First, download the Android-x86 iso. This is a patched version of the open source project Android, so that it will run on an x86-platform. Then run the following commands:
qemu-img create -f qcow2 ./android-internal-storage.qcow2 32G qemu-system-x86_64 -cdrom ~/Downloads/android-x86_64.*.iso -vga vmware -cpu host -enable-kvm -m 4G -smp 4 -drive file=./android-internal-storage.qcow2,format=qcow2
For details on these commands, check out this article: Virtual machine on linux: qemu.
There is no need to install a virtual machine manager, but if you wish to have a GUI to start/stop virtual machines, and configure settings with dialog windows, keep reading.
Installing a Virtual Machine manager: virt-manager
This allows you to make snapshots, and provide a more advanced GUI for linking devices or mounting filesystems. For details, check out this article: Virtual machine manager on linux (for qemu): virt-manager.