Struct MPContentItem

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

Available on crate feature MPContentItem only.

Expand description

MPContentItem represents high-level metadata for a particular media item for representation outside the client application. Examples of media items that a developer might want to represent include song files, streaming audio URLs, or radio stations.

Implementations§

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impl MPContentItem

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

Designated initializer. A unique identifier is required to identify the item for later use.

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

A unique identifier for this content item. (Required)

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

A title for this item. Usually this would be the track name, if representing a song, the episode name of a podcast, etc.

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

Setter for title.

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

A subtitle for this item. If this were representing a song, this would usually be the artist or composer.

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

Setter for subtitle.

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pub unsafe fn artwork(&self) -> Option<Retained<MPMediaItemArtwork>>

Available on crate feature MPMediaItem only.

Artwork for this item. Examples of artwork for a content item are the album cover for a song, or a movie poster for a movie.

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pub unsafe fn setArtwork(&self, artwork: Option<&MPMediaItemArtwork>)

Available on crate feature MPMediaItem only.

Setter for artwork.

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pub unsafe fn playbackProgress(&self) -> c_float

Represents the current playback progress of the item. 0.0 = not watched/listened/viewed, 1.0 = fully watched/listened/viewed Default is -1.0 (no progress indicator shown)

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pub unsafe fn setPlaybackProgress(&self, playback_progress: c_float)

Setter for playbackProgress.

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pub unsafe fn isStreamingContent(&self) -> bool

Represents whether this content item is streaming content, i.e. from the cloud where the content is not stored locally.

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pub unsafe fn setStreamingContent(&self, streaming_content: bool)

Setter for isStreamingContent.

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pub unsafe fn isExplicitContent(&self) -> bool

Represents whether this content item is explicit content

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pub unsafe fn setExplicitContent(&self, explicit_content: bool)

Setter for isExplicitContent.

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pub unsafe fn isContainer(&self) -> bool

Represents whether the content item is a container that may contain other content items, e.g. an album or a playlist.

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pub unsafe fn setContainer(&self, container: bool)

Setter for isContainer.

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pub unsafe fn isPlayable(&self) -> bool

Represents whether the content item is actionable from a playback perspective. Albums are playable, for example, because selecting an album for playback means the app should play each song in the album in order. An example of a content item that may not be playable is a genre, since an app experience typically doesn’t involve selecting an entire genre for playback.

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pub unsafe fn setPlayable(&self, playable: bool)

Setter for isPlayable.

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impl MPContentItem

Methods declared on superclass NSObject.

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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 = 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`
    }
}