p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left }
p.western { font-family: "Liberation Serif", serif; font-size: 12pt }
p.cjk { font-family: "Source Han Sans CN Regular"; font-size: 12pt }
p.ctl { font-family: "Lohit Devanagari"; font-size: 12pt }
a:link { }
本文以编译opencv 3.3.0 和 opencv_contrib 3.3.0为例，系统为 Linux x64 (Fedora 21)，具体步骤如下：
1. 下载 Source code zip 压缩包
从下面网址，选择 opencv 3.3.0 Source code 下载
https://github.com/opencv/opencv/releases
从下面网址，选择下载与
opencv
3.3.0 对应的
opencv_contrib
3.3.0
https://github.com/opencv/opencv_contrib/releases
注意：opencv和opencv_contrib
版本必须保持一致，否则可能会出现编译错误。
2.
下载
build-opencv-for-android
开源代码
$ cd /mnt/work $ git clone https://github.com/tzutalin/build-opencv-for-android.git $ cd build-opencv-for-android
3. 解压源码包并重命名
将opencv-3.3.0.zip 和 opencv_contrib-3.3.0.zip 都解压到下载的build-opencv-for-android 开源代码 所在目录 /mnt/work/build-opencv-for-android 。
$ unzip opencv-3.3.0.zip -d /mnt/work/build-opencv-for-android $ unzip opencv_contrib-3.3.0.zip -d /mnt/work/build-opencv-for-android $ cd /mnt/work/build-opencv-for-android $ mv opencv-3.3.0 opencv $ mv opencv_contrib-3.3.0 opencv_contrib
4. 修改 build-opencv-for-android 开源代码中 build-android-opencv.sh
修改内容如下：
修改 第 6 行代码：
declare -a ANDROID_ABI_LIST=("x86" "x86_64" "armeabi" "arm64-v8a" "armeabi-v7a" "mips" "mips64")
为
declare -a ANDROID_ABI_LIST=("armeabi-v7a")
最终代码，如下：
1 #!/bin/bash
2 NDK_ROOT="${1:-${NDK_ROOT}}"
3
4 ### ABIs setup
5 #declare -a ANDROID_ABI_LIST=("x86" "x86_64" "armeabi-v7a with NEON" "arm64-v8a")
6 declare -a ANDROID_ABI_LIST=("armeabi-v7a")
7
8 ### path setup
9 SCRIPT=$(readlink -f $0)
10 WD=`dirname $SCRIPT`
11 OPENCV_ROOT="${WD}/opencv"
12 N_JOBS=${N_JOBS:-4}
13
14 ### Download android-cmake
15 if [ ! -d "${WD}/android-cmake" ]; then
16 echo ‘Cloning android-cmake‘
17 git clone https://github.com/taka-no-me/android-cmake.git
18 fi
19
20 INSTALL_DIR="${WD}/android_opencv"
21 rm -rf "${INSTALL_DIR}/opencv"
22
23 ### Make each ABI target iteratly and sequentially
24 for i in "${ANDROID_ABI_LIST[@]}"
25 do
26 ANDROID_ABI="${i}"
27 echo "Start building ${ANDROID_ABI} version"
28
29 if [ "${ANDROID_ABI}" = "armeabi" ]; then
30 API_LEVEL=19
31 else
32 API_LEVEL=21
33 fi
34
35 temp_build_dir="${OPENCV_ROOT}/platforms/build_android_${ANDROID_ABI}"
36 ### Remove the build folder first, and create it
37 rm -rf "${temp_build_dir}"
38 mkdir -p "${temp_build_dir}"
39 cd "${temp_build_dir}"
40
41 cmake -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON 42 -DCMAKE_TOOLCHAIN_FILE="${WD}/android-cmake/android.toolchain.cmake" 43 -DANDROID_NDK="${NDK_ROOT}" 44 -DANDROID_NATIVE_API_LEVEL=${API_LEVEL} 45 -DANDROID_ABI="${ANDROID_ABI}" 46 -D WITH_CUDA=OFF 47 -D WITH_MATLAB=OFF 48 -D BUILD_ANDROID_EXAMPLES=OFF 49 -D BUILD_DOCS=OFF 50 -D BUILD_PERF_TESTS=OFF 51 -D BUILD_TESTS=OFF 52 -DOPENCV_EXTRA_MODULES_PATH="${WD}/opencv_contrib/modules/" 53 -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}/opencv" 54 ../..
