Struct BGContinuedProcessingTaskRequest

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pub struct BGContinuedProcessingTaskRequest { /* private fields */ }

Available on crate feature BGTaskRequest only.

Expand description

A request to begin a workload immediately, or shortly after submission, which is allowed to continue running even if the app is backgrounded.

Implementations§

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impl BGContinuedProcessingTaskRequest

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pub unsafe fn title(&self) -> Retained<NSString>

The localized title displayed to the user.

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pub unsafe fn setTitle(&self, title: &NSString)

Setter for title.

This is copied when set.

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pub unsafe fn subtitle(&self) -> Retained<NSString>

The localized subtitle displayed to the user.

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pub unsafe fn setSubtitle(&self, subtitle: &NSString)

Setter for subtitle.

This is copied when set.

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pub unsafe fn strategy( &self, ) -> BGContinuedProcessingTaskRequestSubmissionStrategy

The submission strategy for the scheduler to abide by.

Defaults to BGContinuedProcessingTaskRequestSubmissionStrategy/BGContinuedProcessingTaskRequestSubmissionStrategyQueue.

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pub unsafe fn setStrategy( &self, strategy: BGContinuedProcessingTaskRequestSubmissionStrategy, )

Setter for strategy.

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pub unsafe fn requiredResources( &self, ) -> BGContinuedProcessingTaskRequestResources

Inform the scheduler that the task will be requesting additional system resources.

Defaults to BGContinuedProcessingTaskRequestResources/BGContinuedProcessingTaskRequestResourcesDefault.

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pub unsafe fn setRequiredResources( &self, required_resources: BGContinuedProcessingTaskRequestResources, )

Setter for requiredResources.

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pub unsafe fn initWithIdentifier_title_subtitle( this: Allocated<Self>, identifier: &NSString, title: &NSString, subtitle: &NSString, ) -> Retained<Self>

Creates an instance on behalf of the currently foregrounded app.

Apps and their extensions should use this method to initialize any tasks due to the underlying association to the currently foregrounded app. Please note that BGTaskRequest/earliestBeginDate will be outright ignored by the scheduler in favor of NSDate.now.

The identifier ought to use wildcard notation, where the prefix of the identifier must at least contain the bundle ID of the submitting application, followed by optional semantic context, and finally ending with .*. An example: ` <MainBundle

. <SemanticContext .which would transform tocom.foo.MyApplication.continuedProcessingTask.. Thus, a submitted identifier would be of the form com.foo.MyApplication.continuedProcessingTask.HD830D`.

Parameters:
identifier: The task identifier.
title: The localized title displayed to the user before the task begins running.
subtitle: The localized subtitle displayed to the user before the task begins running.
Warning: Successful creation of this object does not guarantee successful submission to the scheduler.

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impl BGContinuedProcessingTaskRequest

Methods declared on superclass BGTaskRequest.

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

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

Methods from Deref<Target = BGTaskRequest>§

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pub unsafe fn identifier(&self) -> Retained<NSString>

The identifier of the task associated with the request.

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pub unsafe fn earliestBeginDate(&self) -> Option<Retained<NSDate>>

The earliest date and time at which to run the task.

Specify nil for no start delay.

Setting the property indicates that the background task shouldn’t start any earlier than this date. However, the system doesn’t guarantee launching the task at the specified date, but only that it won’t begin sooner.

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pub unsafe fn setEarliestBeginDate(&self, earliest_begin_date: Option<&NSDate>)

Setter for earliestBeginDate.

This is copied when set.

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`
    }
}