Struct HKSampleQuery

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pub struct HKSampleQuery { /* private fields */ }

Available on crate features HKQuery and HKSampleQuery only.

Expand description

Apple’s documentation

Implementations§

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impl HKSampleQuery

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pub unsafe fn limit(&self) -> NSUInteger

The maximum number of results 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 initWithSampleType_predicate_limit_sortDescriptors_resultsHandler( this: Allocated<Self>, sample_type: &HKSampleType, predicate: Option<&NSPredicate>, limit: NSUInteger, sort_descriptors: Option<&NSArray<NSSortDescriptor>>, results_handler: &DynBlock<dyn Fn(NonNull<HKSampleQuery>, mut NSArray<HKSample>, mut NSError)>, ) -> Retained<Self>

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

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

Parameter sampleType: The type of sample to retrieve.

Parameter predicate: The predicate which samples should match.

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

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

Parameter resultsHandler: The block to invoke with results when the query has finished executing.

§Safety

results_handler block must be sendable.

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pub unsafe fn initWithQueryDescriptors_limit_resultsHandler( this: Allocated<Self>, query_descriptors: &NSArray<HKQueryDescriptor>, limit: NSInteger, results_handler: &DynBlock<dyn Fn(NonNull<HKSampleQuery>, mut NSArray<HKSample>, mut NSError)>, ) -> Retained<Self>

Available on crate features HKObject and HKQueryDescriptor and HKSample and block2 only.

Returns a query that will retrieve HKSamples matching any of the given queryDescriptors.

Parameter queryDescriptors: An array of query descriptors that describes the sample types and predicates used for querying.

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

Parameter resultsHandler: The block to invoke with results when the query has finished executing. This block is invoked once with results, an array of HKSamples matching the queryDescriptors passed in, or nil if an error occurred.

§Safety

results_handler block must be sendable.

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pub unsafe fn initWithQueryDescriptors_limit_sortDescriptors_resultsHandler( this: Allocated<Self>, query_descriptors: &NSArray<HKQueryDescriptor>, limit: NSInteger, sort_descriptors: &NSArray<NSSortDescriptor>, results_handler: &DynBlock<dyn Fn(NonNull<HKSampleQuery>, mut NSArray<HKSample>, mut NSError)>, ) -> Retained<Self>

Available on crate features HKObject and HKQueryDescriptor and HKSample and block2 only.

Returns a query that will retrieve HKSamples matching any of the given queryDescriptors.

Parameter queryDescriptors: An array of query descriptors that describes the sample types and predicates used for querying.

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

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

Parameter resultsHandler: The block to invoke with results when the query has finished executing. This block is invoked once with results, an array of HKSamples matching the queryDescriptors passed in, or nil if an error occurred. The HKSamples in the array are sorted by the specified sortDescriptors.

§Safety

results_handler block must be sendable.

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impl HKSampleQuery

Methods declared on superclass HKQuery.

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

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impl HKSampleQuery

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`
    }
}