You can easily build a Fortran compiler for Android, the NDK source code is available and it contains gfortran. The official binary NDK however has only gcc and g++ build.
BLAS and Lapack can be compiled natively for Android with gfortran.
Which BLAS though? The reference BLAS implementation? That will have terrible performance. Would be interested to see if something better like ATLAS or OpenBLAS can be compiled for it. Recent versions of ATLAS do work on ARM Linux, so wondering if those can be easily ported to Android.
BLAS and Lapack can be compiled natively for Android with gfortran.