first child added is the first object in the list and the last child added is the last object in the list, i. ) このような場合は以下の通り qRegisterMetaType() の引数を設定することで回避できることがある。You can safely remove the const, even if the real signature of SendData and ReceiveData is const u_char*. Returns true if the write succeeded; otherwise returns false. This function requires that T is a fully defined type at the point where the function is called. e. Any QQmlContext's created on this engine will be invalidated, but not destroyed (unless they are parented to the. 因为没有指定 connect的链接方向 Qt::DirectConnection. ) QObject::connect: Cannot queue arguments of. 0. (Make sure 'QVector<QVector<int> >' is registered using qRegisterMetaType (). (Make sure 'QVector<int>' is registered using qRegisterMetaType(). There is a name index for fast lookup of the meta type id. In my module tests, I turn the card up and down, and can verify that the number of signals are increasing using QSignalSpy. This requires the exchanged data to be of a type that is recognizable by the engine. akshatrai91 7 Jan 2021, 06:21. Normally you would do this in main () or. Hello, Can someone tell me about how to register a metatype in pyqt5. You'll need Q_DECLARE_METATYPE () if you want to store your type within a QVariant and you will additionally need qRegisterMetaType<> () if you want to dynamically create and destroy objects of that type at runtime, mostly for queued signal and slots connections or the QObject property system. 在使用 qRegisterMetaType<int>("int&");注册一个自定义类型给线程后，就出现“启动程序失败,路径或者权限错误”的提示，之后程序就一直编译不过去。不管删除了相关的文件后，或者重新构建，都是一样的问题。 但是，在不断的摸索后，突然之间就可以了，后面实验. And this should be used for each exe/dll instance. Use Q_DECLARE_METATYPE (std::string) in one of your headers. That's created by this macro. A QItemSelection describes the items in a model that have been selected by the user. 2. the connect () call returns true, but when the signal is emitted, Qt outputs this: QObject::connect: Cannot queue arguments of type 'uint64'. Now, this simple class holds small samples of. 16. It can be done with some global container, but because in C++ order of initializing variables is not defined - it may be not trivial. Even though we do not intend to use the type with QVariant in this example, it is good practice to also declare the new type with Q_DECLARE_METATYPE (). Qt::QueuedConnection，则会发送一个QEvent，并在应用程序进入主事件循环后立即调用该成员。. The following code allocates and destructs an instance of MyClass: The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. Instead, the following lines have been added to the adding. multithreaded software and I am getting the warning says: (Make sure. The Qt doc on qRegisterMetaType explicitly says : T must be declared with Q_DECLARE_METATYPE (). Note that if you intend to use the type in queued. 1. QObject: Cannot create children for a parent that is in a different thread. The entries are addressed via startAddress () and the valueCount () number of contiguous entries. 13. Detailed Description. bool QLocalSocket. I created a. 就是说 类实列化一次，QML中可以直接使用这个类。. 则QML中可直接使用 MainController。. template <typename T> struct QMetaTypeId<Container<T>>. Thanks a lot for that!. get (), &senderObject::signal, this, [this] (int int_val, std::string str_value) {function (int_val,str_value)}); Maybe there is an overload template. To make the diagnosis of test failures easier, the results of. cpp; so you will have. ) QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). ) QObject: Cannot create children for a parent that is in a different thread. qRegisterMetaType () is called to register the TYPE and generate a TYPE ID. g. 使用此连接类型在同一线程中的对象之间进行. You can use the tags to annotate your methods. . text_changed. h" enum Color { RED = 0, BLUE, GREEN }; Q_DECLARE_METATYPE (Color) #endif /* ENUMS_H */. You should place Q_DECLARE_METATYPE (QSqlRecord) in only one header and then just include it everywhere it is needed. FollowQObject::connect: Cannot queue arguments of type 'QProcess::ProcessError' (Make sure 'QProcess::ProcessError' is registered using qRegisterMetaType(). when pressButtonThread is triggered: QObject::connect: Cannot queue arguments of type 'QTextBlock'. For a signal-functor connection without a context object, it is the only way to selectively disconnect that connection. beginGroup("references/"); QStringList keys = settings. call qRegisterMetaType() to register the data type before you call QMetaMethod::invoke(). clicked. @reddy9pp said in QObject::connect: Cannot queue arguments of type 'std::string' (Make sure 'std::string' is