Execution failed for task ':simple_edge_detection:externalNativeBuildDebug' - flutter

Question

i am using simple_edge_detection library from here :
https://www.flutterclutter.dev/flutter/tutorials/implementing-edge-detection-in-flutter/2020/1509/
CMakeLists.txt
cmake_minimum_required(VERSION 3.4.1)
include_directories(../include)
add_library(lib_opencv SHARED IMPORTED)
set_target_properties(lib_opencv PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libopencv_java4.so)
set(EDGE_DETECTION_DIR "../ios/Classes")
set(SOURCES
${EDGE_DETECTION_DIR}/native_edge_detection.cpp
${EDGE_DETECTION_DIR}/edge_detector.cpp
${EDGE_DETECTION_DIR}/image_processor.cpp
)
add_library(native_edge_detection SHARED ${SOURCES})
target_link_libraries(native_edge_detection lib_opencv)
build.gradle:
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
android {
compileSdkVersion 28
// flavorDimensions "default"
sourceSets {
main.java.srcDirs += 'src/main/kotlin'
}
lintOptions {
disable 'InvalidPackage'
}
defaultConfig {
// TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
applicationId "dev.flutterclutter.simple_edge_detection_example"
minSdkVersion 21
targetSdkVersion 28
versionCode flutterVersionCode.toInteger()
versionName flutterVersionName
externalNativeBuild {
cmake {
cppFlags '-frtti -fexceptions -std=c++11'
arguments "-DANDROID_STL=c++_shared"
}
}
}
buildTypes {
release {
// TODO: Add your own signing config for the release build.
// Signing with the debug keys for now, so `flutter run --release` works.
signingConfig signingConfigs.debug
}
}
externalNativeBuild {
cmake {
path "D:/Flutter Projects/flutter-simple-edge-detection/example/android/CMakeLists.txt"
}
}
}
but m getting this error :
FAILURE: Build failed with an exception.
Execution failed for task ':simple_edge_detection:externalNativeBuildDebug'.
Build command failed.
Error while executing process C:\Users\Andorid\AppData\Local\Android\Sdk\cmake\3.6.4111459\bin\cmake.exe with arguments {--build D:\Flutter Projects\flutter-simple-edge-detection\android.cxx\cmake\debug\armeabi-v7a --target native_edge_detection}
ninja: error: '../../../../src/main/jniLibs/armeabi-v7a/libopencv_java4.so', needed by 'D:/Flutter Projects/flutter-simple-edge-detection/example/build/simple_edge_detection/intermediates/cmake/debug/obj/armeabi-v7a/libnative_edge_detection.so', missing and no known rule to make it