android - 在 android studio 中使用 NDK-BUILD(带有 dlib 库)时，出现以下错误

Question

我正在尝试在项目中使用 dlib、opencv 和 android studio。在执行 ndk-build 时显示以下错误

部分错误

error: undefined reference to dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
error: undefined reference to 'dlib::entropy_decoder_kernel_2::get_target(unsigned int)
 error: undefined reference to 'dlib::entropy_decoder_kernel_2::get_target(unsigned int)
....................
error: undefined reference to 'dlib::base64::decode(std::istream&, std::ostream&) const
 error: undefined reference to 'dlib::base64::~base64()

Android.mk文件内容为

*LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
OPENCV_LIB_TYPE:=STATIC
OPENCV_INSTALL_MODULES:=on
WITH_CUDA=OFF
include /home/sysadmin/ANDROID_PROG_ENVIRONMENTS/OpenCV-android-sdk/sdk/native/jni/OpenCV.mk
LOCAL_C_INCLUDES = $(LOCAL_PATH)
LOCAL_C_INCLUDES +=/home/sysadmin/Android/opencv-3.1.0/modules/imgproc/include
LOCAL_C_INCLUDES +=/home/sysadmin/Android/opencv-3.1.0/modules/core/include
LOCAL_C_INCLUDES +=/home/sysadmin/Android/opencv-3.1.0/modules/calib3d/include/
LOCAL_C_INCLUDES +=/home/sysadmin/Android/opencv-3.1.0/modules/features2d/include/
LOCAL_C_INCLUDES +=/home/sysadmin/Android/opencv-3.1.0/modules/flann/include/
LOCAL_C_INCLUDES +=/dlib/dlib/entropy_decoder_model/
LIBS=/dlib/dlib/
LOCAL_MODULE    := ImageProcessing
LOCAL_SRC_FILES = ImageProcessing.cpp
LOCAL_SRC_FILES += head_pose_estimation.cpp
LOCAL_LDLIBS := -lm -llog -ldl -lz
LDFLAGS =-ldlib
LOCAL_CPPFLAGS +=-lpthread -lX11 -ggdb  -fexceptions -frtti -std=c++11
include $(BUILD_SHARED_LIBRARY)*

Answer 1

在 dlib 源文件夹中的 Android.mk 文件中添加它要求的任何 cpp 文件作为 LOCAL_SRC_FILES。例如，对于您案例中显示的两个链接错误，请执行以下步骤

LOCAL_SRC_FILES += ../dlib/base64/base64_kernel_1.cpp \
                   ../dlib/entropy_decoder/entropy_decoder_kernel_2.cpp \

这些基本上是您的项目期望来自 dlib 的链接错误