Camera2.Basic crashes when press button

[stevebroshar]

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Target: PIxel 7 API 34 simulator
Android Studio: 2023.1.1
Clicking button in Camera2Basic (to take pic?) crashes app.

2024-01-16 14:52:38.113 10412-10412 AndroidRuntime com.android.example.camera2.basic E FATAL EXCEPTION: main
Process: com.android.example.camera2.basic, PID: 10412
java.lang.NullPointerException
at com.example.android.camera2.basic.fragments.CameraFragment.getFragmentCameraBinding(CameraFragment.kt:79)
at com.example.android.camera2.basic.fragments.CameraFragment.access$getFragmentCameraBinding(CameraFragment.kt:74)
at com.example.android.camera2.basic.fragments.CameraFragment$animationTask$2.invoke$lambda-1$lambda-0(CameraFragment.kt:117)
at com.example.android.camera2.basic.fragments.CameraFragment$animationTask$2.$r8$lambda$kSaIYQrPru2VxvpYHL5tPwU4w3s(Unknown Source:0)
at com.example.android.camera2.basic.fragments.CameraFragment$animationTask$2$$ExternalSyntheticLambda1.run(Unknown Source:2)
at android.os.Handler.handleCallback(Handler.java:958)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:205)
at android.os.Looper.loop(Looper.java:294)
at android.app.ActivityThread.main(ActivityThread.java:8177)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

[stevebroshar]

I think the issue is the call to property fragmentCameraBinding via overlay.postDelayed. The property is defined as _fragmentCameraBinding!!, but in the delayed call sometimes the value is null -- probably due to clear in onDestroyView. I think a better implementation is using a lateinit field and no property:

private lateinit var fragmentCameraBinding: FragmentCameraBinding

I think the sweet spot for lateinit is exactly this scenario: a variable that is basically immutable but initialized after ctor.