How to access localhost from Android emulator and iOS simulator?

Evgeny Zborovsky · March 3, 2018

Being lucky to develop a backend and a Xamarin.Forms clients on your own? Sooner or later you will have to debug the API calls and it might become painful. Unless, you will follow the next rules:

  1. Configure your API URL to run on 127.0.0.1 instead of a localhost:

    // .NET Core Web.Api example public static IWebHost BuildWebHost(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup() .UseUrls(“http://127.0.0.1:5001“) .Build();

  2. Configure your Xamarin.Forms API consumer to have a conditional URL base:

    string apiUrl = null; if (Device.RuntimePlatform == Device.Android) apiUrl = “http://10.0.2.2:5001/api“; else if (Device.RuntimePlatform == Device.iOS) apiUrl = “http://localhost:5001/api“; else throw new UnsupportedPlatformException();

The problem with Android emulator is that it maps 10.0.2.2 to 127.0.0.1, not to localhost. However, the iOS Simulator uses the host machine network.

That should be it! Happy debugging!

Twitter, Facebook