MeeGo 1.2 Harmattan Developer Documentation Develop for the Nokia N9

Contents

QGalleryAbstractRequest Class Reference

The QGalleryAbstractRequest class provides a base class for gallery requests. More...

 #include <QGalleryAbstractRequest>

Inherits: QObject.

Inherited by: QGalleryItemRequest, QGalleryQueryRequest, and QGalleryTypeRequest.

This class was introduced in Qt Mobility 1.1.

Public Types

enum RequestError { NoError, NoGallery, NotSupported, GalleryError }
enum RequestType { QueryRequest, ItemRequest, TypeRequest }
enum State { Inactive, Active, Canceling, Canceled, ..., Error }

Properties

  • 1 property inherited from QObject

Public Functions

QGalleryAbstractRequest ( RequestType type, QObject * parent = 0 )
QGalleryAbstractRequest ( QAbstractGallery * gallery, RequestType type, QObject * parent = 0 )
~QGalleryAbstractRequest ()
int currentProgress () const
int error () const
QString errorString () const
QAbstractGallery * gallery () const
bool isSupported () const
int maximumProgress () const
void setGallery ( QAbstractGallery * gallery )
State state () const
RequestType type () const
bool waitForFinished ( int msecs )
  • 29 public functions inherited from QObject

Public Slots

void cancel ()
void clear ()
void execute ()
  • 1 public slot inherited from QObject

Signals

void canceled ()
void error ( int error, const QString & errorString )
void errorChanged ()
void finished ()
void galleryChanged ()
void progressChanged ( int current, int maximum )
void stateChanged ( QGalleryAbstractRequest::State state )
void supportedChanged ()

Protected Functions

virtual void setResponse ( QGalleryAbstractResponse * response ) = 0
  • 7 protected functions inherited from QObject

Additional Inherited Members

  • 1 public variable inherited from QObject
  • 4 static public members inherited from QObject
  • 2 protected variables inherited from QObject

Detailed Description

The QGalleryAbstractRequest class provides a base class for gallery requests.

Gallery requests are the interface through which clients can interact with a gallery to execute queries or perform actions. QAbstractGalleryRequest manages executing requests against a gallery and reporting the state of responses.

In order to execute a request it is first necessary to assign the gallery to the request. If the request is supported by the gallery the supported property will be true, otherwise if the request is not supported or no gallery is assigned to the request supported will be false.

Once a request has been assigned a gallery and its own arguments it can be executed. As requests are asynchronous results will not be available immediately, instead the request will go into an Active state until it is finished. If the request is successful the finished() signal will be emitted and if not the error() signal will be emitted, in both cases the stateChanged() signal will be emitted with the new state of the request.

Active requests can be canceled by calling the cancel() function. Canceling a request can also be an asynchronous action and does not always prevent a request from finishing successfully such as when the earliest possible point to interrupt a request is on completion. If a canceled request isn't aborted immediately it will go into the Canceling state until it is aborted and enters the Canceled state or succeeds and enters the Finished state.

Some requests support automatically updating their results in response to changes in their source data or some other event. A request that will provide these sort of updates will enter the Idle state upon finishing its initial request. From the Idle state a request may return to the Active state itself to refresh its results or update it results immeditately if a a new query is not required. Cancelling an idle request will put it into the Finished state and prevent future updates.

While requests are asynchronous it is possible to use them in a synchronous manner by using the waitForFinished() function to block until the request has finished.

Member Type Documentation

enum QGalleryAbstractRequest::RequestError

Constant Value Description
QGalleryAbstractRequest::NoError 0 No error.
QGalleryAbstractRequest::NoGallery 1 No gallery found.
QGalleryAbstractRequest::NotSupported 2 Request is not supported.
QGalleryAbstractRequest::GalleryError 100 The gallery is wrong or corrupt.

enum QGalleryAbstractRequest::RequestType

Identifies the type of a request.

Constant Value Description
QGalleryAbstractRequest::QueryRequest 0 The request is a QGalleryQueryRequest.
QGalleryAbstractRequest::ItemRequest 1 The request is a QGalleryItemRequest.
QGalleryAbstractRequest::TypeRequest 2 The request is a QGalleryTypeRequest

enum QGalleryAbstractRequest::State

Identifies the state of a gallery request.

