android - 在 Android NDK 中编译 OpenCV

Question

请查看底部的添加内容!第一个问题在 Linux 下解决了，在 Windows 和 Cygwin 下还没有解决，但是有一个新的问题。请看下面!

我目前正在尝试为 Android NDK 编译 OpenCV，以便我可以在我的应用程序中使用它。为此，我尝试遵循本指南:

http://www.stanford.edu/~zxwang/android_opencv.html

但是当用 ndk-build 编译下载的东西时，我得到这个错误:

$ /cygdrive/u/flori/workspace/android-ndk-r5b/ndk-build
Compile++ thumb  : opencv <= cvjni.cpp
Compile++ thumb  : cxcore <= cxalloc.cpp
Compile++ thumb  : cxcore <= cxarithm.cpp
Compile++ thumb  : cxcore <= cxarray.cpp
Compile++ thumb  : cxcore <= cxcmp.cpp
Compile++ thumb  : cxcore <= cxconvert.cpp
Compile++ thumb  : cxcore <= cxcopy.cpp
Compile++ thumb  : cxcore <= cxdatastructs.cpp
Compile++ thumb  : cxcore <= cxdrawing.cpp
Compile++ thumb  : cxcore <= cxdxt.cpp
Compile++ thumb  : cxcore <= cxerror.cpp
Compile++ thumb  : cxcore <= cximage.cpp
Compile++ thumb  : cxcore <= cxjacobieigens.cpp
Compile++ thumb  : cxcore <= cxlogic.cpp
Compile++ thumb  : cxcore <= cxlut.cpp
Compile++ thumb  : cxcore <= cxmathfuncs.cpp
Compile++ thumb  : cxcore <= cxmatmul.cpp
Compile++ thumb  : cxcore <= cxmatrix.cpp
Compile++ thumb  : cxcore <= cxmean.cpp
Compile++ thumb  : cxcore <= cxmeansdv.cpp
Compile++ thumb  : cxcore <= cxminmaxloc.cpp
Compile++ thumb  : cxcore <= cxnorm.cpp
Compile++ thumb  : cxcore <= cxouttext.cpp
Compile++ thumb  : cxcore <= cxpersistence.cpp
Compile++ thumb  : cxcore <= cxprecomp.cpp
Compile++ thumb  : cxcore <= cxrand.cpp
Compile++ thumb  : cxcore <= cxsumpixels.cpp
Compile++ thumb  : cxcore <= cxsvd.cpp
Compile++ thumb  : cxcore <= cxswitcher.cpp
Compile++ thumb  : cxcore <= cxtables.cpp
Compile++ thumb  : cxcore <= cxutils.cpp
StaticLibrary  : libstdc++.a
StaticLibrary  : libcxcore.a
Compile++ thumb  : cv <= cvaccum.cpp
Compile++ thumb  : cv <= cvadapthresh.cpp
Compile++ thumb  : cv <= cvapprox.cpp
Compile++ thumb  : cv <= cvcalccontrasthistogram.cpp
Compile++ thumb  : cv <= cvcalcimagehomography.cpp
Compile++ thumb  : cv <= cvcalibinit.cpp
Compile++ thumb  : cv <= cvcalibration.cpp
Compile++ thumb  : cv <= cvcamshift.cpp
Compile++ thumb  : cv <= cvcanny.cpp
Compile++ thumb  : cv <= cvcolor.cpp
Compile++ thumb  : cv <= cvcondens.cpp
Compile++ thumb  : cv <= cvcontours.cpp
Compile++ thumb  : cv <= cvcontourtree.cpp
Compile++ thumb  : cv <= cvconvhull.cpp
Compile++ thumb  : cv <= cvcorner.cpp