55 # Build it
56 make -j${N_JOBS}
57 # Install it
58 make install/strip
59 ### Remove temp build folder
60 cd "${WD}"
61 rm -rf "${temp_build_dir}"
62 echo "end building ${ANDROID_ABI} version"
63 done
说明：
1). 由于目前 大多数 android 平台使用arm cpu, 采用armeabi-v7 指令集，为了减少编译时间，所有我只保留 "armeabi-v7a" ， 其他删除，如果需要也可保留。
2). armeabi-v7 代表 arm EABI version 7 指令集, EABI 为 嵌入应用二进制接口 (Embedded Application Binary Interface) 。
5. 执行脚本 build-android-opencv.sh
$ ./build-android-opencv.sh /mnt/work/android/android-sdk-linux/ndk-bundle
注：build-android-opencv.sh脚本的通用的执行命令格式为“./build-android-opencv.sh [NDK_ROOT]”，其中，参数NDK_ROOT是可选的，表示Android Native Development Kit (NDK) 顶层目录，如果没有提供，则会试图寻找环境变量 ANDROID_NDK。
6. 查看编译结果
编译成功后，会在 build-opencv-for-android 目录，即build-android-opencv.sh脚本所在目录，生成 android_opencv目录，其目录结构如下：
$ tree -d android_opencv android_opencv └── opencv ├── apk └── sdk ├── etc │ ├── haarcascades │ └── lbpcascades └── native ├── 3rdparty │ └── libs │ └── armeabi-v7a ├── jni │ ├── abi-armeabi-v7a │ └── include │ ├── opencv │ └── opencv2 │ ├── aruco │ ├── bioinspired │ ├── calib3d │ ├── ccalib │ ├── core │ │ ├── cuda │ │ │ └── detail │ │ ├── hal │ │ └── utils │ ├── datasets │ ├── dnn │ ├── face │ ├── features2d │ ├── flann │ ├── fuzzy │ ├── highgui │ ├── imgcodecs │ ├── img_hash │ ├── imgproc │ │ ├── detail │ │ └── hal │ ├── line_descriptor │ ├── ml │ ├── objdetect │ ├── optflow │ ├── phase_unwrapping │ ├── photo │ ├── reg │ ├── rgbd │ ├── saliency │ ├── shape │ ├── stereo │ ├── stitching │ │ └── detail │ ├── structured_light │ ├── superres │ ├── surface_matching │ ├── text │ ├── tracking │ ├── video │ ├── videoio │ ├── videostab │ ├── xfeatures2d │ ├── ximgproc │ └── xphoto └── libs └── armeabi-v7a 62 directories
问题与解决方法
问题一
$ ./build-android-opencv.sh
Start building armeabi-v7a version
CMake Error at /mnt/work/video/res/opencv/build-opencv-for-android-master/android-cmake/android.toolchain.cmake:446 (message):
Could not find neither Android NDK nor Android standalone toolchain.
You should either set an environment variable:
export ANDROID_NDK=~/my-android-ndk
or
export ANDROID_STANDALONE_TOOLCHAIN=~/my-android-toolchain
or put the toolchain or NDK in the default path:
sudo ln -s ~/my-android-ndk /opt/android-ndk
sudo ln -s ~/my-android-toolchain /opt/android-toolchain
Call Stack (most recent call first):
/usr/share/cmake/Modules/CMakeDetermineSystem.cmake:98 (include)
CMakeLists.txt:127 (project)
CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.
Missing variable is:
CMAKE_CXX_COMPILER_ENV_VAR
CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.
Missing variable is:
CMAKE_CXX_COMPILER
CMake Error: Could not find cmake module file: /mnt/work/video/res/opencv/build-opencv-for-android-master/opencv/platforms/build_android_armeabi-v7a/CMakeFiles/3.0.2/CMakeCXXCompiler.cmake
CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.
Missing variable is:
CMAKE_C_COMPILER_ENV_VAR
CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.
Missing variable is:
CMAKE_C_COMPILER
CMake Error: Could not find cmake module file: /mnt/work/video/res/opencv/build-opencv-for-android-master/opencv/platforms/build_android_armeabi-v7a/CMakeFiles/3.0.2/CMakeCCompiler.cmake
CMake Error at CMakeLists.txt:127 (project):
No CMAKE_CXX_COMPILER could be found.
Tell CMake where to find the compiler by setting the CMake cache entry
CMAKE_CXX_COMPILER to the full path to the compiler, or to the compiler
name if it is in the PATH.
CMake Error at CMakeLists.txt:127 (project):
No CMAKE_C_COMPILER could be found.
Tell CMake where to find the compiler by setting the CMake cache entry
CMAKE_C_COMPILER to the full path to the compiler, or to the compiler name
if it is in the PATH.
CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage
CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
-- Configuring incomplete, errors occurred!
make: *** No targets specified and no makefile found. Stop.
make: *** No rule to make target ‘install/strip‘. Stop.
end building armeabi-v7a version
解决方法
方法一（推荐方法）
p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left }
p.western { font-family: "Liberation Serif", serif; font-size: 12pt }
p.cjk { font-family: "Source Han Sans CN Regular"; font-size: 12pt }
p.ctl { font-family: "Lohit Devanagari"; font-size: 12pt }
a:link { }
从命令行传入 NDK_ROOT 目录，如下：
$ ./build-android-opencv.sh /mnt/work/android/android-sdk-linux/ndk-bundle/
方法二，
根据提示，设置环境变量 ANDROID_NDK，如下
p { margin-bottom: 0.1in; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left }
p.western { font-family: "Liberation Serif", serif; font-size: 12pt }
p.cjk { font-family: "Source Han Sans CN Regular"; font-size: 12pt }
p.ctl { font-family: "Lohit Devanagari"; font-size: 12pt }
a:link { }
$ export ANDROID_NDK=/mnt/work/android/android-sdk-linux/ndk-bundle/ $ env | grep ANDROID_NDK ANDROID_NDK=/mnt/work/android/android-sdk-linux/ndk-bundle/ $ ./build-android-opencv.sh
参考资料
1. Build and install OpenCV and contrib lib on Ubuntu / Android 链接一 链接二（转载）
2. 如何编译 opencv3 和 opencv_contrib（Linux）