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Internal/Contributor docs for the Qt SDK. <b>Note:</b> These are NOT official API docs; those are found <a href='https://doc.qt.io/'>here</a>.
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Public Slots | Signals | Public Member Functions | List of all members
QQuickImageResponse Class Referenceabstract

The QQuickImageResponse class provides an interface for asynchronous image loading in QQuickAsyncImageProvider. \inmodule QtQuick. More...

#include <qquickimageprovider.h>

+ Inheritance diagram for QQuickImageResponse:
+ Collaboration diagram for QQuickImageResponse:

Public Slots

virtual void cancel ()
 This method is used to communicate that the response is no longer required by the engine.
 
- Public Slots inherited from QObject
void deleteLater ()
 \threadsafe
 

Signals

void finished ()
 Signals that the job execution has finished (be it successfully, because an error happened or because it was cancelled).
 
- Signals inherited from QObject
void destroyed (QObject *=nullptr)
 This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
 
void objectNameChanged (const QString &objectName, QPrivateSignal)
 This signal is emitted after the object's name has been changed.
 

Public Member Functions

 QQuickImageResponse ()
 Constructs the image response.
 
 ~QQuickImageResponse () override
 Destructs the image response.
 
virtual QQuickTextureFactory * textureFactory () const =0
 Returns the texture factory for the job.
 
virtual QString errorString () const
 Returns the error string for the job execution.
 
- Public Member Functions inherited from QObject
Q_INVOKABLE QObject (QObject *parent=nullptr)
 Constructs an object with parent object parent.
 
virtual ~QObject ()
 Destroys the object, deleting all its child objects.
 
virtual bool event (QEvent *event)
 This virtual function receives events to an object and should return true if the event e was recognized and processed.
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 Filters events if this object has been installed as an event filter for the watched object.
 
QString objectName () const
 
Q_WEAK_OVERLOAD void setObjectName (const QString &name)
 Sets the object's name to name.
 
void setObjectName (QAnyStringView name)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
QBindable< QString > bindableObjectName ()
 
bool isWidgetType () const
 Returns true if the object is a widget; otherwise returns false.
 
bool isWindowType () const
 Returns true if the object is a window; otherwise returns false.
 
bool isQuickItemType () const
 Returns true if the object is a QQuickItem; otherwise returns false.
 
bool signalsBlocked () const noexcept
 Returns true if signals are blocked; otherwise returns false.
 
bool blockSignals (bool b) noexcept
 If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
 
QThread * thread () const
 Returns the thread in which the object lives.
 
bool moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
 Changes the thread affinity for this object and its children and returns true on success.
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
 
int startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
 
void killTimer (int id)
 Kills the timer with timer identifier, id.
 
void killTimer (Qt::TimerId id)
 
template<typename T >
T findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
 
template<typename T >
QList< T > findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
 
template<typename T >
T findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
template<typename T >
QList< T > findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QObjectList & children () const
 Returns a list of child objects.
 
void setParent (QObject *parent)
 Makes the object a child of parent.
 
void installEventFilter (QObject *filterObj)
 Installs an event filter filterObj on this object.
 
void removeEventFilter (QObject *obj)
 Removes an event filter object obj from this object.
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
 
bool disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
 
bool disconnect (const QObject *receiver, const char *member=nullptr) const
 
void dumpObjectTree () const
 Dumps a tree of children to the debug output.
 
void dumpObjectInfo () const
 Dumps information about signal connections, etc.
 
bool setProperty (const char *name, const QVariant &value)
 Sets the value of the object's name property to value.
 
bool setProperty (const char *name, QVariant &&value)
 
QVariant property (const char *name) const
 Returns the value of the object's name property.
 
QList< QByteArray > dynamicPropertyNames () const
 
QBindingStorage * bindingStorage ()
 
const QBindingStorage * bindingStorage () const
 
QObject * parent () const
 Returns a pointer to the parent object.
 
bool inherits (const char *classname) const
 Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.
 