Constant Value Description
QGalleryAbstractRequest::Inactive 0 The request has not been executed.
QGalleryAbstractRequest::Active 1 The request is currently executing.
QGalleryAbstractRequest::Canceling 2 The request was canceled, but hasn't yet reached the Canceled state.
QGalleryAbstractRequest::Canceled 3 The request was canceled.
QGalleryAbstractRequest::Idle 4 The request has finished, but may return to the active state in response to an internal event.
QGalleryAbstractRequest::Finished 5 The request is finished.
QGalleryAbstractRequest::Error 6 The request runs into an error.

Property Documentation

currentProgress : const int

This property holds the current progress of a request.

This property was introduced in Qt Mobility 1.1.

Access functions:

int currentProgress () const

Notifier signal:

void progressChanged ( int current, int maximum )

error : const int

This property holds the error encountered by an unsuccessful request.

Common errors are defined in Error, more specific errors are defined by the gallery implementations such as in QDocumentGallery::Error.

This property was introduced in Qt Mobility 1.1.

Access functions:

int error () const
void error ( int error, const QString & errorString )

Notifier signal:

void errorChanged ()

errorString : const QString

This property holds a string describing the cause of an error in more detail.

This may be an empty string if more information is not known.

This property was introduced in Qt Mobility 1.1.

Access functions:

QString errorString () const

Notifier signal:

void errorChanged ()

gallery : QAbstractGallery *

This property holds the gallery service a request acts on.

This property was introduced in Qt Mobility 1.1.

Access functions:

QAbstractGallery * gallery () const
void setGallery ( QAbstractGallery * gallery )

Notifier signal:

void galleryChanged ()

maximumProgress : const int

This property holds the maximum value of currentProgress.

This property was introduced in Qt Mobility 1.1.

Access functions:

int maximumProgress () const

Notifier signal:

void progressChanged ( int current, int maximum )

state : const State

This property holds the state of a request.

This property was introduced in Qt Mobility 1.1.

Access functions:

State state () const

Notifier signal:

void stateChanged ( QGalleryAbstractRequest::State state )

supported : const bool

This property holds whether a request is supported by its current gallery.

This property was introduced in Qt Mobility 1.1.

Access functions:

bool isSupported () const

Notifier signal:

void supportedChanged ()

Member Function Documentation

QGalleryAbstractRequest::QGalleryAbstractRequest ( RequestType type, QObject * parent = 0 )

Constructs a new gallery type request.

The parent is passed to QObject.

This function was introduced in Qt Mobility 1.1.

QGalleryAbstractRequest::QGalleryAbstractRequest ( QAbstractGallery * gallery, RequestType type, QObject * parent = 0 )

Constructs a new type request for the given gallery.

The parent is passed to QObject.

This function was introduced in Qt Mobility 1.1.

QGalleryAbstractRequest::~QGalleryAbstractRequest ()

Destroys a gallery request.

void QGalleryAbstractRequest::cancel () [slot]

Cancels the execution of a request. If the request is idle this will stop any future updates.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::canceled () [signal]

Signals that a request was canceled before it could finish.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::clear () [slot]

Clears the results of a request.

If the request is active or idle it will be canceled.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::errorChanged () [signal]

Signals that the error and errorString properties have changed.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::execute () [slot]

Executes a request.

Note: A valid gallery must be set before a request can be executed.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::finished () [signal]

Signals that a request has finished.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::galleryChanged () [signal]

Signals that the value of gallery has changed.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::progressChanged ( int current, int maximum ) [signal]

Signals that the current or maximum progress value has changed.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::setResponse ( QGalleryAbstractResponse * response ) [pure virtual protected]

Sets the response to an executed request.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::stateChanged ( QGalleryAbstractRequest::State state ) [signal]

Signals that the state of a request has changed.

This function was introduced in Qt Mobility 1.1.

void QGalleryAbstractRequest::supportedChanged () [signal]

Signals the supported property has changed.

This function was introduced in Qt Mobility 1.1.

RequestType QGalleryAbstractRequest::type () const

Returns the type of a request.

This function was introduced in Qt Mobility 1.1.

bool QGalleryAbstractRequest::waitForFinished ( int msecs )

Waits for msecs for the a request to finish.

Returns true if the request has finished on return, and returns false if the wait time expires or the request is inactive or idle.

This function was introduced in Qt Mobility 1.1.

© 2008-2011 Nokia Corporation and/or its subsidiaries. Nokia, Qt and their respective logos are trademarks of Nokia Corporation in Finland and/or other countries worldwide.

All other trademarks are property of their respective owners. Privacy Policy


Licensees holding valid Qt Commercial licenses may use this document in accordance with the Qt Commercial License Agreement provided with the Software or, alternatively, in accordance with the terms contained in a written agreement between you and Nokia.

Alternatively, this document may be used under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation.