- Qt 6.9
- Qt Location
- C++ Classes
- QGeoCodingManagerEngine
- Qt 6.9.3 Reference Documentation

# QGeoCodingManagerEngine Class

The QGeoCodingManagerEngine class provides an interface and convenience methods to implementers of QGeoServiceProvider plugins who want to provide support for geocoding operations. More...

Header: | `#include <QGeoCodingManagerEngine>`
qmake: | `QT += location`
Inherits: | QObject

- List of all members, including inherited members

## Public Functions

| QGeoCodingManagerEngine(const QVariantMap &parameters, QObject *parent = nullptr)
virtual | ~QGeoCodingManagerEngine()
virtual QGeoCodeReply * | geocode(const QGeoAddress &address, const QGeoShape &bounds)
virtual QGeoCodeReply * | geocode(const QString &address, int limit, int offset, const QGeoShape &bounds)
QLocale | locale() const
QString | managerName() const
int | managerVersion() const
virtual QGeoCodeReply * | reverseGeocode(const QGeoCoordinate &coordinate, const QGeoShape &bounds)
void | setLocale(const QLocale &locale)

## Signals

void | errorOccurred(QGeoCodeReply *reply, QGeoCodeReply::Error error, const QString &errorString = QString())
void | finished(QGeoCodeReply *reply)

## Detailed Description

Note: There are no source or binary compatibility guarantees for the backend classes. The API is only guaranteed to work with the Qt version it was developed against. API changes will however only be made in minor releases. (6.6, 6.7, and so on.)

In the default implementation, supportsGeocoding() and supportsReverseGeocoding() returns false while geocode() and reverseGeocode() cause QGeoCodeReply::UnsupportedOptionError to occur.

If the service provider supports geocoding the subclass should provide an implementation of geocode() and call setSupportsGeocoding(true) at some point in time before geocode() is called.

Similarly, if the service provider supports reverse geocoding the subclass should provide an implementation reverseGeocode() and call setSupportsReverseGeocoding(true) at some point in time before reverseGeocode() is called.

A subclass of QGeoCodingManagerEngine will often make use of a subclass fo QGeoCodeReply internally, in order to add any engine-specific data (such as a QNetworkReply object for network-based services) to the QGeoCodeReply instances used by the engine.

See also QGeoCodingManager.

## Member Function Documentation

### `[explicit]` QGeoCodingManagerEngine::QGeoCodingManagerEngine(const QVariantMap &parameters, QObject *parent = nullptr)

Constructs a new engine with the specified parent, using parameters to pass any implementation specific data to the engine.

### `[virtual noexcept]` QGeoCodingManagerEngine::~QGeoCodingManagerEngine()

Destroys this engine.

### `[signal]` void QGeoCodingManagerEngine::errorOccurred(QGeoCodeReply *reply, QGeoCodeReply::Error error, const QString &errorString = QString())

This signal is emitted when an error has been detected in the processing of reply. The QGeoCodingManagerEngine::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 QGeoCodeReply::errorOccurred() will be emitted at the same time.

Note: Do not delete the reply object in the slot connected to this signal. Use deleteLater() instead.

### `[signal]` void QGeoCodingManagerEngine::finished(QGeoCodeReply *reply)

This signal is emitted when reply has finished processing.

If reply::error() equals QGeoCodeReply::NoError then the processing finished successfully.

This signal and QGeoCodeReply::finished() will be emitted at the same time.

Note: Do not delete the reply object in the slot connected to this signal. Use deleteLater() instead.

### `[virtual]` QGeoCodeReply *QGeoCodingManagerEngine::geocode(const QGeoAddress &address, const QGeoShape &bounds)

Begins the geocoding of address. Geocoding is the process of finding a coordinate that corresponds to a given address.

A QGeoCodeReply object will be returned, which can be used to manage the geocoding operation and to return the results of the operation.

This engine and the returned QGeoCodeReply object will emit signals indicating if the operation completes or if errors occur.

If supportsGeocoding() returns false an QGeoCodeReply::UnsupportedOptionError will occur.

Once the operation has completed, QGeoCodeReply::locations() can be used to retrieve the results, which will consist of a list of QGeoLocation objects. These objects 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 a valid QGeoShape it will be used to limit the results to those that are contained by 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 QGeoCodingManagerEngine::finished(), QGeoCodingManagerEngine::errorOccurred(), QGeoCodeReply::finished() or QGeoCodeReply::errorOccurred() with deleteLater().

### `[virtual]` QGeoCodeReply *QGeoCodingManagerEngine::geocode(const QString &address, int limit, int offset, const QGeoShape &bounds)

Begins geocoding for a location matching address.

A QGeoCodeReply object will be returned, which can be used to manage the geocoding operation and to return the results of the operation.

This engine and the returned QGeoCodeReply object will emit signals indicating if the operation completes or if errors occur.

Once the operation has completed, QGeoCodeReply::locations() can be used to retrieve the results, which will consist of a list of QGeoLocation objects. These objects represent a combination of coordinate and address data.

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 geocoding service to not return the first offset results.

The limit and offset results are used together to implement paging.

If bounds is non-null and a valid QGeoShape it will be used to limit the results to those that are contained by bounds.

The user is responsible for deleting the returned reply object, although this can be done in the slot connected to QGeoCodingManagerEngine::finished(), QGeoCodingManagerEngine::errorOccurred(), QGeoCodeReply::finished() or QGeoCodeReply::errorOccurred() with deleteLater().

### QLocale QGeoCodingManagerEngine::locale() const

Returns the locale used to hint to this geocoding manager about what language to use for the results.

See also setLocale().

### QString QGeoCodingManagerEngine::managerName() const

Returns the name which this engine implementation uses to distinguish itself from the implementations provided by other plugins.

The combination of managerName() and managerVersion() should be unique amongst plugin implementations.

### int QGeoCodingManagerEngine::managerVersion() const

Returns the version of this engine implementation.

The combination of managerName() and managerVersion() should be unique amongst plugin implementations.

### `[virtual]` QGeoCodeReply *QGeoCodingManagerEngine::reverseGeocode(const QGeoCoordinate &coordinate, const QGeoShape &bounds)

Begins the reverse geocoding of coordinate. Reverse geocoding is the process of finding an address that corresponds to a given coordinate.

A QGeoCodeReply object will be returned, which can be used to manage the reverse geocoding operation and to return the results of the operation.

This engine and the returned QGeoCodeReply object will emit signals indicating if the operation completes or if errors occur.

If supportsReverseGeocoding() returns false an QGeoCodeReply::UnsupportedOptionError will occur.

At that point QGeoCodeReply::locations() can be used to retrieve the results, which will consist of a list of QGeoLocation objects. These objects 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 QGeoShape it will be used to limit the results to those that are contained by bounds.

The user is responsible for deleting the returned reply object, although this can be done in the slot connected to QGeoCodingManagerEngine::finished(), QGeoCodingManagerEngine::errorOccurred(), QGeoCodeReply::finished() or QGeoCodeReply::errorOccurred() with deleteLater().

### void QGeoCodingManagerEngine::setLocale(const QLocale &locale)

Sets the locale to be used by this manager to locale.

If this geocoding 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().