问题
I've read in Google Cloud Messaging documentation that GCM key is unique per device and per application. If I uninstall and reinstall the application the key is always the same, ie, the key is calculated based on some device and application identifiers or the key will change?
回答1:
No, the key (called Registration ID) may change after you uninstall and re-install the app.
The following scenario will cause the ID to change :
- un-install the app
- send a GCM message to the device several times, until GCM server realizes that the app was uninstalled from the device
- re-install the app
来源：https://stackoverflow.com/questions/17594948/google-cloud-messaging-unique-key