OpenCV - undefined reference to 'cv::CascadeClassifier::detectMultiScale() after NDK update

Question

Yesterday I updated my Android Studio included NDK to version 17.0.4754217and since then I can\'t run my app anymore. When I tried to rerun the code after the u

Answer 1

OpenCV is built with ANDROID_STL=gnustl_static. After upgrade, your NDK uses the default libc++ instead. You can set ANDROID_STL explicitly in your app/build.gradle:

android { defaultConfig { externalNativeBuild { cmake {
    arguments '-DANDROID_STL=gnustl_static'
} } } }

(see an example here).