ndk-构建找不到库

Question

我正在尝试用ndk构建这个示例项目，但由于某种原因，它找不到库。这是我得到的错误消息：

build-binary.mk:688: Android : fastcvFeatDetect依赖于未定义的模块: log GLESv2

我对ndk不太了解，不知道如何检查这些库是否可用，以及我是否正确地指向了它们的路径。

在顶层有一个master文件：

# An Android.mk file must begin with the definition of the LOCAL_PATH variable.
# It is used to locate source files in the development tree. In this example,
# the macro function 'my-dir', provided by the build system, is used to return
# the path of the current directory (i.e. the directory containing the
# Android.mk file itself). 
#
LOCAL_PATH := $(call my-dir) 

JNI_DIR := $(LOCAL_PATH)
UTILS_DIR := $(LOCAL_PATH)/utils

# The function "$(call all-subdir-makefiles)" returns a list of Android.mk 
# files located in all sub-directories of the current 'my-dir' path.
# This function can be used to provide deep-nested source directory
# hierarchies to the build system.
#
include $(call all-subdir-makefiles)

以下是子目录中的生成文件：

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)
LOCAL_PRELINK_MODULE:= false

# This variable determines the OpenGL ES API version to use:
# If set to true, OpenGL ES 1.1 is used, otherwise OpenGL ES 2.0.

USE_OPENGL_ES_1_1 := false

# Set OpenGL ES version-specific settings.

ifeq ($(USE_OPENGL_ES_1_1), true)
    OPENGLES_LIB  := -lGLESv1_CM
    OPENGLES_DEF  := -DUSE_OPENGL_ES_1_1
else
    OPENGLES_LIB  := -lGLESv2
    OPENGLES_DEF  := -DUSE_OPENGL_ES_2_0
endif

# An optional set of compiler flags that will be passed when building
# C ***AND*** C++ source files.
#
# NOTE: flag "-Wno-write-strings" removes warning about deprecated conversion
#       from string constant to 'char*'

LOCAL_CFLAGS := -Wno-write-strings $(OPENGLES_DEF)

# The list of additional linker flags to be used when building your
# module. This is useful to pass the name of specific system libraries
# with the "-l" prefix.

LOCAL_LDLIBS := \
     -llog $(OPENGLES_LIB)
LOCAL_LDFLAGS:= -Wl,--no-fix-cortex-a8

LOCAL_MODULE    := libfastcvFeatDetect
LOCAL_CFLAGS    := -Werror
LOCAL_SRC_FILES := ../About.cpp Corner.cpp

LOCAL_STATIC_LIBRARIES := libfastcv libfastcvUtils
LOCAL_SHARED_LIBRARIES := liblog
LOCAL_C_INCLUDES += $(JNI_DIR)/fastcv
LOCAL_C_INCLUDES += $(JNI_DIR)

LOCAL_MODULE_OWNER := qcom
LOCAL_PROPRIETARY_MODULE := true

include $(BUILD_SHARED_LIBRARY)

我尝试过在谷歌搜索的基础上改变一些东西，但到目前为止都没有效果。有人有什么建议吗？

Answer 1

LOCAL_PRELINK_MODULE:= false

这不是NDK样本。这是平台代码。它是由AOSP构建系统构建的，而不是NDK。有关这方面的更多信息，请参见https://source.android.com/setup/build/building。

如果您想要找到NDK样本，请参见https://github.com/googlesamples/android-ndk。

如果您确实需要使用NDK构建这个非NDK项目，请继续阅读。

在$NDK/build中添加错误消息通常是查找更多信息的好方法：

$(call __ndk_warning,Module $(LOCAL_MODULE) depends on undefined modules: $(undefined_libs))

# https://github.com/android-ndk/ndk/issues/208
# ndk-build didn't used to fail the build for a missing dependency. This
# seems to have always been the behavior, so there's a good chance that
# there are builds out there that depend on this behavior (as of right now,
# anything using libc++ on ARM has this problem because of libunwind).
#
# By default we will abort in this situation because this is so completely
# broken. A user may define APP_ALLOW_MISSING_DEPS to "true" in their
# Application.mk or on the command line to revert to the old, broken
# behavior.
ifneq ($(APP_ALLOW_MISSING_DEPS),true)
    $(call __ndk_error,Aborting (set APP_ALLOW_MISSING_DEPS=true to allow missing dependencies))
endif

这过去常常被默默地忽略，现在它是一个错误。它指出了以下缺陷：

LOCAL_SHARED_LIBRARIES := liblog

这句话什么也做不了。把它删掉。系统库是与LOCAL_LDLIBS而不是LOCAL_SHARED_LIRBARIES链接的。在其他地方也会有类似的行导致GLESv2的错误。