如何知道电话中的哪些联系人使用我们的应用程序

Question

I am working on a chat app with kotlin language and I am trying to load all the contacts which are presently on the users phone.

I am saving their phone numbers in my database but I also want the users to know that which contacts are using this app and which are not using.

I have been watching tutorials to do this but am not able to find it. Please if anybody can help. It would be great.

Answer 1

I don't think there is anyway apart from searching through your database. For contact in your users phone check if the number is in your database. You could sort the numbers in your database so that you can use binary search and make it faster.