[Q] How to detect loading screens with uiautomator or any other android services?

I have been working with the UIAutomator and trying to detect when an app finishes loading (e.g. Wait for search results to return on a "search screen"). I have tried using waitForIdle in the UIAutomator TestCases API with no luck. Is there any other ways to detect when the app is trying to load things from a Web service or local source etc.

Is there a general solution to this (not limited to detecting database query/ Web query)? Is there any ways/events to find out the UI is still awaiting a background task to be finished and getting updated? Is there any other Android Services that i can make use of regarding this issue other than the uiautomator?

Thanks!

(P.S. I have engineering build on my phone and all permissions available)