How to sync data in Android app whenever I make changes in Google sheet?

Question

Goal: I have a recyclerview and that recyclerview data should come either from Google Sheet or Google Contacts API or Outlook Contacts API whoever has the latest changes. In short my app should sync with this 3 places all the time.

I want enhancement on this: https://www.youtube.com/watch?v=40pqM2W7vhk&ab_channel=CrazyCodersClub

When I open contacts.csv file in Google Sheet and whenever I do CRUD operation inside Google sheet / Google Contacts / Microsoft Contacts / Android app. It should update everywhere all 4 places.

Description: So basically I want to make a contact app, which should sync Microsoft and Google contacts, and that contact app will read the data from contacts.csv file programmatically all the time, something like that.

Now I have a confusion also that which way is better?

1. Google sheet will update Google and Microsoft contacts, and I simply need to read Microsoft Excel sheet.
2. First I need to read Google Excel Sheet, and then need to do CRUD operation with Google and Microsoft contacts API.

Note: In my Android app, only user can able to see the list of contacts. No Create/Delete/Update are supports as of now. If user want to make the changes, then he can make changes from either Google contact website, Microsoft contact website or through Google sheet.

I know some requirements, other you can suggest:

1. Android app integration with Google Contacts API (2-way sync)
2. Android app integration with Outlook Contacts API (2-way sync)
3. CRUD operation with Google sheet (2-way sync)

I need a suggestion, no need to write code.

Answer 1

I would try the following:

1. Create an Android application using Azure AD/identity workflow
2. Use Microsoft Graph API's to get the contacts from Office 365/Outlook. Consider using at delta queries in Graph APIs incase if you want to track the changes
3. Use oAuth/SAML/OpenID Connect to get the contacts from Google
4. Implement your business logic to sync the data