这是我的解决方案。

特征

1. 适用于Android和iOS。
2. 使用静态链接而不是动态链接。（因此，代码大小要小得多。）
3. 最新版本为2020.07.28。（由于这些API的变化很快，而且许多文章都有些陈旧。）

入门

注意：如果您已经有一个应用程序，则可以跳过本节：)本节假定您根本没有任何代码。

可以从此处下载示例代码。

步骤0 ：确保您具有Flutter环境，并遵循官方的“使用Flutter编写C
++”教程
。

注意 ： 必须 遵循“在iOS上，您需要告诉Xpre静态链接文件：…”的步骤。否则，在我们的最后一步，iOS将抱怨找不到该符号。

第1步
：使用OpenCV编写所需的任何代码。例如，我更改

ios/Classes/native_add.cpp

#include <stdint.h>#include <opencv2/core.hpp>extern "C" __attribute__((visibility("default"))) __attribute__((used))int32_t native_add(int32_t x, int32_t y) {    cv::Mat m = cv::Mat::zeros(x, y, CV_8UC3);    return m.rows + m.cols;}

安卓系统

步骤0
：从官方网站下载Android OpenCV sdk
。假设我将其放在桌面上。

/Users/tom/Others/OpenCVRelease/OpenCV-android-sdk

步骤1.1 ：将更

android/CMakeLists.txt

OPENCV_base_DIR

cmake_minimum_required(VERSION 3.4.1)# TODO please change me!set(OPENCV_base_DIR "TODO PLEASE PUT YOUR DIR HERE!!!")set(OPENCV_INCLUDE_DIR "${OPENCV_base_DIR}/sdk/native/jni/include/")set(OPENCV_STATIC_LIB_DIR "${OPENCV_base_DIR}/sdk/native/staticlibs/${ANDROID_ABI}")set(OPENCV_3RDPARTY_STATIC_LIB_DIR "${OPENCV_base_DIR}/sdk/native/3rdparty/libs/${ANDROID_ABI}")include_directories(${OPENCV_INCLUDE_DIR})find_library(log-lib log)add_library(highgui STATIC importED)set_target_properties(highgui PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_highgui.a)add_library(calib3d STATIC importED)set_target_properties(calib3d PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_calib3d.a)add_library(core STATIC importED)set_target_properties(core PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_core.a)add_library(dnn STATIC importED)set_target_properties(dnn PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_dnn.a)add_library(flann STATIC importED)set_target_properties(flann PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_flann.a)add_library(imgproc STATIC importED)set_target_properties(imgproc PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_imgproc.a)add_library(videoio STATIC importED)set_target_properties(videoio PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_videoio.a)add_library(imgprecs STATIC importED)set_target_properties(imgprecs PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_imgprecs.a)add_library(features2d STATIC importED)set_target_properties(features2d PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_features2d.a)add_library(ml STATIC importED)set_target_properties(ml PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_ml.a)add_library(photo STATIC importED)set_target_properties(photo PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_photo.a)add_library(shape STATIC importED)set_target_properties(shape PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_shape.a)add_library(objdetect STATIC importED)set_target_properties(objdetect PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_objdetect.a)add_library(stitching STATIC importED)set_target_properties(stitching PROPERTIES importED_LOCATION ${OPENCV_STATIC_LIB_DIR}/libopencv_stitching.a)include(AndroidNdkModules)android_ndk_import_module_cpufeatures()set(CMAKE_THREAD_PREFER_PTHREAD TRUE)set(THREADS_PREFER_PTHREAD_FLAG TRUE)find_package(Threads REQUIRED)add_library(tbb STATIC importED)set_target_properties(tbb PROPERTIES importED_LOCATION ${OPENCV_3RDPARTY_STATIC_LIB_DIR}/libtbb.a)add_library(tegra_hal STATIC importED)set_target_properties(tegra_hal PROPERTIES importED_LOCATION ${OPENCV_3RDPARTY_STATIC_LIB_DIR}/libtegra_hal.a)add_library(ittnotify STATIC importED)set_target_properties(ittnotify PROPERTIES importED_LOCATION ${OPENCV_3RDPARTY_STATIC_LIB_DIR}/libittnotify.a)add_library(native_with_opencv        # Sets the library as a shared library.        SHARED        # Provides a relative path to your source file(s).        ../ios/Classes/native_add.cpp        )target_link_libraries(native_with_opencv        ${log-lib}        core        # note: You can import whatever other modules you like (e.g. dnn)        tbb # note: need to be placed *after* "core"        cpufeatures        ittnotify        tegra_hal # NOTE if still have error, check abiFilters, since tegra does *not* exist in x86.        Threads::Threads        -lz        )

当然，

lib/native_with_opencv.dart

.so

"libnative_with_opencv.so"

步骤1.2 ：更改

android/build.gradle

android {    ...    defaultConfig {        ...        // [[[CHANGE 1: Make minSdkVersion bigger]]]        // see https://github.com/opencv/opencv/issues/14419        minSdkVersion 21        // [[[CHANGE 2: Add these flags and filters]]]        externalNativeBuild { cmake {     cppFlags "-frtti -fexceptions -std=c++11"     abiFilters 'armeabi-v7a', 'arm64-v8a' }        }        ...    }    ...}

当然，

minSdkVersion

native_with_opencv/example/android/app/build.gradle

完成！编译并享受它（并转到iOS的下一部分）！如果看到

1 + 2 == 3

奖励：如果您在发布模式下构建并查看apk大小，您将看到我们的

.so

的iOS

步骤0 ：在中

ios/native_with_opencv.podspec

  s.static_framework = true  s.dependency 'OpenCV', '~> 4.1'

步骤1 ：编译并享受。 注意： 您可能需要先运行

podinstall

native_with_opencv/example/ios

（可选）Android配置如何工作的说明：（1）最初，我只是链接

core

error:undefined reference to'carotene_o4t::...'

libtegra_hal

tbb

core

abiFilters

tegra_hal

x86

.a

minSdkVersion

fegetenv