registered using qRegisterMetaType(). self. e. uint8_t is the typedef for unsigned char . Here my test code and example: #include <QCoreApplication> #include <QDebug> #include <QMetaType> #include <QRect> #include <QMetaObject> class. Even though qRegisterMetaType(). The Rep lica C ompiler (repc) generates QObject header files based on an API definition file. [since 6. I realize that this actually works when more than one signal of different types is sent, e. e. The QML engine provides built-in support for a. If I save the image to disk in the DB thread just after emitting the signal, it is good. Detailed Description. There's no compile time error, but when I run. You can connect a signal to a slot with connect () and destroy the connection with disconnect () . 2 Answers Sorted by: 3 You do not need to call qRegisterMetaType () to use a type with QVariant. I have a C++ class called MyClass. 2、在类型定义完成后，加入声明：Q_DECLARE_METATYPE (MyDataType); 3、在main ()函数中. tab) self. Q_DECLARE_METATYPE (QSqlRecord) has to be outside any classes and namespaces. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. button. std::shared_ptr does not let you assign a plain pointer to it directly. ICS ICS. See also Q_DECLARE_METATYPE() and qRegisterMetaType(). ) On any update in C++ side list, modify the qml data as well. How to properly use qRegisterMetaType on a class derived from QObject? I couldn't understand from the answer to where I have to define the specialization of qMetaTypeConstructHelper. Q&A for work. akshatrai91 7 Jan 2021, 06:21. When data values are exchanged between QML and C++, they are converted by the QML engine to have the correct data types as appropriate for use in QML or C++. h which looks like: #ifndef ENUMS_H #define ENUMS_H #include <QtDBus> #include "enumDBus. e. Warning: To make this function work with a custom type registered with qRegisterMetaType(), its comparison operator must be registered using QMetaType::registerComparators(). I intially installed a later version of Qt but then reverted back to Version 5. " and: "Warning: This function is useful only for registering an alias (typedef) for every other use case Q_DECLARE_METATYPE and qMetaTypeId() should be used instead. Last updated at 2016-07-08 Posted at 2015-11-16. And even you make right signature, you will not be able to connect that signal and slot due to their signature mismatch. layoutChanged. rep file extension, short for Replica. You can use Qt's typedef for unsigned char: quint8 and you don't need to register it. Instead, we should pass weak_ptr to a shared_ptr. tag(); // prints MY_CUSTOM_TAG. ChildAdded and ChildRemoved events are sent to objects when children are added or removed. The physical memory sizes returned include the memory from all nodes. ;. qRegisterMetaType<QSqlDatabase>("QSqlDatabase"); Just changing the signal to this form: void dbConnected(QSqlDatabase *db); And, in the slot side I'll use something like this: void onDBConnected(QSqlDatabase * const db); I'm concerned with the usage of db (as in the beginning I've made the reference const), so I make it const here. I had to uninstall it first, then reinstall it: # upgrade pip python3 -m pip install --upgrade pip # uninstall python3 -m pip uninstall PyQt5 python3 -m pip uninstall PyQt5-sip python3 -m pip uninstall PyQtWebEngine # reinstall python3 -m pip install PyQt5 python3. The factory must be set before executing the engine. It will return the same result if it was called before. qRegisterMetaType<ProcessHandle*>("ProcessHandle*"); qRegisterMetaType<ProcessHandle*>("ProcessHandle*const"); For the purposes of queuing arguments, const pointer is equal to normal pointer, since it's being copied not changed. In short, I get following error: QObject::connect: Cannot queue arguments of type 'cv::Mat' (Make sure 'cv::Mat' is registered using qRegisterMetaType (). Undeclared QMetaObject::SuperData. For example if you have a customwidgetscript. In QML, the meta-type system is the only way that QML engine can access C++ structures from a QML environment. MainWindow win; win. Qt documentation specifically states that qRegisterMetaType<T>() must be called for a type to work in the Qt property system. Type names can be registered with QMetaType by using either qRegisterMetaType () or registerType (). Add a comment | 5 I believe the following is state is not defined in your MyThread class. In C++ if you wan't to use some type in queued connection type you should call qRegisterMetaType<MyType> ("MyType"). Otherwise, returns