android studio cmake里同时加入opencv和ncnn后报错：use of typeid requires -frtti

[ljmkimqx]

报的错误:

In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/mtcnnFace/tracking-lib.cpp:4:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/opencv.hpp:65:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann.hpp:48:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann/flann_base.hpp:40:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann/params.h:33:
/Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann/any.h:58:63: error: use of typeid requires -frtti

之前已经成功集成ncnn在项目里了，并且可以正常使用。
然后我想尝试其他模型，并且需要opencv，我就按照下面的cmake进行配置，但报了上面的错，我尝试cmake里加上这句

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -frtti")

但也报相同的错误

cmake:

project(mtcnnFace)

cmake_minimum_required(VERSION 3.4.1)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -frtti")

add_library(lib_opencv_flann SHARED IMPORTED)
set_target_properties(lib_opencv_flann PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../jniLibs/${ANDROID_ABI}/libopencv_flann.a)

add_library(lib_opencv SHARED IMPORTED)
set_target_properties(lib_opencv PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../jniLibs/${ANDROID_ABI}/libopencv_java4.so)

set(ncnn_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../ncnnFace/${ANDROID_ABI}/lib/cmake/ncnn)
find_package(ncnn REQUIRED)

include_directories(mtcnn.h LandmarkTracking.h)

add_library(mtcnnFace SHARED mtcnn.cpp tracking-lib.cpp)

#C++日志
find_library(log-lib log)

target_link_libraries(mtcnnFace
        ncnn
        lib_opencv
        lib_opencv_flann
        ${log-lib}
        android
        jnigraphics
        )

ndk: 21.3.65
android studio: 2020.3.1

请问这可能是什么问题，弄了很久

[nihui]

方案1：自行编译ncnn库，设置cmake选项 -DNCNN_DISABLE_RTTI=OFF
方案2：使用 https://github.com/nihui/opencv-mobile 替换官方的opencv

[ljmkimqx]

采用了方案1，并添加了 -DNCNN_DISABLE_RTTI=OFF（环境信息： ndk:21.4.7075529 ncnn: ncnn-20210720源码）
放到项目后rebuild,不报 error: use of typeid requires -frtti 错误了
但报了另一个错误：cannot use 'throw' with exceptions disabled

In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/mtcnnFace/tracking-lib.cpp:4:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/opencv.hpp:65:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann.hpp:48:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann/flann_base.hpp:40:
In file included from /Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann/params.h:33:
/Users/ljm/Desktop/ProjectAndroid/JXA/app/src/main/cpp/include/opencv2/flann/any.h:274:42: error: cannot use 'throw' with exceptions disabled

按照网上说的在build.gradle里添加“-fexceptions”也不行

我在APP的build.gradle里android的defaultConfig配置如下

defaultConfig {
        applicationId "加密加密加密"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 1
        versionName "1.0.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

        externalNativeBuild {
            cmake {
                arguments "DANDROID_TOOLCHAIN=clang"
                cppFlags "-std=c++11 -fexceptions"
                abiFilters "armeabi-v7a", "arm64-v8a"
            }
        }
    }

cmake文件内容和上面的一样
opencv: 4以上
ndk: 21.3.65
android studio: 2020.3.1

[nihui]

-DNCNN_DISABLE_EXCEPTION=OFF

[ljmkimqx]

可以了 谢谢nihui