Ah, the idea of using a phone as an actual drone controller. We keep coming back to that one every year or so, dating all the way back to my first cellphone autopilot (using Windows CE!) in 2007, to the PhoneDrone product we sold for a while at 3DR (too hard to use), to the "Flone", to the more recent U Penn/Qualcomm phone-powered drone. They always fail because, to be honest, phones aren't really designed for this and it's easier to use cheap dedicated autopilots and better cameras.
Nevertheless, phones keep getting better and lord knows we've all got a few spare ones. So there is now yet another "PhoneDrone" project on Kickstarter. Not enough details to know how it really works, but it's a cool concept. check it out and decide for yourself.