RaspAnd is a Linux distribution which makes it possible to run Android 5.1 Lollipop on a Raspberry Pi 2.
The Raspberry Pi is a very popular low cost, credit-card sized computer & several Linux distributions are released for this device. Swedish developer Exton created the RaspAnd Linux distribution to make it possible to run Android 5.1 Lollipop on the latest Raspberry Pi; version 2 (Model B) & is using Kernel 3.19.0-exton-v7+.
The installation is quite straightforward & has to take place in Linux (from hard drive, or while running a live Linux system from cd or a USB stick). Four partitions needs to be created on a Micro SD Card with Fdisk, or Gparted. The partitions needs to initialized afterwards and 8 files needs to be copied to raspex-android-x86-lollipop-5.1/boot.
Head over here to read the complete instructions & to download RaspAnd ($9 USD)