iOS 16 beta 4 is the primary SDK launch that helps Reside Actions. A Reside Exercise is a widget-like view an app can place in your lock display screen and replace in actual time. Examples the place this may be helpful embrace dwell sports activities scores or prepare departure occasions.
These are my notes on enjoying with the API and implementing my first Reside Exercise.
A motorcycle laptop in your lock display screen
My Reside Exercise is a show for a motorbike laptop that I’ve been growing with a gaggle a mates. Right here’s a video of it in motion:
And right here with simulated knowledge:
I haven’t talked a lot about our bike laptop venture publicly but; that may hopefully change sometime. In brief, a gaggle of mates and I designed slightly field that connects to your bike’s hub dynamo, measures velocity and distance, and sends the information through Bluetooth to an iOS app. The app data all of your rides and also can act as a dwell speedometer when mounted in your bike’s handlebar. It’s this final characteristic that I needed to duplicate within the Reside Exercise.
Observe Apple’s information
Including a Reside Exercise to the app wasn’t onerous. I discovered Apple’s information Displaying dwell knowledge on the Lock Display screen with Reside Actions simple to comply with and fairly complete.
No express person approval
iOS doesn’t ask the person for approval when an app desires to point out a Reside Exercise. I discovered this odd because it appears to ask builders to abuse the characteristic, however possibly it’s OK due to the foreground requirement (see beneath). Plus, customers can disallow Reside Actions on a per-app foundation in Settings.
Customers can dismiss an energetic Reside Exercise from the lock display screen by swiping (like a notification).
Most apps will in all probability have to ask the person for notification permissions to replace their Reside Actions.
The app should be within the foreground to begin an exercise
To begin a Reside Exercise, an app should be open within the foreground. This isn’t perfect for the bike laptop as a result of the speedometer can’t seem magically on the lock display screen when the person begins using (regardless that iOS wakes up the app within the background at this level to ship the Bluetooth occasions from the bike). The person has to open the app manually a minimum of as soon as.
However, this limitation is probably not a difficulty for many use circumstances and can in all probability reduce down on spamming/abuse considerably.
The app should maintain working within the background to replace the exercise (or use push notifications)
So long as the app retains working (within the foreground or background), it could replace the Reside Exercise as usually because it desires (I feel). That is perfect for the bike laptop because the app retains working within the background processing Bluetooth occasions whereas the bike is in movement. I assume the identical applies to different apps that may stay alive within the background, corresponding to audio gamers or navigation apps doing steady location monitoring.
Updating the Reside Exercise as soon as per second was no downside in my testing, and I didn’t expertise any fee limiting.
Most apps get suspended within the background, nevertheless. They have to use push notifications to replace their Reside Exercise (or background duties or another mechanism to have the system wake you up). Apple launched a brand new form of push notification that’s delivered on to the Reside Exercise, bypassing the app altogether. I haven’t performed with push notification updates, so I don’t know the advantages of utilizing this methodology over sending a silent push notification to wake the app and updating the Reside Exercise from there. Most likely much less aggressive fee limiting?
Lock display screen shade matching
I haven’t discovered a great way to match my Reside Exercise’s colours to the present system colours on the lock display screen. By default, textual content in a Reside Exercise is black in mild mode, whereas the built-in lock display screen themes appear to favor white or different mild textual content colours. If there’s an API or surroundings worth that enables apps to match the colour fashion of the present lock display screen, I haven’t discovered it. I experimented with varied foreground kinds, corresponding to supplies, with out success.
I ended up hardcoding the foreground shade, however I’m not happy with the end result. Relying on the person’s lock display screen theme, the Reside Exercise can look misplaced.
Animations can’t be disabled
Apple’s information clearly states that builders have little management over animations in a Reside Exercise:
Animate content material updates
If you outline the person interface of your Reside Exercise, the system ignores any animation modifiers — for instance,
withAnimation(_:_:)andanimation(_:worth:)— and makes use of the system’s animation timing as an alternative. Nevertheless, the system performs some animation when the dynamic content material of the Reside Exercise adjustments. Textual content views animate content material adjustments with blurred content material transitions, and the system animates content material transitions for pictures and SF Symbols. In case you add or take away views from the person interface based mostly on content material or state adjustments, views fade out and in. Use the next view transitions to configure these built-in transitions:opacity,transfer(edge:),slide,push(from:), or combos of them. Moreover, request animations for timer textual content withnumericText(countsDown:).
It makes complete sense to me that Apple doesn’t need builders to go loopy with animations on the lock display screen, and maybe having full management over animations additionally makes it simpler for Apple to combine Reside Actions into the always-on show that’s in all probability approaching the following iPhone.
What stunned me is that I couldn’t discover a method to disable the textual content change animations altogether. I discover the blurred textual content transitions for the massive velocity worth fairly distracting and I feel this label would look higher with none animations. However no mixture of .animation(nil), .contentTransition(.id), and .transition(.id) would do that.
A Reside Exercise could be very very like a widget: the UI should dwell in your app’s widget extension. You begin the Reside Exercise with code that runs in your app, although. Each targets (the app and the widget extension) want entry to a standard knowledge kind that represents the information the widget shows. It’s best to have a 3rd goal (a framework or SwiftPM bundle) that comprises such shared varieties and APIs and that the downstream targets import.
Availability annotations
WidgetBundle apparently doesn’t help widgets with completely different minimal deployment targets. In case your widget extension has a deployment goal of iOS 14 or 15 for an present widget and also you now wish to add a Reside Exercise, I’d anticipate your widget bundle to seem like this:
@major
struct MyWidgets: WidgetBundle {
var physique: some Widget {
MyNormalWidget()
// Error: Closure containing management stream assertion can't
// be used with end result builder 'WidgetBundleBuilder'
if #obtainable(iOSApplicationExtension 16.0, *) {
MyLiveActivityWidget()
}
}
}
However this doesn’t compile as a result of the end result builder kind utilized by WidgetBundle doesn’t help availability situations. I hope Apple fixes this.
This wasn’t an issue for me as a result of our app didn’t have any widgets till now, so I simply set the deployment goal of the widget extension to iOS 16.0. When you’ve got present widgets and may’t require iOS 16 but, a workaround is so as to add a second widget extension goal only for the Reside Exercise. I haven’t tried this, however WidgetKit explicitly helps having a number of widget extensions, so it ought to work:
Usually, you embrace all of your widgets in a single widget extension, though your app can include a number of extensions.