QgsLocator class

Handles the management of QgsLocatorFilter objects and async collection of search results from them.

Reference

QgsLocator acts as both a registry for QgsLocatorFilter objects and a means of firing up asynchronous queries against these filter objects.

Filters are first registered to the locator by calling registerFilter(). Registering filters transfers their ownership to the locator object. Plugins which register filters to the locator must take care to correctly call deregisterFilter() and deregister their filter upon plugin unload to avoid crashes.

In order to trigger a search across registered filters, the fetchResults() method is called. This triggers threaded calls to QgsLocatorFilter::fetchResults() for all registered filters. As individual filters find matching results, the foundResult() signal will be triggered for each result. Callers should connect this signal to an appropriate slot designed to collect and handle these results. Since foundResult() is triggered whenever a filter encounters an individual result, it will usually be triggered many times for a single call to fetchResults().

Public static variables

static const QList<QString> CORE_FILTERS: List of core filters (i.e. not plugin filters)

Constructors, destructors, conversion operators

QgsLocator(QObject* parent = nullptr): Constructor for QgsLocator.
~QgsLocator() override: Destructor for QgsLocator.

Public functions

void cancel(): Cancels any current running query, and blocks until query is completely canceled by all filters.
void cancelWithoutBlocking(): Triggers cancelation of any current running query without blocking.
void clearPreviousResults(): Will call clearPreviousResults on all filters.
void deregisterFilter(QgsLocatorFilter* filter): Deregisters a filter from the locator and deletes it.
void fetchResults(const QString& string, const QgsLocatorContext& context, QgsFeedback* feedback = nullptr): Triggers the background fetching of filter results for a specified search string.
auto filters(const QString& prefix = QString()) -> QList<QgsLocatorFilter*>: Returns the list of filters registered in the locator.
auto isRunning() const -> bool: Returns true if a query is currently being executed by the locator.
auto prefixedFilters() const -> Q_DECL_DEPRECATED QMap<QString, QgsLocatorFilter*> deprecated: Returns a map of prefix to filter, for all registered filters with valid prefixes.
void registerFilter(QgsLocatorFilter* filter): Registers a filter within the locator.

Signals

void finished(): Emitted when locator has finished a query, either as a result of successful completion or early cancelation.
void foundResult(const QgsLocatorResult& result): Emitted whenever a filter encounters a matching result after the fetchResults() method is called.

Function documentation

QgsLocator::~QgsLocator() override

Destructor for QgsLocator.

Destruction will block while any currently running query is terminated.

void QgsLocator::cancel()

Cancels any current running query, and blocks until query is completely canceled by all filters.

void QgsLocator::cancelWithoutBlocking()

Triggers cancelation of any current running query without blocking.

The query may take some time to cancel after calling this.

void QgsLocator::clearPreviousResults()

Will call clearPreviousResults on all filters.

void QgsLocator::deregisterFilter(QgsLocatorFilter* filter)

Deregisters a filter from the locator and deletes it.

Calling this will block whilst any currently running query is terminated.

Plugins which register filters to the locator must take care to correctly call deregisterFilter() to deregister their filters upon plugin unload to avoid crashes.

void QgsLocator::fetchResults(const QString& string, const QgsLocatorContext& context, QgsFeedback* feedback = nullptr)

Triggers the background fetching of filter results for a specified search string.

The context argument encapsulates the context relating to the search (such as a map extent to prioritize).

If specified, the feedback object must exist for the lifetime of this query.

The foundResult() signal will be emitted for each individual result encountered by the registered filters.

QList<QgsLocatorFilter*> QgsLocator::filters(const QString& prefix = QString())

Returns the list of filters registered in the locator.

Parameters
prefix	If prefix is not empty, the list returned corresponds to the filter with the given active prefix

Q_DECL_DEPRECATED QMap<QString, QgsLocatorFilter*> QgsLocator::prefixedFilters() const

Returns a map of prefix to filter, for all registered filters with valid prefixes.

void QgsLocator::registerFilter(QgsLocatorFilter* filter)

Registers a filter within the locator.

Ownership of the filter is transferred to the locator.