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QGeoSearchManager Class ReferenceThe QGeoSearchManager class provides support for searching operations related to geographic information. More... #include <QGeoSearchManager> Inherits QObject. Public Types
Public Functions
Signals
Additional Inherited Members
Detailed DescriptionThe QGeoSearchManager class provides support for searching operations related to geographic information. The geocode(), reverseGeocode() and search() functions return QGeoSearchReply objects, which manage these operations and report on the result of the operations and any errors which may have occurred. The geocode() and reverseGeocode() functions can be used to convert QGeoAddress instances to QGeoCoordinate instances and vice-versa. The search() function allows a user to perform a free text search for place information. If the string provided can be interpreted as an address it can be geocoded to coordinate information, and the string can also be used to search a landmarks database, depending on the level of support supplied by the service provider. The defaultLandmarkManager() function will return a QLandmarkManager instance if access to the service providers landmark database is available outside of the search() method. A user can supply other QLandmarkManager instances to be searched during the execution of search() with setAdditionalLandmarkManagers(). This means that a personal database store can be combined with a public source of database information with very little effort. Note: At present the additional landmark managers only search for the search string in the name of the landmarks. Instances of QGeoSearchManager can be accessed with QGeoServiceProvider::searchManager(). A small example of the usage of QGeoSearchManager and the handling of QLandmark results follows: class MySearchHandler : public QObject
{
Q_OBJECT
public:
MySearchHandler(QGeoSearchManager *searchManager, QString searchString)
{
QGeoSearchReply *reply = searchManager->search(searchString);
if (reply->isFinished()) {
if (reply->error() == QGeoSearchReply::NoError) {
searchResults(reply);
else
searchError(reply, reply->error(), reply->errorString());
return;
}
connect(searchManager,
SIGNAL(finished(QGeoSearchReply*)),
this,
SLOT(searchResults(QGeoSearchReply*)));
connect(searchManager,
SIGNAL(error(QGeoSearchReply*,QGeoSearchReply::Error,QString)),
this
SLOT(searchError(QGeoSearchReply*,QGeoSearchReply::Error,QString)));
}
private slots:
void searchResults(QGeoSearchReply *reply)
{
// The QLandmark results can be created from the simpler
// QGeoPlace results if that is required.
QList<QLandmark> landmarks;
for (int i = 0; i < reply->places().size(); ++i) {
if (reply->places().at(i).isLandmark())
landmarks.append(QLandmark(reply->places().at(i)));
}
// ... now we have to make use of the places and landmarks ...
reply->deleteLater();
}
void searchError(QGeoSearchReply *reply, QGeoSearchReply::Error error, const QString &errorString)
{
// ... inform the user that an error has occurred ...
reply->deleteLater();
}
};
Member Type Documentation
flags QGeoSearchManager::SearchTypes |
| Constant | Value | Description |
|---|---|---|
| QGeoSearchManager::SearchNone | 0x0000 | Do not use the search string. |
| QGeoSearchManager::SearchGeocode | 0x0001 | Use the search string as a textual address in a geocoding operation. |
| QGeoSearchManager::SearchLandmarks | 0x0002 | Use the search string for free-text search against the available landmark information sources. |
| QGeoSearchManager::SearchAll | 0xFFFF | All available information sources should be used as part of the search. |
The SearchTypes type is a typedef for QFlags<SearchType>. It stores an OR combination of SearchType values.
Member Function Documentation
QGeoSearchManager::~QGeoSearchManager ()
Destroys this manager.
void QGeoSearchManager::addAdditionalLandmarkManager ( QLandmarkManager * landmarkManager )
Adds landmarkManager to the list of landmark managers that will be used with search().
These landmark managers will be used along with the landmark manager returned by defaultLandmarkManager().
QList<QLandmarkManager *> QGeoSearchManager::additionalLandmarkManagers () const
Returns the landmark managers that will be used with search().
These landmark managers will be used along with the landmark manager returned by defaultLandmarkManager().
See also setAdditionalLandmarkManagers().
QLandmarkManager * QGeoSearchManager::defaultLandmarkManager () const
Returns the landmark manager provided by the service provider for use with search().
Will return 0 if the no landmark manager is associated with the service provider. This does not indicate that search() does not support landmark searching, only that any landmark searching which occurs within in search() is done without the use of a QLandmarkManager.
void QGeoSearchManager::error ( QGeoSearchReply * reply, QGeoSearchReply::Error error, QString errorString = QString() ) [signal]
This signal is emitted when an error has been detected in the processing of reply. The QGeoSearchManager::finished() signal will probably follow.
The error will be described by the error code error. If errorString is not empty it will contain a textual description of the error.
This signal and QGeoSearchReply::error() will be emitted at the same time.
Note: Do no delete the reply object in the slot connected to this signal. Use deleteLater() instead.
void QGeoSearchManager::finished ( QGeoSearchReply * reply ) [signal]
This signal is emitted when reply has finished processing.
If reply::error() equals QGeoSearchReply::NoError then the processing finished successfully.
This signal and QGeoSearchReply::finished() will be emitted at the same time.
Note: Do no delete the reply object in the slot connected to this signal. Use deleteLater() instead.
QGeoSearchReply * QGeoSearchManager::geocode ( const QGeoAddress & address, QGeoBoundingArea * bounds = 0 )
Begins the geocoding of address. Geocoding is the process of finding a coordinate that corresponds to a given address.
A QGeoSearchReply object will be returned, which can be used to manage the geocoding operation and to return the results of the operation.
This manager and the returned QGeoSearchReply object will emit signals indicating if the operation completes or if errors occur.
If supportsGeocoding() returns false an QGeoSearchReply::UnsupportedOptionError will occur.