Compile++ thumb  : cv <= cvcornersubpix.cpp
Compile++ thumb  : cv <= cvderiv.cpp
Compile++ thumb  : cv <= cvdistransform.cpp
Compile++ thumb  : cv <= cvdominants.cpp
Compile++ thumb  : cv <= cvemd.cpp
Compile++ thumb  : cv <= cvfeatureselect.cpp
Compile++ thumb  : cv <= cvfilter.cpp
Compile++ thumb  : cv <= cvfloodfill.cpp
Compile++ thumb  : cv <= cvfundam.cpp
Compile++ thumb  : cv <= cvgeometry.cpp
Compile++ thumb  : cv <= cvhaar.cpp
Compile++ thumb  : cv <= cvhistogram.cpp
Compile++ thumb  : cv <= cvhough.cpp
Compile++ thumb  : cv <= cvimgwarp.cpp
Compile++ thumb  : cv <= cvinpaint.cpp
Compile++ thumb  : cv <= cvkalman.cpp
Compile++ thumb  : cv <= cvlinefit.cpp
Compile++ thumb  : cv <= cvlkpyramid.cpp
Compile++ thumb  : cv <= cvmatchcontours.cpp
Compile++ thumb  : cv <= cvmoments.cpp
Compile++ thumb  : cv <= cvmorph.cpp
Compile++ thumb  : cv <= cvmotempl.cpp
Compile++ thumb  : cv <= cvoptflowbm.cpp
Compile++ thumb  : cv <= cvoptflowhs.cpp
Compile++ thumb  : cv <= cvoptflowlk.cpp
Compile++ thumb  : cv <= cvpgh.cpp
Compile++ thumb  : cv <= cvposit.cpp
Compile++ thumb  : cv <= cvprecomp.cpp
Compile++ thumb  : cv <= cvpyramids.cpp
Compile++ thumb  : cv <= cvpyrsegmentation.cpp
Compile++ thumb  : cv <= cvrotcalipers.cpp
Compile++ thumb  : cv <= cvsamplers.cpp
Compile++ thumb  : cv <= cvsegmentation.cpp
Compile++ thumb  : cv <= cvshapedescr.cpp
Compile++ thumb  : cv <= cvsmooth.cpp
Compile++ thumb  : cv <= cvsnakes.cpp
Compile++ thumb  : cv <= cvstereobm.cpp
Compile++ thumb  : cv <= cvstereogc.cpp
Compile++ thumb  : cv <= cvsubdivision2d.cpp
Compile++ thumb  : cv <= cvsumpixels.cpp
Compile++ thumb  : cv <= cvsurf.cpp
Compile++ thumb  : cv <= cvswitcher.cpp
Compile++ thumb  : cv <= cvtables.cpp
Compile++ thumb  : cv <= cvtemplmatch.cpp
Compile++ thumb  : cv <= cvthresh.cpp
Compile++ thumb  : cv <= cvundistort.cpp
Compile++ thumb  : cv <= cvutils.cpp
StaticLibrary  : libcv.a
SharedLibrary  : libopencv.so
U:/flori/workspace/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3/prebui
lt/windows/bin/../lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-andr
oideabi/bin/ld.exe: cannot find -lcxcore
collect2: ld returned 1 exit status
make: *** [/cygdrive/u/flori/workspace/android/testOpenCV/obj/local/armeabi/libo
pencv.so] Error 1

