Since: BlackBerry 10.0.0

#include <bb/cascades/ResourceTracker>

Abstract base class inherited by all resource trackers.

A resource tracker is used to access the asynchronous features of resources, such as the state. All resources have a state that can be accessed, but some resources (for example, Image) also have details about the size which can be accessed. Trackers also have signals that are emitted when a state or other property is updated.

See also:




QML properties

state: bb::cascades::ResourceState::Type [read-only]
objectName: QStringInherited
parent: QObject [read-only]Inherited

QML signals

onStateChanged: {}
onCreationCompletedInherited: {}
onObjectNameChangedInherited: {}

Properties Index

bb::cascades::ResourceState::Typestate [read-only]
QObjectparent [read-only]Inherited

Public Functions Index

virtual ~ResourceTracker ()
Q_INVOKABLE boolhasErrors () const
bb::cascades::ResourceState::Typestate () const
voidsetObjectName (const QString &name)Inherited
virtual Q_INVOKABLE QStringtoDebugString () const Inherited

Protected Functions Index

Only has inherited protected functions

BaseObject (QObject *parent=0)Inherited

Signals Index

voidstateChanged (bb::cascades::ResourceState::Type newState)
voidcreationCompleted ()Inherited
voidobjectNameChanged (const QString &objectName)Inherited


bb::cascades::ResourceState::Type state[read-only]

The current state for the resource.

Default state is Unknown.

When the state changes, the stateChanged() signal will be emitted.


BlackBerry 10.0.0

QString objectNameInherited

This property is overridden from QObject.

As the objectName property is overridden from the QObject class, this signal will not be emitted if setObjectName() function is called directly on QObject.

The default value of this property is QString::null.

See also:



BlackBerry 10.0.0

QObject parentInherited[read-only]

A read-only property that represents this object's parent.

The parent of an object is specified using QObject::setParent(QObject*). The purpose of the property is to expose the object's parent to QML.

This property is read-only to prevent modifications from QML, where typically the parent is declaratively set. In C++ code, the parent can be explicitly set using QObject::setParent(QObject*), or implicitly set by adding it to a visual container.

The default value of this property is 0.


BlackBerry 10.0.0

Public Functions

virtual~ResourceTracker ()


Q_INVOKABLE bool hasErrors ()

Determines whether the resource is in one of the error states.


true if the image is in any error state, false otherwise.

See also:



BlackBerry 10.0.0

bb::cascades::ResourceState::Type state ()

Returns the current resource state.


Current resource state.


BlackBerry 10.0.0

void setObjectName (Inherited

Sets the objectName property.


The new name for the object.


BlackBerry 10.0.0

virtual Q_INVOKABLE QString toDebugString ()Inherited

Returns a debug string representing this object.


A debug string for the object.


BlackBerry 10.0.0

Protected Functions

(Only has inherited protected functions)

BaseObject (Inherited

Constructs an instance of BaseObject's subclass.


An optional parent, defaults to 0.


BlackBerry 10.0.0


void stateChanged (

Emitted when the state is changed for this resource.


Due to a work around for a Qt Core issue with accessing enums from QML, the argument of this signal doesn't follow naming convention for signals in which the signal arguments are typically named to match the associated property's name. Use the object's property to access current property value instead of the signal argument to avoid runtime errors (i.e. use state instead of newState).


The new state.


BlackBerry 10.0.0

void creationCompleted ()Inherited

This signal is emitted only when this object is instantiated as a result of loading a QML document and creating the root node, or when an object is being constructed using its builder class.

This signal is emitted only when this object is instantiated as a result of loading a QML document and creating the root node (only after the root component that caused this instantiation has completed construction), or when the object is being constructed from its builder class. This signal is emitted to indicate that the construction and initialization of the object has been completed, the properties are initialized, and any QML binding values have been assigned to the object.

This signal is not emitted when the object is constructed from C++ using the constructor. If the object is constructed using its builder class, the signal is emitted when the the builder class returns the fully constructed object.

This signal can be used when there is an activity that needs to be performed, such as a property state integrity verification after the object is instantiated from a QML document or a builder, but before control is returned to the application.

See also:



BlackBerry 10.0.0

void objectNameChanged (Inherited

This signal is emitted when the objectName property is changed.


BlackBerry 10.0.0

Last modified: 2014-03-13

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