How can I instert data to my ContentProvider from Rest API once?

[Ahmet Bugra Ozcan]

I want to make a caller id app which detects incoming call, searches database, if user exist and shows user in screen with dialog or by changing phone lookup. So I found 2 ways to do that. First, I created a BroadcastReceiver with incoming call intent and I showed a dialog when there is an incoming call. It worked good but sometimes my onreceive method didnt run (I tried everything to solve that but didnt solve it). So I tried to find new ways to do that and I find Content Provider. . In ContentProvider, I want to insert data from my Rest API to my Content Provider. Is it possible? When I search it I found sync adapters but I don't know what is it and I don't know can I do what I want with that. I am beginner in Android and I don't know where should I do that process. I would be glad if you could guide me.

I started from this example and I want to add on it.(https://medium.com/@jmichaelis/android-your-users-as-caller-id-d446a58d9305)