我正在尝试在 Windows 系统上使用最新的 NDK 版本编译它...

有没有人知道这个链接错误意味着什么以及我可以如何让它再次工作？

如果有人能帮忙就太好了

---

解决问题后，我发现还有另一种为 Android 编译 OpenCV 的方法，使用当前版本的 OpenCV(而不是上面的 1.1 版本)和来自 crystax 的修改后的 Android NDK，它支持 STL 和异常因此支持最新的 OpenCV 版本。

所有相关信息都可以在这里找到: http://opencv.willowgarage.com/wiki/Android

上面说要下载当前的 svn trunk 和 crystax-r4 android-ndk，还有 swig，我照做了。

我进入文件夹，创建构建目录，运行 cmake，然后构建静态库，这似乎工作正常。至少它成功地运行了 make-command 而没有错误。

我现在想构建共享库，所以我进入了 android-jni 文件夹并再次运行“make”，但出现了这个错误:

% make -j4
OPENCV_CONFIG = ../build/android-opencv.mk
make clean-swig &&\
    mkdir -p jni/gen &&\
    mkdir -p src/com/opencv/jni &&\
    swig -java -c++ -package "com.opencv.jni" \
    -outdir src/com/opencv/jni \
    -o jni/gen/android_cv_wrap.cpp jni/android-cv.i
OPENCV_CONFIG = ../build/android-opencv.mk
make[1]: Entering directory `/home/florian/android-opencv-willowgarage/android/android-jni'
make[1]: warning: jobserver unavailable: using -j1.  Add `+' to parent make rule.
rm -f  jni/gen/android_cv_wrap.cpp
make[1]: Leaving directory `/home/florian/android-opencv-willowgarage/android/android-jni'
/home/florian/android-ndk-r4-crystax/ndk-build OPENCV_CONFIG=../build/android-opencv.mk \
    PROJECT_PATH= ARM_TARGETS="armeabi armeabi-v7a" V= 
/home/florian/android-ndk-r4-crystax/ndk-build OPENCV_CONFIG=../build/android-opencv.mk \
    PROJECT_PATH= ARM_TARGETS="armeabi armeabi-v7a" V= 
make[1]: Entering directory `/home/florian/android-opencv-willowgarage/android/android-jni'
/home/florian/android-opencv-willowgarage/android/android-jni/jni/Android.mk:10: ../build/android-opencv.mk: No such file or directory
make[1]: Entering directory `/home/florian/android-opencv-willowgarage/android/android-jni'
/home/florian/android-opencv-willowgarage/android/android-jni/jni/Android.mk:10: ../build/android-opencv.mk: No such file or directory
/home/florian/android-opencv-willowgarage/android/android-jni/jni/Android.mk:10: ../build/android-opencv.mk: No such file or directory
make[1]: warning: jobserver unavailable: using -j1.  Add `+' to parent make rule.
/home/florian/android-opencv-willowgarage/android/android-jni/jni/Android.mk:10: ../build/android-opencv.mk: No such file or directory
make[1]: *** No rule to make target `../build/android-opencv.mk'.  Stop.
make[1]: Leaving directory `/home/florian/android-opencv-willowgarage/android/android-jni'
make: *** [libs/armeabi/libandroid-opencv.so] Error 2
make: *** Waiting for unfinished jobs....
make[1]: warning: jobserver unavailable: using -j1.  Add `+' to parent make rule.
make[1]: *** No rule to make target `../build/android-opencv.mk'.  Stop.
make[1]: Leaving directory `/home/florian/android-opencv-willowgarage/android/android-jni'
make: *** [libs/armeabi-v7a/libandroid-opencv.so] Error 2

有人知道这意味着什么以及我可以做些什么来构建共享库吗？

...

好的，在查看错误消息后，我发现构建目录中似乎缺少某些内容...但是 android 文件夹中甚至没有构建目录，所以我创建了一个，然后运行 ​​' cmake' 并再次'make' 但出现此错误:

Compile thumb  : opencv_lapack <= /home/florian/android-opencv-willowgarage/3rdparty/lapack/sgetrf.c
Compile thumb  : opencv_lapack <= /home/florian/android-opencv-willowgarage/3rdparty/lapack/scopy.c
Compile++ thumb: opencv_core <= /home/florian/android-opencv-willowgarage/modules/core/src/matrix.cpp
cc1plus: error: /home/florian/android-opencv-willowgarage/android/../modules/index.rst/include: Not a directory
make[3]: *** [/home/florian/android-opencv-willowgarage/android/build/obj/local/armeabi/objs/opencv_core/src/matrix.o] Error 1
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [android-opencv] Error 2
make[1]: *** [CMakeFiles/ndk.dir/all] Error 2
make: *** [all] Error 2

有人知道这是什么意思吗？

Answer 1

我刚刚在 Linux 上使用 ndk-r5b 构建了它。您的项目目录(不是 jni)中是否有一个包含如下内容的 default.properties 文件:

target=android-8

如果没有，您可以尝试创建它并重新构建。