std::string android studio .cpp 文件中的需求错误失败
std::string failed requirement error in android studio .cpp files
我正在尝试通过 NDK 将 C++ 与 Android Studio 集成,但我遇到了如下错误
In instantiation of template class 'std::__ndk1::basic_string<char, std::__ndk1::char_traits<char>, std::__ndk1::allocator<char> >' failed requirement '__is_allocator<std::__ndk1::allocator<char>, void, void>::value'; 'enable_if' cannot be used to disable this declaration
我无法理解错误,也找不到解决方案。
下面是我的代码
原生-lib.cpp
#include <jni.h>
#include <string>
string的位置是C:\User\AppData\Local\Android\Sdk\ndk.0.6113669\toolchains\llvm\prebuilt\windows-x86_64\sysroot\usr\include\c++\v1\string
extern "C" JNIEXPORT jstring JNICALL
Java_com_example_myapplication_MainActivity_stringFromJNI(
JNIEnv* env,
jobject /* this */) {
std::string hello = "Hello from C++";
return env->NewStringUTF(hello.c_str());
}
这是我的 CMakeLists.txt 文件
# documentation: https://d.android.com/studio/projects/add-native-code.html
# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.4.1)
add_library( # Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
native-lib.cpp )
# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.
find_library( # Sets the name of the path variable.
log-lib
# Specifies the name of the NDK library that
# you want CMake to locate.
log )
# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.
target_link_libraries( # Specifies the target library.
native-lib
# Links the target library to the log library
# included in the NDK.
${log-lib} )
这是我的 build.gradle 文件
apply plugin: 'com.android.application'
android {
compileSdkVersion 30
buildToolsVersion "30.0.2"
defaultConfig {
applicationId "com.example.myapplication"
minSdkVersion 23
targetSdkVersion 30
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags "-std=c++11"
}
}
}
ndkVersion '21.0.6113669'
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
cmake {
path "src/main/cpp/CMakeLists.txt"
version "3.10.2"
}
}
}
dependencies {
implementation fileTree(dir: "libs", include: ["*.jar"])
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}
以上是由于文件夹的放置引起的。
NDK 默认放置在 C:/User Name/Android/Sdk/Ndk
User 和 Name 之间的 space 使得很难找到 IDE 的 ndk 文件夹。
将 SDK 转移到另一个位置 C:/Android/Sdk 后,项目成功运行,没有任何错误。
我正在尝试通过 NDK 将 C++ 与 Android Studio 集成,但我遇到了如下错误
In instantiation of template class 'std::__ndk1::basic_string<char, std::__ndk1::char_traits<char>, std::__ndk1::allocator<char> >' failed requirement '__is_allocator<std::__ndk1::allocator<char>, void, void>::value'; 'enable_if' cannot be used to disable this declaration
我无法理解错误,也找不到解决方案。 下面是我的代码
原生-lib.cpp
#include <jni.h>
#include <string>
string的位置是C:\User\AppData\Local\Android\Sdk\ndk.0.6113669\toolchains\llvm\prebuilt\windows-x86_64\sysroot\usr\include\c++\v1\string
extern "C" JNIEXPORT jstring JNICALL
Java_com_example_myapplication_MainActivity_stringFromJNI(
JNIEnv* env,
jobject /* this */) {
std::string hello = "Hello from C++";
return env->NewStringUTF(hello.c_str());
}
这是我的 CMakeLists.txt 文件
# documentation: https://d.android.com/studio/projects/add-native-code.html
# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.4.1)
add_library( # Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
native-lib.cpp )
# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.
find_library( # Sets the name of the path variable.
log-lib
# Specifies the name of the NDK library that
# you want CMake to locate.
log )
# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.
target_link_libraries( # Specifies the target library.
native-lib
# Links the target library to the log library
# included in the NDK.
${log-lib} )
这是我的 build.gradle 文件
apply plugin: 'com.android.application'
android {
compileSdkVersion 30
buildToolsVersion "30.0.2"
defaultConfig {
applicationId "com.example.myapplication"
minSdkVersion 23
targetSdkVersion 30
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags "-std=c++11"
}
}
}
ndkVersion '21.0.6113669'
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
cmake {
path "src/main/cpp/CMakeLists.txt"
version "3.10.2"
}
}
}
dependencies {
implementation fileTree(dir: "libs", include: ["*.jar"])
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}
以上是由于文件夹的放置引起的。 NDK 默认放置在 C:/User Name/Android/Sdk/Ndk User 和 Name 之间的 space 使得很难找到 IDE 的 ndk 文件夹。 将 SDK 转移到另一个位置 C:/Android/Sdk 后,项目成功运行,没有任何错误。