Additional Inherited Members

- Static Public Member Functions inherited from QObject
static QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
 \threadsafe
 
static QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
 
static bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
 \threadsafe
 
static bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
 
static bool disconnect (const QMetaObject::Connection &)
 Disconnect a connection.
 
template<typename Func1 , typename Func2 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
 
template<typename Func1 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)
 
- Protected Member Functions inherited from QObject
QObject * sender () const
 Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
 
int senderSignalIndex () const
 
int receivers (const char *signal) const
 Returns the number of receivers connected to the signal.
 
bool isSignalConnected (const QMetaMethod &signal) const
 
virtual void timerEvent (QTimerEvent *event)
 This event handler can be reimplemented in a subclass to receive timer events for the object.
 
virtual void childEvent (QChildEvent *event)
 This event handler can be reimplemented in a subclass to receive child events.
 
virtual void customEvent (QEvent *event)
 This event handler can be reimplemented in a subclass to receive custom events.
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
 QObject (QObjectPrivate &dd, QObject *parent=nullptr)
 
- Protected Attributes inherited from QObject
QScopedPointer< QObjectData > d_ptr
 
- Properties inherited from QObject
QString objectName
 the name of this object
 
- Related Symbols inherited from QObject
 Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
 
 
 
 \macro Q_CLASSINFO(Name, Value)
 

Detailed Description

The QQuickImageResponse class provides an interface for asynchronous image loading in QQuickAsyncImageProvider. \inmodule QtQuick.

Since
5.6

The purpose of an image response is to provide a way for image provider jobs to be executed in an asynchronous way.

Responses are deleted via \l deleteLater once the finished() signal has been emitted. If you are using QRunnable as base for your QQuickImageResponse ensure automatic deletion is disabled.

See the \l {imageresponseprovider}{Image Response Provider Example} for a complete implementation.

See also
QQuickImageProvider

Definition at line 38 of file qquickimageprovider.h.

Constructor & Destructor Documentation

◆ QQuickImageResponse()

QQuickImageResponse::QQuickImageResponse ( )

Constructs the image response.

Definition at line 129 of file qquickimageprovider.cpp.

References finished(), qmlobject_connect, SIGNAL, and SLOT.

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◆ ~QQuickImageResponse()

QQuickImageResponse::~QQuickImageResponse ( )
override

Destructs the image response.

Definition at line 139 of file qquickimageprovider.cpp.

Member Function Documentation

◆ cancel

void QQuickImageResponse::cancel ( )
virtualslot

This method is used to communicate that the response is no longer required by the engine.

It may be reimplemented to cancel a request in the provider side, however, it is not mandatory.

A cancelled QQuickImageResponse still needs to emit finished() so that the engine may clean up the QQuickImageResponse.

Note
finished() should not be emitted until the response is complete, regardless of whether or not cancel() was called. If it is called prematurely, the engine may destroy the response while it is still active, leading to a crash.

Definition at line 163 of file qquickimageprovider.cpp.

◆ errorString()

QString QQuickImageResponse::errorString ( ) const
virtual

Returns the error string for the job execution.

An empty string means no error.

Reimplemented in SharedTextureImageResponse, and SharedTextureImageResponse.

Definition at line 146 of file qquickimageprovider.cpp.

◆ finished

void QQuickImageResponse::finished ( )
signal

Signals that the job execution has finished (be it successfully, because an error happened or because it was cancelled).

Note
Emission of this signal must be the final action the response performs: once the signal is received, the response will subsequently be destroyed by the engine.

Referenced by QQuickImageResponse(), SharedTextureImageResponse::doResponse(), and SharedTextureImageResponse::doResponse().

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◆ textureFactory()

QQuickTextureFactory * QQuickImageResponse::textureFactory ( ) const
pure virtual

Returns the texture factory for the job.

You can use QQuickTextureFactory::textureFactoryForImage if your provider works with QImage. The engine takes ownership of the returned QQuickTextureFactory.

Note
This method will be called only when needed. For example, it may not be called if there is an error or the job is cancelled. Therefore, allocate the QQuickTextureFactory instance only in this method or otherwise ensure its deletion.

Implemented in SharedTextureImageResponse, and SharedTextureImageResponse.

The documentation for this class was generated from the following files: