Android: Fix crash when WindowInsets is null on ReactRootView

[enahum]

Summary

Fixes a potential crash was introduced by #30919 that aimed to get the keyboard height on devices with a Notch. The problem is that it considers that any ReactRootView will have an insets available.

When using react-native-navigation and assigning a Navigation button to the TopBar as a component, the component gets registered as a RootView but won't have any insets attach to the view.

getRootWindowInsets() in fact return a WindowInset only available if the view is attached, so when executing checkForKeyboardEvents method from ReactRootView, is trying to access the DisplayCutout of a null object, leading to a crash.

Changelog

[Android] [Fixed] - Fix potential crash if ReactRootView does not have insets attached.

Test Plan

Without the code change: Notice how the second screen being push contains a React Component on the top right of the navigation bar, and when component is unmounted (going back) the app crashes.

rn67-crash.1.mp4

crash log

2022-01-28 10:27:52.902 15600-15600/com.mattermost.rnbeta E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.mattermost.rnbeta, PID: 15600
    java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.DisplayCutout android.view.WindowInsets.getDisplayCutout()' on a null object reference
        at com.facebook.react.ReactRootView$CustomGlobalLayoutListener.checkForKeyboardEvents(ReactRootView.java:778)
        at com.facebook.react.ReactRootView$CustomGlobalLayoutListener.onGlobalLayout(ReactRootView.java:769)
        at android.view.ViewTreeObserver.dispatchOnGlobalLayout(ViewTreeObserver.java:1061)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:3214)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:2143)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8665)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1037)
        at android.view.Choreographer.doCallbacks(Choreographer.java:845)
        at android.view.Choreographer.doFrame(Choreographer.java:780)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1022)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7839)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)

After applying the patch which is only a null check validation and does not change any previous behavior

rn67-fix.1.mp4

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 384e1a0
Branch: main

[cortinico]

Change looks sane to me. Also from the documentation:
https://developer.android.com/reference/android/view/View#getRootWindowInsets()

WindowInsets from the top of the view hierarchy or null if View is detached

[cortinico]

Indentation is odd here

[enahum]

indentation fixed ;)

[cortinico]

nit: That's why we need Kotlin :)

[ShikaSD]

...and million other reasons too 😅

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,297,729	-2,673
android	hermes	armeabi-v7a	7,634,842	-4,100
android	hermes	x86	8,771,019	-4,829
android	hermes	x86_64	8,708,089	-4,668
android	jsc	arm64-v8a	9,783,495	-1,340
android	jsc	armeabi-v7a	8,768,801	-1,920
android	jsc	x86	9,749,365	-2,095
android	jsc	x86_64	10,345,314	-2,313

Base commit: 384e1a0
Branch: main

[facebook-github-bot]

@ShikaSD has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[react-native-bot]

This pull request was successfully merged by @enahum in 6239e2f.

^{When will my fix make it into a release? | Upcoming Releases}