QPartialOrdering::Less, QPartialOrdering::Equivalent or QPartialOrdering::Greater if lhs is less than, equivalent to or. qRegisterMetaType<QSqlDatabase>("QSqlDatabase"); Just changing the signal to this form: void dbConnected(QSqlDatabase *db); And, in the slot side I'll use something like this: void onDBConnected(QSqlDatabase * const db); I'm concerned with the usage of db (as in the beginning I've made the reference const), so I make it const here (in the slot. Your uint8_t is atomic and you don't need to register it, just use. Yet, the first line is invisible and this line becomes visible only if we click on it! Very weird! QObject::connect: Cannot queue arguments of type 'QTextCursor'. When a new folder is selected I load the thumbnails and. Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered. Be very careful as cv::Mat is not implicitly shared, it is just shared (i. If you wanted to user the new-style signals, then it would look more like: class TwitterThread (QThread): newStatuses = pyqtSignal (object). Detailed Description. connect(self. (Make sure 'QQuickChangeSet' is registered using qRegisterMetaType (). QSignalSpy can connect to any signal of any object and records its emission. To make the type known to this class, we invoke the Q_DECLARE_METATYPE () macro on the class in the header file where it is defined: Q_DECLARE_METATYPE(Message); This now makes it possible for Message values to be stored in QVariant objects and retrieved later. Then, connect this signal to a slot that will do the actual update of the data. It is almost. When: when you need to pass arguments to a queued connection or to enable creation of objects at run-time. 048771190]: Out drawPath [ INFO] [1432901455. OTOH, passing it by value in lambdas too is dangerous and can cause memory leaks. childKeys();@J. Yet, the first line is invisible and this line becomes visible only if we click on it! Very weird! QObject::connect: Cannot queue arguments of type 'QTextCursor'. QAbstractSocket is the base class for QTcpSocket and QUdpSocket and contains all common functionality of these two classes. ) But if I change the Q_DECLARE_METATYPE call to: namespace my_namespace { Q_DECLARE_METATYPE(BathyHint) } everything workes fine. In C++ if you wan't to use some type in queued connection type you should call qRegisterMetaType<MyType> ("MyType"). cpp file. a copy of a cv::Mat object will point to the same data as the copied from item). I understand that it has to do with Qt library but in which cpp file i have to put the argument ? The argument is this right ? qRegisterMetaType<QVector<int> >. – thuga. To enable creation of objects at run-time, call the qRegisterMetaType () template function to register it with the meta-object system. The only changes were made to initArgs and appendArgs functions. Doc states:. Saved searches Use saved searches to filter your results more quicklyI get a solution to the problem of "Qmqtt QObject::connect: Cannot queue arguments of type 'ClientState' (Make sure 'ClientState' is registered using qRegisterMetaType(). If you use queued connections, you'll need to call qRegisterMetaType() too. Also, to use type T with the QObject::property() API, qRegisterMetaType() must be called before it is used, typically in the constructor of the class. You are looking for the Q_ENUM () macro. @RIJIK "very unlikely" doesn't mean never ever. Even though we do not intend to use the type with QVariant in this example, it is good practice to also declare the new type with Q_DECLARE_METATYPE(). For pointer types, it also requires that the pointed to type is fully defined. This function was introduced in Qt 5. More frustrating is I've found PySide documentation alluding to the use of qRegisterMetaType, but I can't find out where to call it from. The key bit here is that the handle. The central feature in this model is a very powerful mechanism for seamless object communication called signals and slots. I created a. complains that the metatype isn't registered. QPainter::begin: Paint device returned engine == 0, type: 3 QPainter::setFont: Painter not active QPainter::setPen: Painter not active [ INFO] [1432901455. 