One of my favorite iOS features is that, when you have a call or turn-by-turn navigation in progress and switch apps, you can easily return just by tapping the status bar.
In android, I've noticed a number of apps that can show floating widgets over other apps - Facebook messenger's floating "chat heads" and CyanogenMod's floating calculator widget are good examples.
Is there any way to make similar floating icons appear when on a call or when navigating in the background, that when tapped will quickly return to the relevant app?