Instance Method

initWithDocumentType:predicate:limit:sortDescriptors:includeDocumentData:resultsHandler:

Instantiates and returns a document query.

Declaration

- (instancetype)initWithDocumentType:(HKDocumentType *)documentType predicate:(NSPredicate *)predicate limit:(NSUInteger)limit sortDescriptors:(NSArray<NSSortDescriptor *> *)sortDescriptors includeDocumentData:(BOOL)includeDocumentData resultsHandler:(void (^)(HKDocumentQuery *query, NSArray<__kindof HKDocumentSample *> *results, BOOL done, NSError *error))resultsHandler;

Parameters

documentType

The type of document to search for. For a list of supported document types, see Document Type Identifier in HealthKit Constants.

predicate

A predicate that limits the results returned by the query. Pass nil to receive all the documents of the specified type.

limit

The maximum number of samples returned by the query. If you want to return all matching samples, use HKObjectQueryNoLimit.

sortDescriptors

An array of sort descriptors that specify the order of the results returned by this query. Pass nil if you don’t need the results in a specific order.

includeDocumentData

Pass YES to include the full document data. Pass NO to just receive a summary of the document. For CDA documents, the summary includes the title, the patient’s name, the author’s name, and the custodian’s name.

Since the full document data can be quite large, only pass YES when you need to access the full document’s data.

resultsHandler

A block that is called each time a new batch of documents is available. The document query returns its results incrementally in batches. The results handler may be called multiple times each time the query is executed.

This block takes the following parameters:

query

A reference to the query calling this block.

results

An array containing the samples returned by this query, or nil if an error occurred.

done

A Boolean value that indicates whether the query is done. If YES, the query is complete, and it will not call the results handler again. Otherwise, the query will call the results handler at least one more time, as soon as the next batch of documents is available.

error

If an error occurs, this parameter contains an object describing the error; otherwise, it is nil.

Return Value

A newly initialized document query object.

Discussion

After you instantiate the query, call the HKHealthStore class’s executeQuery: method to run it. Queries run on an anonymous background queue. As soon as the query is complete, the results handler is executed on the same background queue (but not necessarily on the same thread). You typically dispatch these results to the main queue to update the user interface.

See Also

Creating Document Queries

HKObjectQueryNoLimit

A value indicating that the query returns all the matching samples in the HealthKit store.