The Android.ActivityUtils package aims to help with interacting with the root Android Activity from Uno.

It currently provides:

  • a way to get the root Activity as a Java.Object
  • a way to launch an Activity optionally providing a Uno callback and some associated Uno data.

Using the library

Simply include Android.ActivityUtils in the Packages list in your unoproj file. Something like:

    "Packages": [
    "Includes": [

Retrieving the root Activity

Simply call ActivityUtils.GetRootActivity(). This will return the root Activity object as a Java.Object.

Naturally this will not work on non-android builds where it will instead return null.

Starting an Activity

This is achieved with the StartActivity method. This method has 3 overloads:

  • StartActivity(Java.Object _intent)
  • StartActivity(Java.Object intent, ActivityResultCallback callback)
  • StartActivity(Java.Object intent, ActivityResultCallback callback, object info)

The first simply calls android's startActivity method on the intent.

The second calls startActivityForResult but will call your callback when the result from the Activity is ready.

The third does the same as the second but let's you pass any uno object to StartActivity. This object is not sent, but is instead passed to your callback along with the result when the result is ready.

ActivityResultCallback is a delegate defined as delegate void ActivityResultCallback(int resultCode, Java.Object intent, object info)

Here is an example of a valid callback method in Uno

extern(android) void OnResult(int resultCode, Java.Object intent, object info)
    debug_log "\nblam!: "+resultCode+" - "+intent + "\n";

If you used the second overload of StartActivity (the one without the info object) then info in the callback will be null.