Linking errors on Android with OpenCV 3.4.0 and NDK

Question

I am trying to port existing computer vision code, written in C++ using OpenCV, to Android NDK. I successfully imported the OpenCV library version 3.4.0 (using the official

Answer 1

Recently, NDK switched to libc++ as default STL, but OpenCV is built with gnustl.

externalNativeBuild {
  cmake {
    arguments "-DANDROID_STL=gnustl_shared"
  }
}

for your library will fix that.

Alternatively, you can rebuild OpenCV with c++_shared.

Update: Good news! You can simply download OpenCV 4.0.1 and it will work smoothly with NDK r.18+.