              
QGalleryQueryRequest Class ReferenceThe QGalleryQueryRequest class provides a request for a set of items from a gallery. More... #include <QGalleryQueryRequest> Inherits QGalleryAbstractRequest. Public Types
Properties
Public Functions
Signals
Reimplemented Protected Functions
Additional Inherited Members
Detailed DescriptionThe QGalleryQueryRequest class provides a request for a set of items from a gallery. QGalleryItemRequest executes a query which returns information about a set gallery item of gallery items matching some query criteria. For each item matching the query criteria the request will return an itemUrl, an itemType, resources and meta-data values for the properties listed in propertyNames. The rootType property identifies the type of gallery item the request should return, if the root type has derivative types (i.e. an audio file is just a special case of a regular file) these will also be included in the result set. The rootItem property takes the ID of an item the query should only return the children of. Depending on the scope of the query this may be {AllDescendents}{all descendents} or just the {DirectDescendents} {direct descendents} of the root item. The results of a query can be further limited by setting a filter on the request. The request will evaluate the QGalleryFilter and only include items with meta-data matching the expression. The order the results are returned in can be specified in the sortPropertyNames property which takes an ordered list of property names. By default properties are sorted in ascending order, but this can be specified explicitly be prefixing the property name with a '+' character for ascending order and a '-' character for descending order. If the autoUpdate property is true when the request is executed it will enter an Idle state on finishing and will refresh the queried information if the items matching the query change. If the gallery can't provide updates it will instead go immediately to the Finished state. Automatic updates can be canceled by calling cancel() on a idle request. Only one item in a query can be accessed at a time, so before information about an item can be accessed it must be selected using one of the fetch() functions. When a new index is selected the result set will emit the currentIndexChanged() signal, and when the currently selected item changes the currentItemChanged() signal will be emitted. If the currentIndex() contains a gallery item isValid() will return true, otherwise it will return false. Information identifying the current item in the request can be accessed using the itemId(), itemUrl() and itemType() functions. For each meta-data property returned by a query a unique key will be provided, this cab be queried by passing the property's name to the propertyKey() function. Passing this key to the metaData() function will return the current item's value for that property. Some queries may return items with editable meta-data values which can be changed using the setMetaData() function. The attributes of a meta-data property such as whether it's writable can be queried from propertyAttributes() and the type of value that will returned by metaData() can be queried using propertyType(). See also QDocumentGallery and QGalleryQueryModel. Member Type Documentation
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| Constant | Value | Description |
|---|---|---|
| QGalleryQueryRequest::AllDescendants | 0 | The query will return all descendents of the scope item. |
| QGalleryQueryRequest::DirectDescendants | 1 | The query will return only direct descendents of the scope item. |
Property Documentation
autoUpdate : bool
This property holds whether a the results of a request should be updated after a request has finished.
If this is true the request will go into the Idle state when the request has finished rather than returning to Inactive.
Access functions:
| bool | autoUpdate () const |
| void | setAutoUpdate ( bool enabled ) |
Notifier signal:
| void | autoUpdateChanged () |
currentIndex : int
This property holds the index of current item.
Access functions:
| int | currentIndex () const |
| bool | seek ( int index, bool relative = false ) |
Notifier signal:
| void | currentItemChanged () |
filter : QGalleryFilter
This property holds a filter identifying the items a request should return.
If no filter is set the results of the request will be determined by the rootType and rootItem properties.
Access functions:
| QGalleryFilter | filter () const |
| void | setFilter ( const QGalleryFilter & filter ) |
Notifier signal:
| void | filterChanged () |
itemId : const QVariant
This property holds the ID of the current item.
Access functions:
| QVariant | itemId () const |
Notifier signal:
| void | currentItemChanged () |
itemType : const QString
This property holds he type of the current item.
Access functions:
| QString | itemType () const |
Notifier signal:
| void | currentItemChanged () |
itemUrl : const QUrl
This property holds the URL of the current item.
Access functions:
| QUrl | itemUrl () const |
Notifier signal:
| void | currentItemChanged () |
limit : int
This property holds the maximum number of items a query should return.
Access functions:
| int | limit () const |
| void | setLimit ( int limit ) |
Notifier signal:
| void | limitChanged () |
offset : int
This property holds the offset of the first item a query should return.
Access functions:
| int | offset () const |
| void | setOffset ( int offset ) |
Notifier signal:
| void | offsetChanged () |
propertyNames : QStringList
This property holds a list of names of meta-data properties a request should return values for.
Access functions:
| QStringList | propertyNames () const |
| void | setPropertyNames ( const QStringList & names ) |
Notifier signal:
| void | propertyNamesChanged () |
resources : const QList<QGalleryResource>
This property holds the resources of the current item.
Access functions:
| QList<QGalleryResource> | resources () const |
Notifier signal:
| void | currentItemChanged () |
rootItem : QVariant
This property holds the ID of an item the query should return the descendents of.
