Struct AVAudioApplication

Source

pub struct AVAudioApplication { /* private fields */ }

Available on crate feature AVAudioApplication only.

Expand description

Class containing methods that relate to an application bundle’s audio (i.e. a collection of one or more AVAudioSession instances)

Implementations§

Source §

impl AVAudioApplication

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pub unsafe fn sharedInstance() -> Retained<AVAudioApplication>

Returns the singleton instance

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

See: sharedInstance

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pub unsafe fn setInputMuted_error( &self, muted: bool, ) -> Result<(), Retained<NSError>>

Set the muted/unmuted state of the application’s audio input. When set true, inputs (microphone etc.) of all audio clients relating to this application will have their samples zeroed out.

Note: - this is per-application input muting and doesn’t affect the hardware mute state.

Source

pub unsafe fn isInputMuted(&self) -> bool

Get the input muted state - return value is boolean 0 for unmuted or value 1 for muted (input samples zeroed out)

This property is not atomic.

§Safety

This might not be thread-safe.

Source

pub unsafe fn setInputMuteStateChangeHandler_error( &self, input_mute_handler: Option<&DynBlock<dyn Fn(Bool) -> Bool>>, ) -> Result<(), Retained<NSError>>

Available on crate feature block2 only.

Provide a block that implements your app’s input (microphone) muting logic (macOS only). The block will be called whenever the input mute state changes, either due to changing the AVAudioApplication.inputMute property on this API, or due to a Bluetooth audio accessory gesture (certain AirPods / Beats headphones) changing the mute state.

Parameter inputMuteHandler: block that will be called upon every input mute state change. If the boolean inputShouldBeMuted is true, your block should mute all input/microphone samples until the next time the handler is called. Your block should return a value of YES if successful, or in exceptional cases return a NO value if the mute action was unsuccesful. Since the input mute handling logic should happen a single place, subsequent calls to this method will overwrite any previously registered block with the one provided. A nil value may be provided to cancel the block being called, e.g. at end of call lifecycle.

Note: This is available on macOS only - for all other platforms input muting will be handled internally. It is recommended only to perform your input muting logic within this block, and to perform your UI updates for input mute state changes within the handler for AVAudioApplicationInputMuteStateChangeNotification. This handler should be set by the process doing the call’s audio I/O.

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pub unsafe fn recordPermission(&self) -> AVAudioApplicationRecordPermission

Returns an enum indicating whether the user has granted or denied permission to record, or has not been asked

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pub unsafe fn requestRecordPermissionWithCompletionHandler( response: &DynBlock<dyn Fn(Bool)>, )

Available on crate feature block2 only.

Checks to see if calling process has permission to record audio.

The ‘response’ block will be called immediately if permission has already been granted or denied. Otherwise, it presents a dialog to notify the user and allow them to choose, and calls the block once the UI has been dismissed. ‘granted’ indicates whether permission has been granted. Note that the block may be called in a different thread context.

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pub unsafe fn microphoneInjectionPermission( &self, ) -> AVAudioApplicationMicrophoneInjectionPermission

Returns an enum indicating whether the user has granted or denied permission to inject audio into input, or has not been asked

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pub unsafe fn requestMicrophoneInjectionPermissionWithCompletionHandler( response: &DynBlock<dyn Fn(AVAudioApplicationMicrophoneInjectionPermission)>, )

Available on crate feature block2 only.

Checks to see if calling process has permission to inject audio to input stream.

The ‘response’ block will be called immediately if permission has already been granted or denied or if the service is disabled by the user. Otherwise, it presents a dialog to notify the user and allow them to choose, and calls the block once the UI has been dismissed. ‘granted’ indicates whether permission has been granted. Note that the block may be called in a different thread context.

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impl AVAudioApplication

Methods declared on superclass NSObject.

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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.

Source

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`
    }
}