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HomeiOS DevelopmentExperimenting with Stay Actions – Ole Begemann

Experimenting with Stay Actions – Ole Begemann

iOS 16 beta 4 is the primary SDK launch that helps Stay Actions. A Stay 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 instances.

These are my notes on enjoying with the API and implementing my first Stay Exercise.

A motorbike laptop in your lock display screen

My Stay Exercise is a show for a motorcycle laptop that I’ve been creating with a gaggle a pals. 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 undertaking publicly but; that may hopefully change sometime. In brief, a gaggle of pals and I designed somewhat field that connects to your bike’s hub dynamo, measures pace and distance, and sends the info by way of Bluetooth to an iOS app. The app data all of your rides and may act as a dwell speedometer when mounted in your bike’s handlebar. It’s this final function that I wished to duplicate within the Stay Exercise.

Comply with Apple’s information

Including a Stay Exercise to the app wasn’t laborious. I discovered Apple’s information Displaying dwell knowledge on the Lock Display screen with Stay Actions straightforward to comply with and fairly complete.

No specific consumer approval

iOS doesn’t ask the consumer for approval when an app desires to point out a Stay Exercise. I discovered this odd because it appears to ask builders to abuse the function, however possibly it’s OK due to the foreground requirement (see beneath). Plus, customers can disallow Stay Actions on a per-app foundation in Settings.

Customers can dismiss an energetic Stay Exercise from the lock display screen by swiping (like a notification).

Most apps will most likely have to ask the consumer for notification permissions to replace their Stay Actions.

The app should be within the foreground to begin an exercise

To start out a Stay Exercise, an app should be open within the foreground. This isn’t excellent for the bike laptop as a result of the speedometer can’t seem magically on the lock display screen when the consumer begins driving (although iOS wakes up the app within the background at this level to ship the Bluetooth occasions from the bike). The consumer has to open the app manually no less than as soon as.

However, this limitation will not be a problem for many use circumstances and can most likely reduce down on spamming/abuse considerably.

The app should hold 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 may possibly replace the Stay Exercise as typically because it desires (I believe). That is excellent 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, equivalent to audio gamers or navigation apps doing steady location monitoring.

Updating the Stay Exercise as soon as per second was no downside in my testing, and I didn’t expertise any charge limiting.

Most apps get suspended within the background, nonetheless. They have to use push notifications to replace their Stay Exercise (or background duties or another mechanism to have the system wake you up). Apple launched a brand new sort of push notification that’s delivered on to the Stay 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 Stay Exercise from there. Most likely much less aggressive charge limiting?

Lock display screen shade matching

I haven’t discovered a great way to match my Stay Exercise’s colours to the present system colours on the lock display screen. By default, textual content in a Stay 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 may be an API or atmosphere worth that permits apps to match the colour model of the present lock display screen, I haven’t discovered it. I experimented with numerous foreground types, equivalent to supplies, with out success.

I ended up hardcoding the foreground shade, however I’m not happy with the end result. Relying on the consumer’s lock display screen theme, the Stay Exercise can look misplaced.

The lock screen of an iPhone running iOS 16. The system text (clock, date) is in a light, whitish color. The Live Activity at the bottom of the screen has black text.
The default textual content shade of a Stay Exercise in mild mode is black. This doesn’t match most lock display screen themes.

Animations can’t be disabled

Apple’s information clearly states that builders have little management over animations in a Stay Exercise:

Animate content material updates

Once you outline the consumer interface of your Stay Exercise, the system ignores any animation modifiers — for instance, withAnimation(_:_:) and animation(_:worth:) — and makes use of the system’s animation timing as an alternative. Nonetheless, the system performs some animation when the dynamic content material of the Stay Exercise modifications. Textual content views animate content material modifications with blurred content material transitions, and the system animates content material transitions for photos and SF Symbols. In case you add or take away views from the consumer interface based mostly on content material or state modifications, views fade out and in. Use the next view transitions to configure these built-in transitions: opacity, transfer(edge:), slide, push(from:), or mixtures of them. Moreover, request animations for timer textual content with numericText(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 Stay Actions into the always-on show that’s most likely approaching the following iPhone.

What stunned me is that I couldn’t discover a strategy to disable the textual content change animations altogether. I discover the blurred textual content transitions for the massive pace worth fairly distracting and I believe this label would look higher with none animations. However no mixture of .animation(nil), .contentTransition(.identification), and .transition(.identification) would do that.

A Stay Exercise may be very very similar to a widget: the UI should dwell in your app’s widget extension. You begin the Stay Exercise with code that runs in your app, although. Each targets (the app and the widget extension) want entry to a typical knowledge kind that represents the info 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 totally different minimal deployment targets. In case your widget extension has a deployment goal of iOS 14 or 15 for an current widget and also you now wish to add a Stay Exercise, I’d anticipate your widget bundle to appear like this:

@most important
struct MyWidgets: WidgetBundle {
  var physique: some Widget {
    // Error: Closure containing management move assertion can not
    // be used with end result builder 'WidgetBundleBuilder'
    if #obtainable(iOSApplicationExtension 16.0, *) {

However this doesn’t compile as a result of the end result builder kind utilized by WidgetBundle doesn’t help availability circumstances. 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 current widgets and may’t require iOS 16 but, a workaround is so as to add a second widget extension goal only for the Stay 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.



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