- Qt 5.15
- Qt Help
- C++ Classes
- QHelpSearchEngine
- Qt 5.15.19 Reference Documentation

# QHelpSearchEngine Class

The QHelpSearchEngine class provides access to widgets reusable to integrate fulltext search as well as to index and search documentation. More...

Header: | #include <QHelpSearchEngine>
qmake: | QT += help
Since: | Qt 4.4
Inherits: | QObject

This class was introduced in Qt 4.4.

- List of all members, including inherited members
- Obsolete members

## Public Functions

| QHelpSearchEngine(QHelpEngineCore *helpEngine, QObject *parent = nullptr)
virtual | ~QHelpSearchEngine()
QHelpSearchQueryWidget * | queryWidget()
QHelpSearchResultWidget * | resultWidget()
QString | searchInput() const
int | searchResultCount() const
QVector<QHelpSearchResult> | searchResults(int start, int end) const

## Public Slots

void | cancelIndexing()
void | cancelSearching()
void | reindexDocumentation()
void | search(const QString &searchInput)

## Signals

void | indexingFinished()
void | indexingStarted()
void | searchingFinished(int searchResultCount)
void | searchingStarted()

## Detailed Description

Before the search engine can be used, one has to instantiate at least a QHelpEngineCore object that needs to be passed to the search engines constructor. This is required as the search engine needs to be connected to the help engines setupFinished() signal to know when it can start to index documentation.

After starting the indexing process the signal indexingStarted() is emitted and on the end of the indexing process the indexingFinished() is emitted. To stop the indexing one can call cancelIndexing().

When the indexing process has finished, the search engine can be used to search through the index for a given term using the search() function. When the search input is passed to the search engine, the searchingStarted() signal is emitted. When the search finishes, the searchingFinished() signal is emitted. The search process can be stopped by calling cancelSearching().

If the search succeeds, searchingFinished() is called with the search result count to fetch the search results from the search engine. Calling the searchResults() function with a range returns a list of QHelpSearchResult objects within the range. The results consist of the document title and URL, as well as a snippet from the document that contains the best match for the search input.

To display the given search results use the QHelpSearchResultWidget or build up your own one if you need more advanced functionality. Note that the QHelpSearchResultWidget can not be instantiated directly, you must retrieve the widget from the search engine in use as all connections will be established for you by the widget itself.

## Member Function Documentation

### QHelpSearchEngine::QHelpSearchEngine(QHelpEngineCore *helpEngine, QObject *parent = nullptr)

Constructs a new search engine with the given parent. The search engine uses the given helpEngine to access the documentation that needs to be indexed. The QHelpEngine's setupFinished() signal is automatically connected to the QHelpSearchEngine's indexing function, so that new documentation will be indexed after the signal is emitted.

### `[slot]` void QHelpSearchEngine::cancelIndexing()

Stops the indexing process.

### `[slot]` void QHelpSearchEngine::cancelSearching()

Stops the search process.

### `[signal]` void QHelpSearchEngine::indexingFinished()

This signal is emitted when the indexing process is complete.

### `[signal]` void QHelpSearchEngine::indexingStarted()

This signal is emitted when indexing process is started.

### `[slot]` void QHelpSearchEngine::reindexDocumentation()

Forces the search engine to reindex all documentation files.

### `[slot]` void QHelpSearchEngine::search(const QString &searchInput)

Starts the search process using the given search phrase searchInput.

The phrase may consist of several words. By default, the search engine returns the list of documents that contain all the specified words. The phrase may contain any combination of the logical operators AND, OR, and NOT. The operator must be written in all capital letters, otherwise it will be considered a part of the search phrase.

If double quotation marks are used to group the words, the search engine will search for an exact match of the quoted phrase.

For more information about the text query syntax, see SQLite FTS5 Extension.

This function was introduced in Qt 5.9.

### `[signal]` void QHelpSearchEngine::searchingFinished(int searchResultCount)

This signal is emitted when the search process is complete. The search result count is stored in searchResultCount.

### `[signal]` void QHelpSearchEngine::searchingStarted()

This signal is emitted when the search process is started.

### `[virtual]` QHelpSearchEngine::~QHelpSearchEngine()

Destructs the search engine.

### QHelpSearchQueryWidget *QHelpSearchEngine::queryWidget()

Returns a widget to use as input widget. Depending on your search engine configuration you will get a different widget with more or less subwidgets.

### QHelpSearchResultWidget *QHelpSearchEngine::resultWidget()

Returns a widget that can hold and display the search results.

### QString QHelpSearchEngine::searchInput() const

Returns the phrase that was last searched for.

This function was introduced in Qt 5.9.

### int QHelpSearchEngine::searchResultCount() const

Returns the number of results the search engine found.

This function was introduced in Qt 5.9.

### QVector<QHelpSearchResult> QHelpSearchEngine::searchResults(int start, int end) const

Returns a list of search results within the range from the index specified by start to the index specified by end.

This function was introduced in Qt 5.9.