PySide6.QtCore.QMetaObject

class QMetaObject

The QMetaObject class contains meta-information about Qt objects.

Details

The Qt Meta-Object System in Qt is responsible for the signals and slots inter-object communication mechanism, runtime type information, and the Qt property system. 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. This object is available as metaObject() .

This class is not normally required for application programming, but it is useful if you write meta-applications, such as scripting engines or GUI builders.

The functions you are most likely to find useful are these:

The index functions indexOfConstructor() , indexOfMethod() , indexOfEnumerator() , and indexOfProperty() map names of constructors, member functions, enumerators, or properties to indexes in the meta-object. For example, Qt uses indexOfMethod() internally when you connect a signal to a slot.

Classes can also have a list of name–value pairs of additional class information, stored in QMetaClassInfo objects. The number of pairs is returned by classInfoCount() , single pairs are returned by classInfo() , and you can search for pairs with indexOfClassInfo() .

Note

Operations that use the meta object system are generally thread- safe, as QMetaObjects are typically static read-only instances generated at compile time. However, if meta objects are dynamically modified by the application (for instance, when using QQmlPropertyMap), then the application has to explicitly synchronize access to the respective meta object.

See also

QMetaClassInfo QMetaEnum QMetaMethod QMetaProperty QMetaType Meta-Object System

Synopsis

Methods

Static functions

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

class Call
__repr__()
Return type:

str

cast(obj)
Parameters:

obj – QObject

Return type:

QObject

cast(obj)
Parameters:

obj – QObject

Return type:

QObject

static checkConnectArgs(signal, method)
Parameters:
Return type:

bool

Returns true if the signal and method arguments are compatible; otherwise returns false.

static checkConnectArgs(signal, method)
Parameters:

  • signal – str

  • method – str

Return type:

bool

Returns true if the signal and method arguments are compatible; otherwise returns false.

Both signal and method are expected to be normalized.

classInfo(index)
Parameters:

index – int

Return type:

QMetaClassInfo

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Returns the meta-data for the item of class information with the given index.

Example:

class MyClass(QObject):

    Q_OBJECT
    Q_CLASSINFO("author", "Sabrina Schweinsteiger")
    Q_CLASSINFO("url", "http://doc.moosesoft.co.uk/1.0/")
# public
    ...

See also

classInfoCount() classInfoOffset() indexOfClassInfo()

classInfoCount()
Return type:

int

Returns the number of items of class information in this class.

classInfoOffset()
Return type:

int

Returns the class information offset for this class; i.e. the index position of this class’s first class information item.

If the class has no superclasses with class information, the offset is 0; otherwise the offset is the sum of all the class information items in the class’s superclasses.

className()
Return type:

str

Returns the class name.

See also

superClass()

static connectSlotsByName(o)
Parameters:

o – QObject

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Searches recursively for all child objects of the given object, and connects matching signals from them to slots of object that follow the following form:

on_<object = void(<signal parameters>)

Let’s assume our object has a child object of type QPushButton with the object name button1. The slot to catch the button’s clicked() signal would be:

def on_button1_clicked():

If object itself has a properly set object name, its own signals are also connected to its respective slots.

See also

setObjectName()

constructor(index)
Parameters:

index – int

Return type:

QMetaMethod

Returns the meta-data for the constructor with the given index.

constructorCount()
Return type:

int

Returns the number of constructors in this class.

static disconnect(sender, signal_index, receiver, method_index)
Parameters:

  • sender – QObject

  • signal_index – int

  • receiver – QObject

  • method_index – int

Return type:

bool

static disconnectOne(sender, signal_index, receiver, method_index)
Parameters:

  • sender – QObject

  • signal_index – int

  • receiver – QObject

  • method_index – int

Return type:

bool

enumerator(index)
Parameters:

index – int

Return type:

QMetaEnum

Returns the meta-data for the enumerator with the given index.

enumeratorCount()
Return type:

int

Returns the number of enumerators in this class.

enumeratorOffset()
Return type:

int

Returns the enumerator offset for this class; i.e. the index position of this class’s first enumerator.

