Enter following comands in a cmd window:
git clone https://github.com/SFML/SFML.git SFML
If you already downloaded SFML before you can just use the existing one.
cd SFML mkdir build && cd build mkdir armeabi-v7a && cd armeabi-v7a
cmake -DANDROID_ABI=armeabi-v7a -DCMAKE_TOOLCHAIN_FILE=../../cmake/toolchains/android.toolchain.cmake ../.. -G "MSYS Makefiles"
You can exchange
armeabi-v7a with other architectures as you like.
For this action you probably need administrator privileges. (Run cmd.exe as admin)
make && make install
You can use
make install for multiple architectures. It all uses one sfml tag in the