Once the operation has completed, QGeoSearchReply::places() can be used to retrieve the results, which will consist of a list of QGeoPlace objects. These object represent a combination of coordinate and address data.
The address data returned in the results may be different from address. This will usually occur if the geocoding service backend uses a different canonical form of addresses or if address was only partially filled out.
If bounds is non-null and valid QGeoBoundingArea it will be used to limit the results to thos that are contained within bounds. This is particularly useful if address is only partially filled out, as the service will attempt to geocode all matches for the specified data.
The user is responsible for deleting the returned reply object, although this can be done in the slot connected to QGeoSearchManager::finished(), QGeoSearchManager::error(), QGeoSearchReply::finished() or QGeoSearchReply::error() with deleteLater().
QLocale QGeoSearchManager::locale () const
Returns the locale used to hint to this search manager about what language to use for the results.
See also setLocale().
QString QGeoSearchManager::managerName () const
Returns the name of the engine which implements the behaviour of this search manager.
The combination of managerName() and managerVersion() should be unique amongst the plugin implementations.
int QGeoSearchManager::managerVersion () const
Returns the version of the engine which implements the behaviour of this search manager.
The combination of managerName() and managerVersion() should be unique amongst the plugin implementations.
QGeoSearchReply * QGeoSearchManager::reverseGeocode ( const QGeoCoordinate & coordinate, QGeoBoundingArea * bounds = 0 )
Begins the reverse geocoding of coordinate. Reverse geocoding is the process of finding an address that corresponds to a given coordinate.
A QGeoSearchReply object will be returned, which can be used to manage the reverse geocoding operation and to return the results of the operation.
This manager and the returned QGeoSearchReply object will emit signals indicating if the operation completes or if errors occur.
If supportsReverseGeocoding() returns false an QGeoSearchReply::UnsupportedOptionError will occur.
At that point QGeoSearchReply::places() can be used to retrieve the results, which will consist of a list of QGeoPlace objects. These object represent a combination of coordinate and address data.
The coordinate data returned in the results may be different from coordinate. This will usually occur if the reverse geocoding service backend shifts the coordinates to be closer to the matching addresses, or if the backend returns results at multiple levels of detail.
If multiple results are returned by the reverse geocoding service backend they will be provided in order of specificity. This normally occurs if the backend is configured to reverse geocode across multiple levels of detail. As an example, some services will return address and coordinate pairs for the street address, the city, the state and the country.
If bounds is non-null and a valid QGeoBoundingBox it will be used to limit the results to thos that are contained within bounds.
The user is responsible for deleting the returned reply object, although this can be done in the slot connected to QGeoSearchManager::finished(), QGeoSearchManager::error(), QGeoSearchReply::finished() or QGeoSearchReply::error() with deleteLater().
QGeoSearchReply * QGeoSearchManager::search ( const QString & searchString, SearchTypes searchTypes = SearchTypes( SearchAll ), int limit = -1, int offset = 0, QGeoBoundingArea * bounds = 0 )
Begins searching for a place matching searchString. The value of searchTypes will determine whether the search is for addresses only, for landmarks only or for both.
A QGeoSearchReply object will be returned, which can be used to manage the geocoding operation and to return the results of the operation.
This manager and the returned QGeoSearchReply object will emit signals indicating if the operation completes or if errors occur.
If supportsGeocoding() returns false and searchTypes is QGeoSearchManager::SearchGeocode an QGeoSearchReply::UnsupportedOptionError will occur.
Once the operation has completed, QGeoSearchReply::places() can be used to retrieve the results, which will consist of a list of QGeoPlace objects. These object represent a combination of coordinate and address data.
If any of the QGeoPlace instances in the results have landmark associated data, QGeoPlace::isLandmark() will return true and QLandmark::QLandmark(const QGeoPlace &place) can be used to convert the QGeoPlace instance into a QLandmark instance.
If searchTypes is QGeoSearchManager::SearchLandmarks or QGeoSearchManager::SearchAll, a free text landmark search will be performed. The results will be a combination of the backend specific landmark search and the same free text search applied to each of the QLandmarkManager instances in additionalLandmarkManagers().
Note: At present the additional landmark managers only search for the search string in the name of the landmarks.
If limit is -1 the entire result set will be returned, otherwise at most limit results will be returned.
The offset parameter is used to ask the search service to not return the first offset results.
The limit and offset results are used together to implement paging.
If additional landmark managers have been setup the number of results returned will be at most (1 + number of additional landmark managers) * limit. This happens because the results are requested from all sources, combined, and returned once all sources have responded.
If bounds is non-null and a valid QGeoBoundingArea it will be used to limit the results to thos that are contained within bounds.
The user is responsible for deleting the returned reply object, although this can be done in the slot connected to QGeoSearchManager::finished(), QGeoSearchManager::error(), QGeoSearchReply::finished() or QGeoSearchReply::error() with deleteLater().
void QGeoSearchManager::setAdditionalLandmarkManagers ( const QList<QLandmarkManager *> & landmarkManagers )
Sets the landmark managers to be used with search() to landmarkManagers.
These landmark managers will be used along with the landmark manager returned by defaultLandmarkManager().
See also additionalLandmarkManagers().
void QGeoSearchManager::setLocale ( const QLocale & locale )
Sets the locale to be used by the this manager to locale.
If this search manager supports returning the results in different languages, they will be returned in the language of locale.
The locale used defaults to the system locale if this is not set.
See also locale().
SearchTypes QGeoSearchManager::supportedSearchTypes () const
Returns the search types supported by the search() function with this manager.
bool QGeoSearchManager::supportsGeocoding () const
Returns whether this manager supports geocoding.
bool QGeoSearchManager::supportsReverseGeocoding () const
Returns whether this manager supports reverse geocoding.