Access functions:
| QVariant | rootItem () const |
| void | setRootItem ( const QVariant & itemId ) |
Notifier signal:
| void | rootItemChanged () |
rootType : QString
This property holds the root item type the results of a query should be restricted to.
Access functions:
| QString | rootType () const |
| void | setRootType ( const QString & itemType ) |
Notifier signal:
| void | rootTypeChanged () |
scope : QGalleryQueryRequest::Scope
This property holds whether all descendants of the rootItem should be returned by a request or just the direct descendants.
Access functions:
| QGalleryQueryRequest::Scope | scope () const |
| void | setScope ( QGalleryQueryRequest::Scope scope ) |
Notifier signal:
| void | scopeChanged () |
sortPropertyNames : QStringList
This property holds a list of names of meta-data properties a request should sort its results on.
Prefixing a property name with the '+' character indicates it should be sorted in ascending order, and a '-' character prefix indicates a descending order. If there is no prefix ascending order is assumed.
Access functions:
| QStringList | sortPropertyNames () const |
| void | setSortPropertyNames ( const QStringList & names ) |
Notifier signal:
| void | sortPropertyNamesChanged () |
valid : const bool
This property holds whether the result set is currently positioned on a valid item.
Access functions:
| bool | isValid () const |
Notifier signal:
| void | currentItemChanged () |
Member Function Documentation
QGalleryQueryRequest::QGalleryQueryRequest ( QObject * parent = 0 )
Constructs a new gallery query request.
The parent is passed to QObject.
QGalleryQueryRequest::QGalleryQueryRequest ( QAbstractGallery * gallery, QObject * parent = 0 )
Contructs a new query request for the given gallery.
The parent is passed to QObject.
QGalleryQueryRequest::~QGalleryQueryRequest ()
Destroys a gallery query request.
void QGalleryQueryRequest::autoUpdateChanged () [signal]
Signals that the value of autoUpdate has changed.
void QGalleryQueryRequest::currentItemChanged () [signal]
Signals that the item the result set is positioned on has changed.
void QGalleryQueryRequest::filterChanged () [signal]
Signals that the value of filter has changed.
bool QGalleryQueryRequest::first ()
Seeks to the first item in the result set.
Returns true if the position of the result set is valid after the seek; and false otherwise.
int QGalleryQueryRequest::itemCount () const
Returns the number of items returned by a query.
bool QGalleryQueryRequest::last ()
Seeks to the last item in the result set.
Returns true if the position of the result set is valid after the seek; and false otherwise.
void QGalleryQueryRequest::limitChanged () [signal]
Signals that the value of limit has changed.
QVariant QGalleryQueryRequest::metaData ( int key ) const
Returns the value of a meta-data property identified by key for the current item.
See also setMetaData().
QVariant QGalleryQueryRequest::metaData ( const QString & property ) const
Returns the value of a meta-data property for the current item.
bool QGalleryQueryRequest::next ()
Seeks to the next item in the result set.
Returns true if the position of the result set is valid after the seek; and false otherwise.
void QGalleryQueryRequest::offsetChanged () [signal]
Signals that the value of offset has changed.
bool QGalleryQueryRequest::previous ()
Seeks to the previous item in the result set.
Returns true if the position of the result set is valid after the seek; and false otherwise.
QGalleryProperty::Attributes QGalleryQueryRequest::propertyAttributes ( int key ) const
Returns the attributes of the property identified by key.
int QGalleryQueryRequest::propertyKey ( const QString & property ) const
Returns the key of property.
void QGalleryQueryRequest::propertyNamesChanged () [signal]
Signals that the value of propertyNames has changed.
QVariant::Type QGalleryQueryRequest::propertyType ( int key ) const
Returns the type of the property identified by key.
QGalleryResultSet * QGalleryQueryRequest::resultSet () const
Returns the result set containing the results of a query.
void QGalleryQueryRequest::resultSetChanged ( QGalleryResultSet * resultSet ) [signal]
Signals that the resultSet containing the results of a query have changed.
void QGalleryQueryRequest::rootItemChanged () [signal]
Signals that the value of rootItem has changed.
void QGalleryQueryRequest::rootTypeChanged () [signal]
Signals that the value of rootType has changed.
void QGalleryQueryRequest::scopeChanged () [signal]
Signals that the value of scope has changed.
bool QGalleryQueryRequest::setMetaData ( int key, const QVariant & value )
Sets the value of a meta-data property identified by key for the current item.
Returns true if the value was changed; otherwise returns false.
See also metaData().
bool QGalleryQueryRequest::setMetaData ( const QString & property, const QVariant & value )
Sets the
| Constant | Value | Description |
|---|---|---|
| QGalleryQueryRequest::of | ? | a meta-data property for the current item. |
Returns true if the value was changed; otherwise returns false.
void QGalleryQueryRequest::setResponse ( QGalleryAbstractResponse * response ) [virtual protected]
Reimplemented from QGalleryAbstractRequest::setResponse().
void QGalleryQueryRequest::sortPropertyNamesChanged () [signal]
Signals that the value of sortPropertyNames has changed.