默认会发送给主线程即默认的连接Qt::AutoConnection ，如果是多线程的话就是Qt::QueuedConnection了，所以要明确指定。. QSignalSpy itself is a list of QVariant lists. The default value is Data8, i. You have to register your custom type for queued signals because by registering it, Qt can make a copy of it in its event loop (which certainly uses QVariant) and pass it as argument later (when the original passed value is long since out. Detailed Description. " Currently I have no UI implemented (yet!). For pointer types, it also requires that the pointed to type is fully defined. However, as you need the type to be. You get this because you are creating the QNetworkAccessmanager in the constructor of Citizen, which is being called in the "original" thread. Turns out this was caused by the ipython magic "%matplotlib qt" in my startup script, which would try to use qt4. By convention, these files are given a . E. call qRegisterMetaType with the name specified, else reading properties. 我们知道类中的成员函数并不一定会被调用(即，该宏并不确保类型被注册到MetaType)。 通过qRegisterMetaType可以确保类型被注册; 两个qRegisterMetaType 的联系如果还希望使用这种类型的引用，可同样要注册：qRegisterMetaType<TextAndNumber>("TextAndNumber&"); 版权声明：本文为wangzhiqian7hao原创文章，遵循 CC 4. 11. Hello, Can someone tell me about how to register a metatype in pyqt5. I found a solution for my problem: First create a new header file called enums. Call this function if you need QLocalSocket to start sending buffered data immediately. childEvent (event) # Parameters:. The QObjectList class is defined in the <QObject> header file as the following: typedefQList<QObject*>QObjectList; The first child added is the first object in the list and the last child added is the last object in the list, i. QObject::connect: Cannot queue arguments of type 'QList<QPersistentModelIndex>' (Make sure 'QList<QPersistentModelIndex>' is registered using qRegisterMetaType(). In that case, I think you need to register them. 1 Answer. e. ;. 2. qRegisterMetaType 将某类型注册中 MetaType 系统中. 2、在类型定义完成后，加入声明：Q_DECLARE_METATYPE (MyDataType); 3、在main ()函数中. The following code allocates and destructs an instance of MyClass:The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. error C2059: syntax error : 'string' warning C4667: 'int qRegisterMetaType (void)' : no function template defined that matches forced. However, you shouldn't rely on Qt::QueuedConnection without registering the arguments types using qRegisterMetaType. . You can define one with the enum keyword. Detailed Description. Also you may need to use qRegisterMetaType function. In variant 1 the call is invoked immediately like in direct connection. Then the TYPE ID is saved in local static vairable metatype_id. The application may need to relay this clicking event to other applications. Haven't tried it yet but it appears to check the permissions established in the manifest(?). qml:17: Error: Unknown method parameter type: const Person*. f. Now, when you send some data, it is copied. As the docs state: Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template-based functions. A more complex program sending QSharePointer objects using slots has a similar situation with GDB, that can be reproduced with the previous example. If you want to pass IBase * between different threads, you need to register class with qRegisterMetaType<IBase *> () call; It is bad practice to pass pointers throught singals, because it is hard to control lifetime of passed objects. I'm introducing myself to PyQt5 through one of its included examples. When a signal is emitted, the corresponding signal handler is invoked. 1. . The errors you are getting are making it clear that it wouldn't work with const anyway you twist it, because that's not how the API is designed, because while you can pass non-const objects to const functions, you cannot do the opposite for reasons that should be obvious. ) Bug is reproducable only if a queued connection is used (when objects are in different threads or explicit Qt::QueuedConnection is used) and MyType is declared inside a namespace. [override virtual noexcept] QQmlEngine:: ~QQmlEngine Destroys the QQmlEngine. QScriptEngine myEngine; QScriptValue three = myEngine. MainWindow win; win. I have tried registering QTextCursor with qRegisterMetaType, but it doesn't help; Anyone can tell what I am doing wrong, and how to fix that? Many thanks. If you are using the Python logging module to can easily create a custom logging handler that passes the log messages through to a QPlainTextEdit instance (as described by Christopher). I also have to implement for cv::Mat type data. 2. Save yourself the hassle and use QStringList. Since Qt 5. A single QMetaObject instance is created for each QObject subclass that is used in an application, and this instance stores all the meta-information for the QObject subclass. Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered. Got a similar example working without explicitly calling qRegisterMetaType() just by removing the semicolon from the line Q_DECLARE_METATYPE(StateMachine::state) – user666412. Share. 