As you see, this is only a ticker for now. This was a very early alpha we sent out, it is still missing a lot of finetuning und functionality. It will go from there to a fullblown notifcation-switcher. At this point let us express our absolute gratitude to Facebook for this idea! We loved it from the start. You people truly changed the Android landscape. And as always, all it really takes is a nice and simple idea. We hope you are not mad at us for extending it, but we liked it so much, one single app didn't cut it, this just had to work with everything...
Our solution is written from scratch, this is not cornerstone. We believe Google should have no intention in vetoing it since it should in theory pass their compatibility test suite, plus apps can opt in for all we care.
We mind Androids inner rules and activity-management. Displaying a window as an overlay from a programming perspective is done with a regular intent flag. The flag that we added creates a different set of rules in Androids life-cycle management to ensure this doesn't mess up apps. We start out with a basic version that will pause underlying apps (meaning we don't touch anything, this is Androids default) and maybe go from there to something that intercepts the pause call on high powered phones to let apps running - although this may not even be necessary.