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我试图在Android Studio中使用OpenCV与NDK。您可能会注意到我正在使用另一个名为GStreamer的本机库。使用Android NDK构建原生OpenCV给出“未定义的引用''cv :: String :: deallocate（）''
我的build.gradle：
apply plugin: 'com.android.application'
def getNdkCommandLine(ndkRoot, target) {
def gstRoot
def opencvRoot
gstRoot = 'C:/local/gstreamer-1.0-android-arm-1.8.0'
opencvRoot = 'C:/local/OpenCV-3.1.0-android-sdk/OpenCV-android-sdk'
if (ndkRoot == null)
throw new GradleException('NDK not configured')
return ["$ndkRoot/ndk-build.cmd",
'NDK_PROJECT_PATH=build',
'APP_BUILD_SCRIPT=src/main/jni/Android.mk',
'NDK_APPLICATION_MK=src/main/jni/Application.mk',
'GSTREAMER_JAVA_SRC_DIR=src/main/java',
"GSTREAMER_ROOT_ANDROID=$gstRoot",
"OPENCV_ROOT_ANDROID=$opencvRoot",
"$target"]
}
android {
compileSdkVersion 19
buildToolsVersion "23.0.2"
sourceSets {
main {
// Avoid using the built in JNI generation plugin
jni.srcDirs = []
jniLibs.srcDirs = ['build/libs']
}
}
defaultConfig {
applicationId "com.mytestcom.mytestapp"
minSdkVersion 19
targetSdkVersion 19
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_7
targetCompatibility JavaVersion.VERSION_1_7
}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
signingConfig signingConfigs.release
}
}
// Before compiling our app, prepare NDK code
tasks.withType(JavaCompile) {
compileTask -> compileTask.dependsOn ndkBuild
}
// Need to call clean on NDK ourselves too
clean.dependsOn 'ndkClean'
// Build native code using mk files like on Eclipse
task ndkBuild(type: Exec, description: 'Compile JNI source via NDK') {
commandLine getNdkCommandLine(android.ndkDirectory, 'TARGET_ARCH_ABI=armeabi-v7a')
}
task ndkClean(type: Exec, description: 'Clean JNI code built via NDK') {
commandLine getNdkCommandLine(android.ndkDirectory, 'clean')
}
//Renames APK to current versionName found in Android Manifest
applicationVariants.all { variant ->
variant.outputs.each { output ->
def outputFile = output.outputFile
if (outputFile != null && outputFile.name.endsWith('.apk')) {
def fileName = "My_Test_App-${versionName}.apk"
output.outputFile = new File(outputFile.parent, fileName)
}
}
}
}
dependencies {
compile 'com.android.support:support-v4:19.1.0'
compile project(':openCVLibrary310')
}
Android.mk：
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := gstplayer
LOCAL_SRC_FILES := player.cpp
LOCAL_C_INCLUDES := $(OPENCV_ROOT_ANDROID)/sdk/native/jni/include
LOCAL_SHARED_LIBRARIES := gstreamer_android
LOCAL_LDLIBS := -llog -landroid
include $(BUILD_SHARED_LIBRARY)
ifeq ($(TARGET_ARCH_ABI),armeabi)
GSTREAMER_ROOT := $(GSTREAMER_ROOT_ARM)
else ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
GSTREAMER_ROOT := $(GSTREAMER_ROOT_ARMV7)
else ifeq ($(TARGET_ARCH_ABI),arm64-v8a)
GSTREAMER_ROOT := $(GSTREAMER_ROOT_ARM64)
else ifeq ($(TARGET_ARCH_ABI),x86)
GSTREAMER_ROOT := $(GSTREAMER_ROOT_X86)
else ifeq ($(TARGET_ARCH_ABI),x86_64)
GSTREAMER_ROOT := $(GSTREAMER_ROOT_X86_64)
else
$(error Target arch ABI not supported)
endif
ifndef GSTREAMER_ROOT
ifndef GSTREAMER_ROOT_ANDROID
$(error GSTREAMER_ROOT_ANDROID is not defined!)
endif
GSTREAMER_ROOT := $(GSTREAMER_ROOT_ANDROID)
endif
GSTREAMER_NDK_BUILD_PATH := $(GSTREAMER_ROOT)/share/gst-android/ndk-build/
include $(GSTREAMER_NDK_BUILD_PATH)/plugins.mk
GSTREAMER_PLUGINS := $(GSTREAMER_PLUGINS_CORE) $(GSTREAMER_PLUGINS_PLAYBACK) $(GSTREAMER_PLUGINS_CODECS) $(GSTREAMER_PLUGINS_NET) $(GSTREAMER_PLUGINS_SYS) $(GSTREAMER_PLUGINS_CODECS_RESTRICTED) $(GSTREAMER_CODECS_GPL) $(GSTREAMER_PLUGINS_ENCODING) $(GSTREAMER_PLUGINS_VIS) $(GSTREAMER_PLUGINS_EFFECTS) $(GSTREAMER_PLUGINS_NET_RESTRICTED)
GSTREAMER_EXTRA_DEPS := gstreamer-player-1.0 gstreamer-video-1.0 glib-2.0
OPENCV_INSTALL_MODULES:=on
OPENCV_CAMERAMODULES:=off
OPENCV_LIB_TYPE:=STATIC
include $(GSTREAMER_NDK_BUILD_PATH)/gstreamer-1.0.mk
include $(OPENCV_ROOT_ANDROID)/sdk/native/jni/OpenCV.mk
Application.mk：
APP_PLATFORM=android-19
APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
我使用的OpenCV-3.1.0-android- sdk，NDK r10e，Android Studio 2.1，Windows。我试过使用不同版本的OpenCV（2.4.11），但它没有帮助。
C:\local\OpenCV-3.1.0-android-sdk\OpenCV-android-sdk\sdk\native\jni\include\opencv2\core\cvstd.hpp
Error:(625) undefined reference to 'cv::String::allocate(unsigned int)'
Error:(667) undefined reference to 'cv::String::deallocate()'
Error:(667) undefined reference to 'cv::String::deallocate()'
Error:(667) undefined reference to 'cv::String::deallocate()'
Error:(667) undefined reference to 'cv::String::deallocate()'
C:\local\OpenCV-3.1.0-android-sdk\OpenCV-android-sdk\sdk\native\jni\include\opencv2\core\mat.inl.hpp
Error:(443) undefined reference to 'cv::error(int, cv::String const&, char const*, char const*, int)'
Error:(459) undefined reference to 'cv::error(int, cv::String const&, char const*, char const*, int)'
Error:(682) undefined reference to 'cv::Mat::deallocate()'
Error:(571) undefined reference to 'cv::fastFree(void*)'
Error:(592) undefined reference to 'cv::Mat::copySize(cv::Mat const&)'
改变
APP_STL := gnustl_static到APP_STL := gnustl_shared我相信这个问题是正在使用的.HPP文件需要外部库建成并链接到。例如，** libopencv_core.a **。因此，在[this]（https://developer.android.com/ndk/guides/prebuilts.html）链接之后，我添加了一个部分给我的Android.mk文件，该文件应该添加一个模块作为'PREBUILT_STATIC_LIBRARY'。我已经修复了由于这个添加而导致的所有错误，但是我回到了之前的错误（undefined reference to ...） – MarkyDD这是确定的。我没有看到应用程序链接的库的任何设置。 –