Struct AVAssetWriterInputGroup

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#[repr(C)]
pub struct AVAssetWriterInputGroup { /* private fields */ }

Available on crate features AVAssetWriter and AVMediaSelectionGroup only.

Expand description

Apple’s documentation

Implementations§

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pub unsafe fn assetWriterInputGroupWithInputs_defaultInput( inputs: &NSArray<AVAssetWriterInput>, default_input: Option<&AVAssetWriterInput>, ) -> Retained<Self>

Available on crate feature AVAssetWriterInput only.

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pub unsafe fn initWithInputs_defaultInput( this: Allocated<Self>, inputs: &NSArray<AVAssetWriterInput>, default_input: Option<&AVAssetWriterInput>, ) -> Retained<Self>

Available on crate feature AVAssetWriterInput only.

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pub unsafe fn inputs(&self) -> Retained<NSArray<AVAssetWriterInput>>

Available on crate feature AVAssetWriterInput only.

The inputs grouped together by the receiver.

The value of this property is an NSArray containing concrete instances of AVAssetWriterInput.

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pub unsafe fn defaultInput(&self) -> Option<Retained<AVAssetWriterInput>>

Available on crate feature AVAssetWriterInput only.

The input designated at the defaultInput of the receiver.

The value of this property is a concrete instance of AVAssetWriterInput.

Methods from Deref<Target = AVMediaSelectionGroup>§

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pub unsafe fn options(&self) -> Retained<NSArray<AVMediaSelectionOption>>

A collection of mutually exclusive media selection options.

An NSArray of AVMediaSelectionOption*.

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pub unsafe fn defaultOption(&self) -> Option<Retained<AVMediaSelectionOption>>

Indicates the default option in the group, i.e. the option that’s intended for use in the absence of a specific end-user selection or preference.

Can be nil, indicating that without a specific end-user selection or preference, no option in the group is intended to be selected.

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pub unsafe fn allowsEmptySelection(&self) -> bool

Indicates whether it’s possible to present none of the options in the group when an associated AVPlayerItem is played.

If allowsEmptySelection is YES, all of the available media options in the group can be deselected by passing nil as the specified AVMediaSelectionOption to -[AVPlayerItem selectMediaOption:inMediaSelectionGroup:].

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pub unsafe fn mediaSelectionOptionWithPropertyList( &self, plist: &AnyObject, ) -> Option<Retained<AVMediaSelectionOption>>

Returns the instance of AVMediaSelectionOption with properties that match the specified property list.

Parameter plist: A property list previously obtained from an option in the group via -[AVMediaSelectionOption propertyList].

Returns: If the specified properties match those of an option in the group, an instance of AVMediaSelectionOption. Otherwise nil.

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.

§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`
    }
}