If the class has no superclasses with enumerators, the offset is 0; otherwise the offset is the sum of all the enumerators in the class’s superclasses.

indexOfClassInfo(name)
Parameters:

name – str

Return type:

int

Finds class information item name and returns its index; otherwise returns -1.

indexOfConstructor(constructor)
Parameters:

constructor – str

Return type:

int

Finds constructor and returns its index; otherwise returns -1.

Note that the constructor has to be in normalized form, as returned by normalizedSignature() .

indexOfEnumerator(name)
Parameters:

name – str

Return type:

int

Finds enumerator name and returns its index; otherwise returns -1.

indexOfMethod(method)
Parameters:

method – str

Return type:

int

Finds method and returns its index; otherwise returns -1.

Note that the method has to be in normalized form, as returned by normalizedSignature() .

indexOfProperty(name)
Parameters:

name – str

Return type:

int

Finds property name and returns its index; otherwise returns -1.

indexOfSignal(signal)
Parameters:

signal – str

Return type:

int

Finds signal and returns its index; otherwise returns -1.

This is the same as indexOfMethod() , except that it will return -1 if the method exists but isn’t a signal.

Note that the signal has to be in normalized form, as returned by normalizedSignature() .

indexOfSlot(slot)
Parameters:

slot – str

Return type:

int

Finds slot and returns its index; otherwise returns -1.

This is the same as indexOfMethod() , except that it will return -1 if the method exists but isn’t a slot.

inherits(metaObject)
Parameters:

metaObject – QMetaObject

Return type:

bool

Returns true if the class described by this QMetaObject inherits the type described by metaObject; otherwise returns false.

A type is considered to inherit itself.

static invokeMethod(obj, member, val0[, val1=QGenericArgument()[, val2=QGenericArgument()[, val3=QGenericArgument()[, val4=QGenericArgument()[, val5=QGenericArgument()[, val6=QGenericArgument()[, val7=QGenericArgument()[, val8=QGenericArgument()[, val9=QGenericArgument()]]]]]]]]])
Parameters:
Return type:

bool

Please use the variadic overload of this function.

This overload invokes the member using the connection type AutoConnection and ignores return values.

static invokeMethod(object, member[, val0={}[, val1={}[, val2={}[, val3={}[, val4={}[, val5={}[, val6={}[, val7={}[, val8={}[, val9={}]]]]]]]]]])
Parameters:

  • object – QObject

  • member – str

  • val0 – QGenericArgumentHolder

  • val1 – QGenericArgumentHolder

  • val2 – QGenericArgumentHolder

  • val3 – QGenericArgumentHolder

  • val4 – QGenericArgumentHolder

  • val5 – QGenericArgumentHolder

  • val6 – QGenericArgumentHolder

  • val7 – QGenericArgumentHolder

  • val8 – QGenericArgumentHolder

  • val9 – QGenericArgumentHolder

Return type:

bool

static invokeMethod(obj, member, ret[, val0=QGenericArgument(nullptr)[, val1=QGenericArgument()[, val2=QGenericArgument()[, val3=QGenericArgument()[, val4=QGenericArgument()[, val5=QGenericArgument()[, val6=QGenericArgument()[, val7=QGenericArgument()[, val8=QGenericArgument()[, val9=QGenericArgument()]]]]]]]]]])
Parameters:
Return type:

bool

Please use the variadic overload of this function.

This overload always invokes the member using the connection type AutoConnection .

static invokeMethod(obj, member, type, val0[, val1=QGenericArgument()[, val2=QGenericArgument()[, val3=QGenericArgument()[, val4=QGenericArgument()[, val5=QGenericArgument()[, val6=QGenericArgument()[, val7=QGenericArgument()[, val8=QGenericArgument()[, val9=QGenericArgument()]]]]]]]]])
Parameters:
Return type:

bool

Please use the variadic overload of this function.

