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QDeclarativeComponent Class Reference
[QtDeclarative module]

The QDeclarativeComponent class encapsulates a QML component description. More...

 #include <QDeclarativeComponent>

Inherits QObject.

This class was introduced in Qt 4.7.


Public Types

enum Status { Null, Ready, Loading, Error }

Properties


Public Functions

QDeclarativeComponent ( QDeclarativeEngine * engine, QObject * parent = 0 )
QDeclarativeComponent ( QDeclarativeEngine * engine, const QString & fileName, QObject * parent = 0 )
QDeclarativeComponent ( QDeclarativeEngine * engine, const QUrl & url, QObject * parent = 0 )
virtual ~QDeclarativeComponent ()
virtual QObject * beginCreate ( QDeclarativeContext * context )
virtual void completeCreate ()
virtual QObject * create ( QDeclarativeContext * context = 0 )
QDeclarativeContext * creationContext () const
QList<QDeclarativeError> errors () const
bool isError () const
bool isLoading () const
bool isNull () const
bool isReady () const
void loadUrl ( const QUrl & url )
qreal progress () const
void setData ( const QByteArray & data, const QUrl & url )
Status status () const
QUrl url () const

Signals

void progressChanged ( qreal progress )
void statusChanged ( QDeclarativeComponent::Status status )

Additional Inherited Members


Detailed Description

The QDeclarativeComponent class encapsulates a QML component description.


Member Type Documentation

enum QDeclarativeComponent::Status

Specifies the loading status of the QDeclarativeComponent.

ConstantValueDescription
QDeclarativeComponent::Null0This QDeclarativeComponent has no data. Call loadUrl() or setData() to add QML content.
QDeclarativeComponent::Ready1This QDeclarativeComponent is ready and create() may be called.
QDeclarativeComponent::Loading2This QDeclarativeComponent is loading network data.
QDeclarativeComponent::Error3An error has occured. Calling errorDescription() to retrieve a description.


Property Documentation

isError : const bool

Is true if the component is in the Error state, false otherwise.

Equivalent to status() == QDeclarativeComponent::Error.

Access functions:

bool isError () const

Notifier signal:

void statusChanged ( QDeclarativeComponent::Status status )

isLoading : const bool

Is true if the component is in the Loading state, false otherwise.

Equivalent to status() == QDeclarativeComponent::Loading.

Access functions:

bool isLoading () const

Notifier signal:

void statusChanged ( QDeclarativeComponent::Status status )

isNull : const bool

Is true if the component is in the Null state, false otherwise.

Equivalent to status() == QDeclarativeComponent::Null.

Access functions:

bool isNull () const

Notifier signal:

void statusChanged ( QDeclarativeComponent::Status status )

isReady : const bool

Is true if the component is in the Ready state, false otherwise.

Equivalent to status() == QDeclarativeComponent::Ready.

Access functions:

bool isReady () const

Notifier signal:

void statusChanged ( QDeclarativeComponent::Status status )

progress : const qreal

The progress of loading the component, from 0.0 (nothing loaded) to 1.0 (finished).

Access functions:

qreal progress () const

Notifier signal:

void progressChanged ( qreal progress )

status : const Status

The component's current status.

Access functions:

Status status () const

Notifier signal:

void statusChanged ( QDeclarativeComponent::Status status )

url : const QUrl

The component URL. This is the URL passed to either the constructor, or the loadUrl() or setData() methods.

Access functions:

QUrl url () const

Member Function Documentation

QDeclarativeComponent::QDeclarativeComponent ( QDeclarativeEngine * engine, QObject * parent = 0 )

Create a QDeclarativeComponent with no data and give it the specified engine and parent. Set the data with setData().

QDeclarativeComponent::QDeclarativeComponent ( QDeclarativeEngine * engine, const QString & fileName, QObject * parent = 0 )

Create a QDeclarativeComponent from the given fileName and give it the specified parent and engine.

See also loadUrl().

QDeclarativeComponent::QDeclarativeComponent ( QDeclarativeEngine * engine, const QUrl & url, QObject * parent = 0 )

Create a QDeclarativeComponent from the given url and give it the specified parent and engine.

See also loadUrl().

QDeclarativeComponent::~QDeclarativeComponent ()   [virtual]

Destruct the QDeclarativeComponent.

QObject * QDeclarativeComponent::beginCreate ( QDeclarativeContext * context )   [virtual]

This method provides more advanced control over component instance creation. In general, programmers should use QDeclarativeComponent::create() to create a component.

Create an object instance from this component. Returns 0 if creation failed. context specifies the context within which to create the object instance.

When QDeclarativeComponent constructs an instance, it occurs in three steps:

  1. The object hierarchy is created, and constant values are assigned.
  2. Property bindings are evaluated for the the first time.
  3. If applicable, QDeclarativeParserStatus::componentComplete() is called on objects.

QDeclarativeComponent::beginCreate() differs from QDeclarativeComponent::create() in that it only performs step 1. QDeclarativeComponent::completeCreate() must be called to complete steps 2 and 3.

This breaking point is sometimes useful when using attached properties to communicate information to an instantiated component, as it allows their initial values to be configured before property bindings take effect.

void QDeclarativeComponent::completeCreate ()   [virtual]

This method provides more advanced control over component instance creation. In general, programmers should use QDeclarativeComponent::create() to create a component.

Complete a component creation begin with QDeclarativeComponent::beginCreate().

QObject * QDeclarativeComponent::create ( QDeclarativeContext * context = 0 )   [virtual]

Create an object instance from this component. Returns 0 if creation failed. context specifies the context within which to create the object instance.

If context is 0 (the default), it will create the instance in the engine' s root context.

QDeclarativeContext * QDeclarativeComponent::creationContext () const

Returns the QDeclarativeContext the component was created in. This is only valid for components created directly from QML.

QList<QDeclarativeError> QDeclarativeComponent::errors () const

Return the list of errors that occured during the last compile or create operation. An empty list is returned if isError() is not set.

void QDeclarativeComponent::loadUrl ( const QUrl & url )

Load the QDeclarativeComponent from the provided url.

void QDeclarativeComponent::progressChanged ( qreal progress )   [signal]

Emitted whenever the component's loading progress changes. progress will be the current progress between 0.0 (nothing loaded) and 1.0 (finished).

void QDeclarativeComponent::setData ( const QByteArray & data, const QUrl & url )

Sets the QDeclarativeComponent to use the given QML data. If url is provided, it is used to set the component name and to provide a base path for items resolved by this component.

void QDeclarativeComponent::statusChanged ( QDeclarativeComponent::Status status )   [signal]

Emitted whenever the component's status changes. status will be the new status.


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Qt 4.7.0