Android Keyboard is not getting hide when click the Home Button of the Device?

I am showing Pin Screen when ever the application goes to background. I am using Xamarin stable Form 1.3 Version. I handle the Pin Page through App OnSleeep() and OnResume() method. Problem is like when keyboard appear in any page, then app goes to background so before showing Pin Page , need to hide the Keyboard explicitly. When using screen lock button its work fine except the Home Button.

Any suggestion will be highly appreciated.