This post is a bit of an aide-mémoire for myself. If you ever need to see which key signed an APK (for example to compare to a client ID in the API console when implementing Google+ Sign-In) you can actually extract the cert from the APK, and test it.

It has been fantastic to see so many people trying out Google+ Sign-In, and through the bootcamps and other events I’ve had a chance to talk to some people who are actually implementing it in their apps. The Android integration is pretty straightforward, thanks to Google Play Services, but there are still some issues I’ve seem come up a couple of times.

As part of the release of Google+ Sign-In, some people have noticed that signing in via the Sign In button doesn’t redirect them to Google, then back to the site, as would have happened if they’d been using the basic OAuth 2.0 flows.

This is as much an aide-mémoire for myself as anything else, but in case you’re using the Objective-C Google API client, you may at some point need to use the simple API access method. This is where you pass an API key to identify the call as being under a certain project, rater than using a full OAuth2 authentication flow. This doesn’t allow access to personal data, but does mean that any calls will be tracked under the quota for your project, rather than a (lower) IP based quota.

One pretty common request around Google+ hangouts is the ability to programmatically schedule them, and have a URL which everyone can join in the future. This is useful for being able to send out links beforehand, and make sure people are ready to go.