Struct HKDocumentQuery

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pub struct HKDocumentQuery { /* private fields */ }

Available on crate features HKDocumentQuery and HKQuery only.

Expand description

A concrete subclass of HKQuery that provides an interface to retrieve documents from the Health store.

Implementations§

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impl HKDocumentQuery

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pub unsafe fn limit(&self) -> NSUInteger

The maximum number of documents the receiver will return upon completion.

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pub unsafe fn sortDescriptors( &self, ) -> Option<Retained<NSArray<NSSortDescriptor>>>

An array of NSSortDescriptors.

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pub unsafe fn includeDocumentData(&self) -> bool

The XML content for documents may be large. This property can be used to control whether the query returns the XML content for each record.

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pub unsafe fn initWithDocumentType_predicate_limit_sortDescriptors_includeDocumentData_resultsHandler( this: Allocated<Self>, document_type: &HKDocumentType, predicate: Option<&NSPredicate>, limit: NSUInteger, sort_descriptors: Option<&NSArray<NSSortDescriptor>>, include_document_data: bool, results_handler: &DynBlock<dyn Fn(NonNull<HKDocumentQuery>, mut NSArray<HKDocumentSample>, Bool, mut NSError)>, ) -> Retained<Self>

Available on crate features HKDocumentSample and HKObject and HKObjectType and HKSample and block2 only.

Returns a query that will retrieve HKDocumentSamples matching the given predicate.

Parameter documentType: The type of document to retreive.

Parameter predicate: The predicate which documents should match.

Parameter limit: The maximum number of documents to return. Pass HKObjectQueryNoLimit for no limit.

Parameter sortDescriptors: The sort descriptors to use to order the resulting documents.

Parameter includeDocumentData: If true, the document content will be returned with the HKDocumentSample instance. This option can be used to limit the size of the content returned since the content may be large.

Parameter resultsHandler: The block that will receive query results. Results will be returned incrementally through several calls to this block. When there are no more results, the done parameter will be YES and the results array will be empty. If results is nil, then an error has occurred and the error parameter will be set. Delivery of results can be stopped by calling HKHealthStore’s stopQuery: method.

Health documents may contain sensitive data that a user may want to control explicitly. HKDocumentSample objects returned by HKSampleQuery and HKAnchoredObjectQuery do not include this data (i.e., the document property is nil). This query can be used to retrieve fully populated HKDocumentSample instances. The query will prompt the user to authorize your app to read individual documents. The query will then return the documents that your app is authorized to read. The user will only be asked to authorize your app to read documents that are new since the last time an HKDocumentQuery was executed.

§Safety

results_handler block must be sendable.

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impl HKDocumentQuery

Methods declared on superclass HKQuery.

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pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

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impl HKDocumentQuery

Methods declared on superclass NSObject.

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pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = HKQuery>§

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pub unsafe fn objectType(&self) -> Option<Retained<HKObjectType>>

Available on crate feature HKObjectType only.

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pub unsafe fn sampleType(&self) -> Option<Retained<HKSampleType>>

👎Deprecated

Available on crate feature HKObjectType only.

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pub unsafe fn predicate(&self) -> Option<Retained<NSPredicate>>

Methods from Deref<Target = NSObject>§

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pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

§Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

§Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

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pub unsafe fn get_ivar<T>(&self, name: &str) -> &T
where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

§Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

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pub fn downcast_ref<T>(&self) -> Option<&T>
where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

§Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

§Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

§Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

§Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}