NPE on `FastScroller#computeHandlePosition`

java.lang.NullPointerException: Attempt to invoke virtual method
'android.view.View android.view.ViewGroup.getChildAt(int)' on a null object
reference
at
com.amaze.filemanager.ui.views.FastScroller.computeHandlePosition(FastScroller.java:73)
at
com.amaze.filemanager.ui.views.FastScroller.updateHandlePosition(FastScroller.java:251)
at
com.amaze.filemanager.ui.fragments.MainFragment.lambda$reloadListElements$8(MainFragment.java:912)
at
com.amaze.filemanager.ui.fragments.MainFragment.$r8$lambda$it2GteePdyxy4FeHs40lYdgdQMs(Unknown
Source:0)
at
com.amaze.filemanager.ui.fragments.MainFragment$$ExternalSyntheticLambda11.onOffsetChanged(Unknown
Source:2)
at
com.google.android.material.appbar.AppBarLayout.onOffsetChanged(AppBarLayout.java:886)
at
com.google.android.material.appbar.AppBarLayout$BaseBehavior.onLayoutChild(AppBarLayout.java:1827)
at
com.google.android.material.appbar.AppBarLayout$Behavior.onLayoutChild(AppBarLayout.java:1427)
at
com.google.android.material.appbar.AppBarLayout$BaseBehavior.onLayoutChild(AppBarLayout.java:1446)
at
androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:918)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at
androidx.drawerlayout.widget.DrawerLayout.onLayout(DrawerLayout.java:1263)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at android.widget.FrameLayout.layoutChildren(Unknown Source:160)
at android.widget.FrameLayout.onLayout(Unknown Source:6)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at android.widget.FrameLayout.layoutChildren(Unknown Source:160)
at android.widget.FrameLayout.onLayout(Unknown Source:6)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at android.widget.FrameLayout.layoutChildren(Unknown Source:160)
at android.widget.FrameLayout.onLayout(Unknown Source:6)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at android.widget.LinearLayout.setChildFrame(Unknown Source:4)
at android.widget.LinearLayout.layoutVertical(Unknown Source:184)
at android.widget.LinearLayout.onLayout(Unknown Source:5)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at android.widget.FrameLayout.layoutChildren(Unknown Source:160)
at android.widget.FrameLayout.onLayout(Unknown Source:6)
at com.android.internal.policy.DecorView.onLayout(Unknown Source:0)
at android.view.View.layout(Unknown Source:112)
at android.view.ViewGroup.layout(Unknown Source:21)
at android.view.ViewRootImpl.performLayout(Unknown Source:32)
at android.view.ViewRootImpl.performTraversals(Unknown Source:2370)
at android.view.ViewRootImpl.doTraversal(Unknown Source:36)
at android.view.ViewRootImpl$TraversalRunnable.run(Unknown Source:7)
at android.view.Choreographer$CallbackRecord.run(Unknown Source:20)
at android.view.Choreographer$CallbackRecord.run(Unknown Source:20)
at android.view.Choreographer.doCallbacks(Unknown Source:110)
at android.view.Choreographer.doFrame(Unknown Source:524)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Unknown
Source:40)
at android.os.Handler.handleCallback(Unknown Source:2)
at android.os.Handler.dispatchMessage(Unknown Source:4)
at android.os.Looper.loopOnce(Unknown Source:182)
at android.os.Looper.loop(Unknown Source:82)
at android.app.ActivityThread.main(Unknown Source:123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(Unknown
Source:11)
at com.android.internal.os.ZygoteInit.main(Unknown Source:312)