Am trying to integrate google plus on existing android app . Have created google api console project at https://code.google.com/apis/console/ .Now as this link says https://developers.google.com/+/quickstart/android we need to "Create an OAuth 2.0 Client ID" ,after creating it gives an error message as "This client ID is globally unique and is already in use" .May be its saying i cant used same SHA1 key but, need to use same key for all the google API's. Thanks
Solution:
Deleted debug.keystore from android folder (users--->.android--->debug.keystore), then run the app and a new key store will be generated ,generate SHA1 from that key store and problem is solved.Thanks https://code.google.com/p/google-plus-platform/issues/detail?id=554
