Check out the Kraken underwater housing - it works for Android, iPhone, etc - as long as your smart phone fits within the dimensions, it works! My dive buddy uses one with his phone in place of a camera and loves it.
I used the Watershot housing for my iPhone - back when I had an iPhone 4 - and it worked great. My fear now is if I lose my phone (flood it) I lose so much more than just pictures. Otherwise, I'd probably go back to that. My phone takes some incredible pictures!