This overload can be used if the return value of the member is of no interest.

static invokeMethod(object, member, type[, val0={}[, val1={}[, val2={}[, val3={}[, val4={}[, val5={}[, val6={}[, val7={}[, val8={}[, val9={}]]]]]]]]]])
Parameters:

  • object – QObject

  • member – str

  • type – ConnectionType

  • val0 – QGenericArgumentHolder

  • val1 – QGenericArgumentHolder

  • val2 – QGenericArgumentHolder

  • val3 – QGenericArgumentHolder

  • val4 – QGenericArgumentHolder

  • val5 – QGenericArgumentHolder

  • val6 – QGenericArgumentHolder

  • val7 – QGenericArgumentHolder

  • val8 – QGenericArgumentHolder

  • val9 – QGenericArgumentHolder

Return type:

bool

static invokeMethod(object, member, ret[, val0={}[, val1={}[, val2={}[, val3={}[, val4={}[, val5={}[, val6={}[, val7={}[, val8={}[, val9={}]]]]]]]]]])
Parameters:

  • object – QObject

  • member – str

  • ret – QGenericReturnArgumentHolder

  • val0 – QGenericArgumentHolder

  • val1 – QGenericArgumentHolder

  • val2 – QGenericArgumentHolder

  • val3 – QGenericArgumentHolder

  • val4 – QGenericArgumentHolder

  • val5 – QGenericArgumentHolder

  • val6 – QGenericArgumentHolder

  • val7 – QGenericArgumentHolder

  • val8 – QGenericArgumentHolder

  • val9 – QGenericArgumentHolder

Return type:

object

static invokeMethod(obj, member, type, ret[, val0=QGenericArgument(nullptr)[, val1=QGenericArgument()[, val2=QGenericArgument()[, val3=QGenericArgument()[, val4=QGenericArgument()[, val5=QGenericArgument()[, val6=QGenericArgument()[, val7=QGenericArgument()[, val8=QGenericArgument()[, val9=QGenericArgument()]]]]]]]]]])
Parameters:
Return type:

bool

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Please use the variadic overload of this function

Invokes the member (a signal or a slot name) on the object obj. Returns true if the member could be invoked. Returns false if there is no such member or the parameters did not match.

See the variadic invokeMethod() function for more information. This function should behave the same way as that one, with the following limitations:

  • The number of parameters is limited to 10.

  • Parameter names may need to be an exact string match.

  • Meta types are not automatically registered.

With asynchronous method invocations, the parameters must be of types that are already known to Qt’s meta-object system, because Qt needs to copy the arguments to store them in an event behind the scenes. If you try to use a queued connection and get the error message

QMetaObject.invokeMethod: Unable to handle unregistered datatype 'MyType'

call qRegisterMetaType() to register the data type before you call invokeMethod() .

See also

Q_ARG() Q_RETURN_ARG() qRegisterMetaType() invoke()

static invokeMethod(object, member, type, ret[, val0={}[, val1={}[, val2={}[, val3={}[, val4={}[, val5={}[, val6={}[, val7={}[, val8={}[, val9={}]]]]]]]]]])
Parameters:

  • object – QObject

  • member – str

  • type – ConnectionType

  • ret – QGenericReturnArgumentHolder

  • val0 – QGenericArgumentHolder

  • val1 – QGenericArgumentHolder

  • val2 – QGenericArgumentHolder

  • val3 – QGenericArgumentHolder

  • val4 – QGenericArgumentHolder

  • val5 – QGenericArgumentHolder

  • val6 – QGenericArgumentHolder

  • val7 – QGenericArgumentHolder

  • val8 – QGenericArgumentHolder

  • val9 – QGenericArgumentHolder

Return type:

object

metaType()
Return type:

QMetaType

Returns the metatype corresponding to this metaobject. If the metaobject originates from a namespace, an invalid metatype is returned.

method(index)
Parameters:

index – int

Return type:

QMetaMethod

Returns the meta-data for the method with the given index.

methodCount()
Return type:

int

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Returns the number of methods in this class, including the number of methods provided by each base class. These include signals and slots as well as normal member functions.

