How to give exit app button in xamarin forms

to close xamarin form application from button tap

first you need to create one dependency service inside your portable project as follows

 

right click on portable project and add interface and give name as  ExitAppInterface then you can see one class open in your VS, then replace that interface part with below code

 then in your android project open your main MainActivity.cs class then inside class add below code

 

 now you in your button tap you can call this exit app function through dependency service as below

  note:here my button tap event is exitTap, so based on what ever your event name, inside that just write

 

  DependencyService.Get().exitApp();