Android studio app with .net REST service

Dear All,

here i am attaching a project developed in android studio using .net WCF REST service in the below link.

i have an issue with java class HomeFragment.java inside this page i am using function refreshVehicles() to call the REST service.

please any of you review the code and fix the issue or am i missing anything here. please advice.

last one week i am struggling with this. complete source code attached here.

Thanks

Abdul Manzoor