Just before lunch my Android app in my .NET Standard Xamarin Forms was working 
After lunch without any changes it's crashing 
I am getting this error:
Java.Lang.NullPointerException: Attempt to invoke virtual method 'void android.app.Activity.requestPermissions(java.lang.String[], int)' on a null object reference
at java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.Activity.requestPermissions(java.lang.String[], int)' on a null object reference
at at android.support.v4.app.ActivityCompat.requestPermissions(ActivityCompat.java:479)
at at md58432a647068b097f9637064b8985a5e0.NavigationPageRenderer.n_onAttachedToWindow(Native Method)
at at md58432a647068b097f9637064b8985a5e0.NavigationPageRenderer.onAttachedToWindow(NavigationPageRenderer.java:49)
at at android.view.View.dispatchAttachedToWindow(View.java:15395)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2953)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2960)
at at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1516)
at at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246)
at at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6301)
at at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
at at android.view.Choreographer.doCallbacks(Choreographer.java:683)
at at android.view.Choreographer.doFrame(Choreographer.java:619)
at at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
at at android.os.Handler.handleCallback(Handler.java:751)
at at android.os.Handler.dispatchMessage(Handler.java:95)
at at android.os.Looper.loop(Looper.java:154)
at at android.app.ActivityThread.main(ActivityThread.java:6077)
at at java.lang.reflect.Method.invoke(Native Method)
at at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
Kindly help..