I have multiple api which we have provided to android developers.
Like :
1) Creating  Business card API
2) Creating Contacts API
So these api working fine when app is online. So our requirement is to handle to create business card and contacts when app is offline.
We are following steps but not sure:-
1) Android developer store the business card when app offline and send this data to server using separate offline business card api when app comes online.
2) Same we do for creating contacts offline using offline contact api.
My problem is I want do in one api call to send all data to server and do operation.
Is this approach will right?? Also please suggest what is the best approach to handle offline data. Also how to handle syncing data when app would come online??
Please let me know if I could provide more information.
I'm confused as to how you're approaching this.  My understanding is that when the app is offline you want to "queue up" any API requests that are sent.
Your process seems fine however without knowing the terms around the app being "offline" it's hard to understand if this best.
Assuming you're meaning the server(s) holding the application are offline you're correct you want a process in the android app that will store the request until the application becomes online.  However, this can be dangerous for end users.  They should be receiving a message on the application being offline and to "try again later" as it were.  The fear being they submit a request for x new contacts to be queued and then re-submit not realizing the application was offline.
I would suggest you have the android app built to either notify the user of the app being down or provide some very visible notification that requests are queued locally on their phone until the application becomes available and for them to view/modify/delete said locally cached requests until the application becomes available.  When the API becomes available a notification can be set for users to release their queue on their device.
how to design rest api which handle offline data