Qt 4.8: QDeclarativeView Class Reference

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# QDeclarativeView Class Reference

The QDeclarativeView class provides a widget for displaying a Qt Declarative user interface. More...

     #include <QDeclarativeView>

Inherits: QGraphicsView.

This class was introduced in Qt 4.7.

- List of all members, including inherited members

## Public Types

enum | ResizeMode { SizeViewToRootObject, SizeRootObjectToView }
enum | Status { Null, Ready, Loading, Error }

## Properties

- resizeMode : ResizeMode
- source : QUrl
- status : const Status

- 13 properties inherited from QGraphicsView
- 2 properties inherited from QAbstractScrollArea
- 6 properties inherited from QFrame
- 58 properties inherited from QWidget
- 1 property inherited from QObject

## Public Functions

| QDeclarativeView ( QWidget * parent = 0 )
| QDeclarativeView ( const QUrl & source, QWidget * parent = 0 )
virtual | ~QDeclarativeView ()
QDeclarativeEngine * | engine () const
QList<QDeclarativeError> | errors () const
QSize | initialSize () const
ResizeMode | resizeMode () const
QDeclarativeContext * | rootContext () const
QGraphicsObject * | rootObject () const
void | setResizeMode ( ResizeMode )
void | setSource ( const QUrl & url )
QUrl | source () const
Status | status () const

- 77 public functions inherited from QGraphicsView
- 17 public functions inherited from QAbstractScrollArea
- 14 public functions inherited from QFrame
- 221 public functions inherited from QWidget
- 29 public functions inherited from QObject
- 13 public functions inherited from QPaintDevice

## Signals

void | sceneResized ( QSize size )
void | statusChanged ( QDeclarativeView::Status status )

- 1 signal inherited from QWidget
- 1 signal inherited from QObject

### Additional Inherited Members

- 3 public slots inherited from QGraphicsView
- 19 public slots inherited from QWidget
- 1 public slot inherited from QObject
- 4 static public members inherited from QWidget
- 7 static public members inherited from QObject
- 24 protected functions inherited from QGraphicsView
- 18 protected functions inherited from QAbstractScrollArea
- 3 protected functions inherited from QFrame
- 37 protected functions inherited from QWidget
- 8 protected functions inherited from QObject
- 1 protected function inherited from QPaintDevice
- 1 protected slot inherited from QGraphicsView
- 1 protected slot inherited from QAbstractScrollArea
- 1 protected slot inherited from QWidget

## Detailed Description

The QDeclarativeView class provides a widget for displaying a Qt Declarative user interface.

QDeclarativeItem objects can be placed on a standard QGraphicsScene and displayed with QGraphicsView. QDeclarativeView is a QGraphicsView subclass provided as a convenience for displaying QML files, and connecting between QML and C++ Qt objects.

QDeclarativeView provides:

- Management of QDeclarativeComponent loading and object creation
- Initialization of QGraphicsView for optimal performance with QML using these settings:
  - QGraphicsView::setOptimizationFlags(QGraphicsView::DontSavePainterState)
  - QGraphicsView::setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate)
  - QGraphicsScene::setItemIndexMethod(QGraphicsScene::NoIndex)
- Initialization of QGraphicsView for QML key handling using these settings:
  - QGraphicsView::viewport()->setFocusPolicy(Qt::NoFocus)
  - QGraphicsView::setFocusPolicy(Qt::StrongFocus)
  - QGraphicsScene::setStickyFocus(true)

Typical usage:

     QDeclarativeView *view = new QDeclarativeView;
     view->setSource(QUrl::fromLocalFile("myqmlfile.qml"));
     view->show();

Since QDeclarativeView is a QWidget-based class, it can be used to display QML interfaces within QWidget-based GUI applications that do not use the Graphics View framework.

To receive errors related to loading and executing QML with QDeclarativeView, you can connect to the statusChanged() signal and monitor for QDeclarativeView::Error. The errors are available via QDeclarativeView::errors().

If you're using your own QGraphicsScene-based scene with QDeclarativeView, remember to enable scene's sticky focus mode and to set itemIndexMethod to QGraphicsScene::NoIndex.

See also Integrating QML Code with Existing Qt UI Code and Using QML Bindings in C++ Applications.

## Member Type Documentation

### enum QDeclarativeView::ResizeMode

This enum specifies how to resize the view.

Constant | Value | Description
--- | --- | ---
`QDeclarativeView::SizeViewToRootObject` | `0` | The view resizes with the root item in the QML.
`QDeclarativeView::SizeRootObjectToView` | `1` | The view will automatically resize the root item to the size of the view.

### enum QDeclarativeView::Status

Specifies the loading status of the QDeclarativeView.

Constant | Value | Description
--- | --- | ---
`QDeclarativeView::Null` | `0` | This QDeclarativeView has no source set.
`QDeclarativeView::Ready` | `1` | This QDeclarativeView has loaded and created the QML component.
`QDeclarativeView::Loading` | `2` | This QDeclarativeView is loading network data.
`QDeclarativeView::Error` | `3` | One or more errors has occurred. Call errors() to retrieve a list of errors.

## Property Documentation

### resizeMode : ResizeMode

This property holds whether the view should resize the canvas contents.

If this property is set to SizeViewToRootObject (the default), the view resizes with the root item in the QML.

If this property is set to SizeRootObjectToView, the view will automatically resize the root item.

Regardless of this property, the sizeHint of the view is the initial size of the root item. Note though that since QML may load dynamically, that size may change.

Access functions:

ResizeMode | resizeMode () const
void | setResizeMode ( ResizeMode )

### source : QUrl

This property holds the URL of the source of the QML component.

Changing this property causes the QML component to be reloaded.

Ensure that the URL provided is full and correct, in particular, use QUrl::fromLocalFile() when loading a file from the local filesystem.

Access functions:

QUrl | source () const
void | setSource ( const QUrl & url )

See also Loading Resources in QML.

### status : const Status

The component's current status.

Access functions:

Status | status () const

Notifier signal:

void | statusChanged ( QDeclarativeView::Status status )

## Member Function Documentation

### QDeclarativeView::QDeclarativeView ( QWidget * parent = 0 )

Constructs a QDeclarativeView with the given parent.

### QDeclarativeView::QDeclarativeView ( const QUrl & source, QWidget * parent = 0 )

Constructs a QDeclarativeView with the given QML source and parent.

### QDeclarativeView::~QDeclarativeView ()`[virtual]`

Destroys the view.

### QDeclarativeEngine * QDeclarativeView::engine () const

Returns a pointer to the QDeclarativeEngine used for instantiating QML Components.

### QList<QDeclarativeError> QDeclarativeView::errors () const

Return the list of errors that occurred during the last compile or create operation. When the status is not Error, an empty list is returned.

### QSize QDeclarativeView::initialSize () const

Returns the initial size of the root object

### QDeclarativeContext * QDeclarativeView::rootContext () const

This function returns the root of the context hierarchy. Each QML component is instantiated in a QDeclarativeContext. QDeclarativeContext's are essential for passing data to QML components. In QML, contexts are arranged hierarchically and this hierarchy is managed by the QDeclarativeEngine.

### QGraphicsObject * QDeclarativeView::rootObject () const

Returns the view's root item.

### void QDeclarativeView::sceneResized ( QSize size )`[signal]`

This signal is emitted when the view is resized to size.

### void QDeclarativeView::statusChanged ( QDeclarativeView::Status status )`[signal]`

This signal is emitted when the component's current status changes.