重新安装Android App后，应用程序会收到旧安装的通知

Question

I know this has been discussed before, but the only solution I found (canonical IDs) don't work in my scenario.

Scenario:

• User installs App and registers with his user account A
• User gets push notifications meant to be delivered to this specific user account A
• User uninstalls the app
• User reinstalls the app
• User registers with a different user account B

Now notifications are delivered for both user accounts. From my understanding, using cannonical GCM Reg IDs would only consolidate those IDs and prevent sending duplicate notifications. In this case the App gets notifications for a different user that shouldn't be delivered at all.

Is there any fix for that? Only thing I can think of would be actively deregistering when uninstalling the app, but in another thread I read, it's not possible to execute code on deinstallation.

Answer 1

From my understanding, using cannonical GCM Reg IDs would only consolidate those IDs and prevent sending duplicate notifications.

That's one way of looking at it, but on a simpler note, Canonical IDs are like saying " old ID you used is expired, delete it (if you saved it) and use me instead ".

The thing that makes this a bit odd is that, when the user uninstalls the app, the InstanceID should be invalidated. (see the docs here ).

What I think you can do to make sure that tokens are deleted, you can call deleteInstanceId() to revoke all tokens, then re-register.

But to make sure that the message is for the intended user, you can refer to what is stated in the docs (first one similar to what @Ak9637 said):

To make sure that messages go to the intended user:

• The app server can maintain a mapping between the current user and the registration token.

• The client app can then check to ensure that messages it receives match the logged in user.

Answer 2

You can simply check ,when registering in your tokens database,when u receive token of user B , just check if it is already associated with any user or not, if it is simply nullify that field and save the new token to new user. As token identifies the device not the user.

If you wish to take total autonomy and control of notifications related to your app, You should use data notifications instead of message notifications , this will avoid the OS handling the notifications instead of your app