Observable

Observe value changes. Similar to the ReactiveX Behavior Subject.

Important differences for Phenix SDK observables:

There is always an initial value (which can be nil for some objects)
Only if observed value changes will subscribers get notified

Point 1 means that when subscribing, you will always get notified immediately with the current value. This is guaranteed atomic, meaning that you do not have to worry about missing any observable updates.

PhenixObservable

Name	Signature	Returns	Description
subscribe	(onChanged)	PhenixDisposable	See Subscribe to an Observable
getValue	()	varies	See Get Observable Value
setValue	(value)	void	See Set Observable Value

Receive a notification every time the observable value changes.

Objective-C
@import PhenixSdk;

PhenixObservable<NSString*>* observable = ...;  // previously obtained

id<PhenixDisposable> subscription =
    [observable subscribe:^(PhenixObservableChange<NSString*>* change) {
        NSString* newStringValue = change.value;
        // Do something with newStringValue
      }];

// Releasing subscription will cancel it:
subscription = nil;

Swift
import PhenixSdk

let observable: PhenixObservable<String> = ...  // previously obtained

var subscription = observable.subscribe({ change in
    if let change = change, let newStringValue = change.value {
      // Do something with newStringValue
    })

// Releasing subscription will cancel it:
subscription = nil

Parameters

Name	Type	Description
onChanged (required)	Function	Function to call when value changes

PhenixDisposable

Has no methods. Dropping the last reference will automatically cancel the subscription.

Get Observable Value

Synchronous method allowing retrieval of currently set value. Thread safe.

Note: Since enums are not full objects, they are proxied via NSNumber.

Objective-C
@import PhenixSdk;

PhenixObservable<NSNumber*>* roleObservable = ...;  // previously obtained
PhenixMemberRole role = (PhenixMemberRole)[roleObservable getValue].intValue;

PhenixObservable<NSString*>* stringObservable = ...;  // previously obtained
NSString* stringValue = [stringObservable getValue];

Swift
import PhenixSdk

let roleObservable: PhenixObservable<NSNumber> = ...  // previously obtained
let role = PhenixMemberRole(rawValue: roleObservable.getValue().intValue)

let stringObservable: PhenixObservable<NSString> = ...  // previously obtained
let stringValue: String = stringObservable().getValue() as String

In swift, observables containing NSArray need to be cast further:

Swift
import PhenixSdk

let member: PhenixMember = ...  // previously obtained

let observable: PhenixObservable<NSArray> = (member.getObservableStreams())!
let streams: [PhenixStream] = observable.getValue() as! [PhenixStream]

Set Observable Value

Change the observable value. This will trigger notifications on all subscribers.

Enums require special attention when being set.

Objective-C
@import PhenixSdk;

PhenixObservable<NSNumber*>* roleObservable = ...;  // previously obtained
[roleObservable setValue:[NSNumber numberWithInt:PhenixMemberRolePresenter]];

PhenixObservable<NSString*>* stringObservable = ...;  // previously obtained
[stringObservable setValue:@"new value"];

Swift
import PhenixSdk

let roleObservable: PhenixObservable<NSNumber> = ...  // previously obtained
roleObservable.setValue(NSNumber(value: PhenixMemberRole.presenter.rawValue))

let stringObservable: PhenixObservable<NSString> = ...  // previously obtained
stringObservable.setValue("new value")

Page Content

v2023-09-12T20:09:36.000Z

Observable

PhenixObservable#Copied URL

Subscribe to an Observable#Copied URL

Parameters#Copied URL

PhenixDisposable#Copied URL

Get Observable Value#Copied URL

Set Observable Value#Copied URL

PhenixObservable

Subscribe to an Observable

Parameters

PhenixDisposable

Get Observable Value

Set Observable Value