Android Studio with Scala plugin is required if you wish to compile it yourself.
Link to APK file: https://github.com/btcontract/bitcoins/blob/master/app/app-release.apk

Visual Bitcoin Wallet on popular app stores
Meizu: http://app.flyme.cn/apps/public/detail?package_name=com.btcontract.wallet
Google: https://play.google.com/store/apps/details?id=com.btcontract.wallet
Xiaomi: http://app.mi.com/detail/105943