Pause rendering when entering background #1086
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evil159
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…in iOS 13+ and falls back to older tech when running on older iOS versions
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| func testCarPlayWindowReturnsCorrectParentScene() { | ||
| let window = CPWindow() | ||
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| XCTAssertEqual(window.parentScene, window.templateApplicationScene) |
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What are the actual values? Are they both nil? If so, that might not be a very good test.
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Yeah, it's tricky to create a good test setup here as it is not possible to create a UIScene object(including its decendant CPTemplateApplicationScene. In this test indeed the expectation is that both of these values are nil.
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Not for this PR, but I wonder whether we could set up a test suite that runs in a host app with CarPlay entitlements.
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Good point, this will enable for tests like this to be run properly, let's get back to it next time we touch CarPlay related stuff.
Tests/MapboxMapsTests/Foundation/Extensions/UIWindow+ParentSceneTests.swift
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Tests/MapboxMapsTests/Foundation/Extensions/UIWindow+ParentSceneTests.swift
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| var notificationCenter: MockNotificationCenter! | ||
| var bundle: MockBundle! |
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Please nil these in tearDown
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notificationCenter too please
| let notificationCenter = MockNotificationCenter() | ||
| let bundle = MockBundle() | ||
| bundle.infoDictionaryStub.defaultReturnValue = [:] | ||
| dependencyProvider.makeNotificationCenterStub.defaultReturnValue = notificationCenter | ||
| dependencyProvider.makeBundleStub.defaultReturnValue = bundle | ||
| let mapView = MapView( | ||
| frame: CGRect(origin: .zero, size: CGSize(width: 100, height: 100)), | ||
| mapInitOptions: MapInitOptions(), | ||
| dependencyProvider: dependencyProvider) | ||
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| window.addSubview(mapView) |
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Is this necessary? seems to duplicate what's already happening in setUp
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Similarly in the other tests.
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I setup a new instance of MapView here so I can affect which lifecycle notifications map view subscribes to(by altering bundle's infoDictionaryStub). In this particular test there is no need to have this setup here as it matches with the one from setUp. I put it here for consistency with testSceneLifecycleNotificationSubscribedWhenDidMoveToNewWindow.
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| @available(iOS 13.0, *) | ||
| @objc private func sceneWillEnterForeground(_ notification: Notification) { | ||
| guard notification.object as? UIScene == window?.parentScene else { return } |
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I don't think these checks are necessary since we only subscribe for a specific object.
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Removing them would allow you to share handlers with the app lifecycle notifications
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I added them here to protect from a situation when map view moves to a window without scene attached(there is no clear documentation on specifics of this, so I'm assuming it's possible). The map view will subscribe to lifecycle notifications with nil object in this case. And this check supposed to be a safeguard against it.
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So the scenario is, on iOS 13+ with scenes enabled, map view moves to a window that has a nil scene?
In that case, we would basically not get pausing and resuming until the window's scene became non-nil, right?
Not sure if this scenario is even possible.
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Yeah, in this scenario we won't get pausing and resuming, it either this or pausing and resuming by notifications from a random scene(if there would be no checks). But this scenario is definitely in the realm of possibility - windowScene is an optional readwrite property.
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Approving, but can you take care of one more thing before merging? #1086 (comment)
Nice work!
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| notificationCenter.addObserver(self, | ||
| selector: #selector(appWillEnterForeground), | ||
| name: UIApplication.willEnterForegroundNotification, | ||
| object: nil) |
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Per mapbox/mapbox-gl-native#1869, this may be too early for mbgl to wake up and start rendering again:
UIApplicationWillEnterForegroundNotification is posted before UIApplicationDidBecomeActiveNotification, while the application is still in the background.
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#1402 replaces this with UIScene.didActivateNotification.
| notificationCenter.addObserver(self, | ||
| selector: #selector(sceneWillEnterForeground(_:)), | ||
| name: UIScene.willEnterForegroundNotification, | ||
| object: window?.parentScene) |
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As with UIApplication.willEnterForegroundNotification, UIScene.willEnterForegroundNotification is probably premature as well. UIScene.didActivateNotification would be more reliable.
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#1402 replaces this with UIApplication.didBecomeActiveNotification.
MapViewwill now listen to eitherUIApplicationorUIScenelifecycle event notifications(depending on project setup). As application/scene moves to background/foreground, map view'sdisplayLinkwill be paused/resumed accordingly.On iOS 11 and 12
UIApplicationis the only source of these events. Starting from iOS 13 Scene API can be enabled by including UIApplicationSceneManifest key toInfo.plist.Additionally this PR adds
reduceMemoryUse()call when transitioning to background as its documentation advises.Fixes #978, #1053
Pull request checklist:
## mainheading near the top).