Setup a server which will receive the tokens from the users using your app.
When a user start you app and get a token you send this token together with other informations (to know which user is this token).
Store it on your server.
After that you can send a request to the server to give you the token from user x. Or device y....
Depends on you requirement
Setup a server which will receive the tokens from the users using your app.
When a user start you app and get a token you send this token together with other informations (to know which user is this token).
Store it on your server.
After that you can send a request to the server to give you the token from user x. Or device y....
Depends on you requirement
Thank you DonManfred , I know this way but I think it doesn't correct way because it's not real time channel and I have to after a few seconds send a request to server to know who is online