Struct AVMediaSelectionOption 

pub struct AVMediaSelectionOption { /* private fields */ }

Available on crate feature AVMediaSelectionGroup only.

AVMediaSelectionOption represents a specific option for the presentation of media within a group of options.

See also Apple’s documentation

Implementations

impl AVMediaSelectionOption

pub unsafe fn mediaType(&self) -> Retained<AVMediaType>

Available on crate feature AVMediaFormat only.

The media type of the media data, e.g. AVMediaTypeAudio, AVMediaTypeSubtitle, etc.

pub unsafe fn mediaSubTypes(&self) -> Retained<NSArray<NSNumber>>

The mediaSubTypes of the media data associated with the option.

An NSArray of NSNumbers carrying four character codes (of type FourCharCode) as defined in CoreAudioTypes.h for audio media and in CMFormatDescription.h for video media. Also see CMFormatDescriptionGetMediaSubType in CMFormatDescription.h for more information about media subtypes.

Note that if no information is available about the encoding of the media presented when a media option is selected, the value of mediaSubTypes will be an empty array. This can occur, for example, with streaming media. In these cases the value of mediaSubTypes should simply not be used as a criteria for selection.

pub unsafe fn hasMediaCharacteristic( &self, media_characteristic: &AVMediaCharacteristic, ) -> bool

Available on crate feature AVMediaFormat only.

Reports whether the media selection option includes media with the specified media characteristic.

• Parameter mediaCharacteristic: The media characteristic of interest, e.g. AVMediaCharacteristicVisual, AVMediaCharacteristicAudible, AVMediaCharacteristicLegible, etc.

• Returns: YES if the media selection option includes media with the specified characteristic, otherwise NO.

pub unsafe fn isPlayable(&self) -> bool

Indicates whether a media selection option is playable.

If the media data associated with the option cannot be decoded or otherwise rendered, playable is NO.

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

Indicates the RFC 4646 language tag associated with the option. May be nil.

pub unsafe fn locale(&self) -> Option<Retained<NSLocale>>

Indicates the locale for which the media option was authored.

Use -[NSLocale objectForKey:NSLocaleLanguageCode] to obtain the language code of the locale. See NSLocale.h for additional information.

pub unsafe fn commonMetadata(&self) -> Retained<NSArray<AVMetadataItem>>

Available on crate feature AVMetadataItem only.

Provides an array of AVMetadataItems for each common metadata key for which a value is available.

The array of AVMetadataItems can be filtered according to language via +[AVMetadataItem metadataItemsFromArray:filteredAndSortedAccordingToPreferredLanguages:], according to locale via +[AVMetadataItem metadataItemsFromArray:withLocale:], or according to key via +[AVMetadataItem metadataItemsFromArray:withKey:keySpace:]. Example: to obtain the name (or title) of a media selection option in any of the user’s preferred languages.

NSString *title = nil;
NSArray *titles = [AVMetadataItem metadataItemsFromArray:[mediaSelectionOption commonMetadata] withKey:AVMetadataCommonKeyTitle keySpace:AVMetadataKeySpaceCommon];
if ([titles count] > 0)
{
// Try to get a title that matches one of the user's preferred languages.
NSArray *titlesForPreferredLanguages = [AVMetadataItem metadataItemsFromArray:titles filteredAndSortedAccordingToPreferredLanguages:[NSLocale preferredLanguages]];
if ([titlesForPreferredLanguages count] > 0)
{
title = [[titlesForPreferredLanguages objectAtIndex:0] stringValue];
}

// No matches in any of the preferred languages. Just use the primary title metadata we find.
if (title == nil)
{
title = [[titles objectAtIndex:0] stringValue];
}
}

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

Provides an NSArray of NSStrings, each representing a metadata format that contains metadata associated with the option (e.g. ID3, iTunes metadata, etc.).

Metadata formats are defined in AVMetadataFormat.h.

pub unsafe fn metadataForFormat( &self, format: &NSString, ) -> Retained<NSArray<AVMetadataItem>>

Available on crate feature AVMetadataItem only.

Provides an NSArray of AVMetadataItems, one for each metadata item in the container of the specified format.

• Parameter format: The metadata format for which items are requested.

• Returns: An NSArray containing AVMetadataItems.

pub unsafe fn associatedMediaSelectionOptionInMediaSelectionGroup( &self, media_selection_group: &AVMediaSelectionGroup, ) -> Option<Retained<AVMediaSelectionOption>>

If a media selection option in another group is associated with the specified option, returns a reference to the associated option.

Audible media selection options often have associated legible media selection options; in particular, audible options are typically associated with forced-only subtitle options with the same locale. See AVMediaCharacteristicContainsOnlyForcedSubtitles in AVMediaFormat.h for a discussion of forced-only subtitles.

• Parameter mediaSelectionGroup: A media selection group in which an associated option is to be sought.

• Returns: An instance of AVMediaSelectionOption.

pub unsafe fn propertyList(&self) -> Retained<AnyObject>

Returns a serializable property list that can be used to obtain an instance of AVMediaSelectionOption representing the same option as the receiver via -[AVMediaSelectionGroup mediaSelectionOptionWithPropertyList:].

• Returns: A serializable property list that’s sufficient to identify the option within its group. For serialization utilities, see NSPropertyList.h.

pub unsafe fn displayNameWithLocale( &self, locale: &NSLocale, ) -> Retained<NSString>

Provides an NSString suitable for display.

May use this option’s common metadata, media characteristics and locale properties in addition to the provided locale to formulate an NSString intended for display. Will only consider common metadata with the specified locale.

• Parameter locale: Localize manufactured portions of the string using the specificed locale.

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

Provides an NSString suitable for display using the current system locale.

May use this option’s common metadata, media characteristics and locale properties in addition to the current system locale to formulate an NSString intended for display. In the event that common metadata is not available in the specified locale, displayName will fall back to considering locales with the multilingual (“mul”) then undetermined (“und”) locale identifiers. For a display name strictly with the specified locale use displayNameWithLocale: instead.

impl AVMediaSelectionOption

Methods declared on superclass NSObject.

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

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

Methods from Deref<Target = NSObject>

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

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());

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.

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`
    }
}

Trait Implementations

impl AsRef<AVMediaSelectionOption> for AVMediaSelectionOption

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<AnyObject> for AVMediaSelectionOption

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for AVMediaSelectionOption

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for AVMediaSelectionOption

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVMediaSelectionOption

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVMediaSelectionOption

const NAME: &'static str = "AVMediaSelectionOption"

The name of the Objective-C class that this type represents.

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVMediaSelectionOption as ClassType>::Super as ClassType>::ThreadKind

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl CopyingHelper for AVMediaSelectionOption

type Result = AVMediaSelectionOption

The immutable counterpart of the type, or Self if the type has no immutable counterpart.

impl Debug for AVMediaSelectionOption

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for AVMediaSelectionOption

type Target = NSObject

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for AVMediaSelectionOption

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for AVMediaSelectionOption

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSCopying for AVMediaSelectionOption

fn copy(&self) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

unsafe fn copyWithZone(&self, zone: *mut NSZone) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

impl NSObjectProtocol for AVMediaSelectionOption

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for AVMediaSelectionOption

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for AVMediaSelectionOption

const ENCODING_REF: Encoding = <NSObject as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for AVMediaSelectionOption

impl Eq for AVMediaSelectionOption