title: how to grab referrer/campaign source from google analytics
body: <p>from the very bottom of <a href="https://developers.google.com/analytics/devguides/collection/android/v2/campaigns" rel="nofollow noreferrer">here</a>. theres a URL generator which I can generate a link to my app on google play with a referrer. How can I extra that campaign source from google analytics?? I've been searching on google but still can't find the answer. i found someone saying that I should make a class which extends BroadcastReceiver, but I also found <a href="https://stackoverflow.com/questions/3817030/get-android-google-analytics-referrer-tag">here</a>. by doing that, I won't be able to get GA work. GA is very powerful and I want to use it. All I need now is to extract a parameter which is the referrer/campaign source from GA. I also found that there are several getters under EasyTracker.getTracker(), like getAppId(), getAppInstallerId() and getTrackingId(), but none of them is documented. how do I know which ID getter belongs to which? 
  Thanks for the help! </p>