Use code like the following to obtain a QStringList containing the methods specific to a given class:

QMetaObject* metaObject = obj.metaObject()
methods = QStringList()
for i in range(metaObject.methodOffset(), metaObject.methodCount()):
    methods << QString.fromLatin1(metaObject.method(i).methodSignature())

See also

method() methodOffset() indexOfMethod()

methodOffset()
Return type:

int

Returns the method offset for this class; i.e. the index position of this class’s first member function.

The offset is the sum of all the methods in the class’s superclasses (which is always positive since QObject has the deleteLater() slot and a destroyed() signal).

newInstance(val0[, val1=QGenericArgument()[, val2=QGenericArgument()[, val3=QGenericArgument()[, val4=QGenericArgument()[, val5=QGenericArgument()[, val6=QGenericArgument()[, val7=QGenericArgument()[, val8=QGenericArgument()[, val9=QGenericArgument()]]]]]]]]])
Parameters:
Return type:

QObject

Please use the variadic overload of this function

Constructs a new instance of this class. You can pass up to ten arguments (val0, val1, val2, val3, val4, val5, val6, val7, val8, and val9) to the constructor. Returns the new object, or None if no suitable constructor is available.

Note that only constructors that are declared with the Q_INVOKABLE modifier are made available through the meta-object system.

See also

Q_ARG() constructor()

static normalizedSignature(method)
Parameters:

method – str

Return type:

QByteArray

Normalizes the signature of the given method.

Qt uses normalized signatures to decide whether two given signals and slots are compatible. Normalization reduces whitespace to a minimum, moves ‘const’ to the front where appropriate, removes ‘const’ from value types and replaces const references with values.

static normalizedType(type)
Parameters:

type – str

Return type:

QByteArray

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Normalizes a type.

See normalizedSignature() for a description on how Qt normalizes.

Example:

normType = QMetaObject.normalizedType(" int *")
# normType is now "const int*"

See also

normalizedSignature()

property(index)
Parameters:

index – int

Return type:

QMetaProperty

Returns the meta-data for the property with the given index. If no such property exists, a null QMetaProperty is returned.

propertyCount()
Return type:

int

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Returns the number of properties in this class, including the number of properties provided by each base class.

Use code like the following to obtain a QStringList containing the properties specific to a given class:

QMetaObject* metaObject = obj.metaObject()
properties = QStringList()
for i in range(metaObject.propertyOffset(), metaObject.propertyCount()):
    properties << QString.fromLatin1(metaObject.property(i).name())

See also

property() propertyOffset() indexOfProperty()

propertyOffset()
Return type:

int

Returns the property offset for this class; i.e. the index position of this class’s first property.

The offset is the sum of all the properties in the class’s superclasses (which is always positive since QObject has the objectName property).

superClass()
Return type:

QMetaObject

Returns the meta-object of the superclass, or None if there is no such object.

See also

className()

userProperty()
Return type:

QMetaProperty

Returns the property that has the USER flag set to true.

See also

isUser()

class Connection

Synopsis

Methods

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description

Represents a handle to a signal-slot (or signal-functor) connection.

It can be used to check if the connection is valid and to disconnect it using disconnect() . For a signal-functor connection without a context object, it is the only way to selectively disconnect that connection.

As Connection is just a handle, the underlying signal-slot connection is unaffected when Connection is destroyed or reassigned.

__init__()

Creates a Connection instance.

__init__(other)
Parameters:

other – Connection

Create a copy of the handle to the other connection

swap(other)
Parameters:

other – Connection

Swaps this Connection instance with other. This operation is very fast and never fails.