1. I'm running the livox horizon lidar on one PC and running the loam on a different PC. 如果要使自定义类型或其他非QMetaType内置类型在QVaiant中使用，必须使用该宏Q_DECLARE_METATYPE。该类型必须有公有的 构造、析构、复制构造 函数 qRegisterMetaType 必须使用该函数的两种情况：1、如果非QMetaType内置类型要在 Qt 的属性系统中使用2、如果非QMetaType内置类型要在 queued 信号与槽 中使用。错误原因：. qRegisterMetaType<MyStruct>("MyStruct"); 若已经使用 Q_DECLARE_METATYPEQ 标记过该类型，可以使用其不带参数的版本： qRegisterMetaType<MyStruct>(); 同样的，若对象包含在自定义的命名空间中时，注册时要带上完整的命令空间，如： qRegisterMetaType<NSP::MyStruct>("NSP::MyStruct"); Note that for enum types, you no not even need to call qRegisterMetaType () in these cases. Note: This function is thread-safe. By implementing a factory it is possible to create custom QNetworkAccessManager with specialized caching, proxy and cookie support. The stretch factor changes the width of all characters in the font by factor percent. The connection in question is queued. Currently, on Linux and Android it is used for specifying connection to a server listening to a socket bound to an abstract address. Note that some registers are read-only registers. class QtGuiApplication : public QWidget { Q_OBJECT public: explicit QtGuiApplication (QWidget *parent = 0. Your code should look like this: Q_ENUM (StateEnum) //note the missing 'S' here Q_PROPERTY (StateEnum state READ state NOTIFY stateChanged) Share. Debugging signals and slots connections. {. I'll take your word on that, because on my rig fixing the return type of area() and providing the empty template parameter list for the specialization leaves only get() failing to compile, and as near as I can tell it may be because of the order this was pasted into the question. main. 这两个东西真难理清，不妨看看源码吧。. root - done ----> Histograms and ntuples are saved 1 event has been kept for refreshing and/or reviewing. cppWe will still need to register it with the meta-object system at run-time by calling the qRegisterMetaType() template function before we make any signal-slot connections that use this type. Even though we do not intend to use the type with QVariant in this example, it is good practice to also declare the new type with Q_DECLARE_METATYPE(). The following code: self. 0. Use Q_DECLARE_METATYPE (std::string) in one of your headers. (Make sure 'QVector<int>' is registered using qRegisterMetaType (). Here's the twist: this class is contained in a shared library, and therefore I want to avoid instructing anyone using my library to call qRegisterMetaType. Call qRegisterMetaType() to make type available to non-template based functions, such as the queued signal and slot connections. launch" and then "roslaunch velo2cam_calibration laser_pattern. (Parent is QTcpSocket (0x24a6ce8), parent's thread is ServiceSlots. QChildEvent. An alternative would be to wrap shared_ptr<int> in your own class and implement comparison the way you want. Note that if you intend to use the type in queued signal and slot connections or in QObject's property system, you also have to call qRegisterMetaType() since the names are resolved at runtime. 4 x64, and PyQt5 using its binary provided on riverbankcomputiong. qRegisterMetaType <rQJsonObject> ("rQJsonObject"); With this: no matching function for call to 'qRegisterMetaType'. Usually one puts this (note that the typedefed name is used as string argument): qRegisterMetaType < QSharedPointer < TestClass > > ( "SharedTestClass" );To use the type T in queued signal and slot connections, qRegisterMetaType() must be called before the first connection is established. . 如果要使自定义类型或其他非QMetaType内置类型在QVaiant中使用，必须使用该宏。. I tested your code on Qt 5. Here You need create this class object before use setContextProperty (). qRe terMetaType 是Qt框架中的一个函数，用于在Qt元对象系统中注册自定义的数据类型。. 0’ of a module called ‘com. When data values are exchanged between QML and C++, they are converted by the QML engine to have the correct data types as appropriate for use in QML or C++. hEvaluating Scripts. MyEnum needs to be registered with qRegisterMetaType. Detailed Description. Now the above code compiles and runs just fine. Note: If you want to use your custom metatypes also in queued slot connections or with QMetaMethod, you have to call qRegisterMetaType<QPushButton*>() Share. Fixed a Qt warning about "cannot queue arguments of type. qmlRegisterUncreatableType# qmlRegisterUncreatableType (pytype: type, uri: str, versionMajor. program exits if. Usually, we call the macro right below the class/struct declaration in the header file. int QMetaObject:: indexOfSignal (const char * signal) const.