如何在Android Studio中配置NDK？

在Android Studio中配置NDK的步骤如下：

1.下载NDK：打开Android Studio，依次点击File -> Project Structure -> SDK Location，在SDK Location窗口中找到Android NDK location，点击Download按钮下载NDK。

2.配置NDK路径：下载完成后，回到SDK Location窗口，将下载好的NDK路径复制到Android NDK location中。

3.配置build.gradle文件：在app目录下的build.gradle文件中添加以下代码：

android {
    ...
    defaultConfig {
        ...
        externalNativeBuild {
            cmake {
                cppFlags ""
                abiFilters ""
            }
        }
    }
    ...
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

4.配置CMakeLists.txt文件：在项目根目录下创建CMakeLists.txt文件，并添加以下代码：

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).
             src/main/cpp/native-lib.cpp )

# Searches for a specified prebuilt library and stores the path as a
# variable. Because system libraries are included 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 the
# 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} )

5.编写C++代码：在app/src/main/cpp目录下创建native-lib.cpp文件，并添加以下代码：

#include <jni.h>
#include <string>

extern "C" JNIEXPORT jstring JNICALL
Java_com_example_ndkdemo_MainActivity_stringFromJNI(
        JNIEnv* env,
        jobject /* this */) {
    std::string hello = "Hello from C++";
    return env->NewStringUTF(hello.c_str());
}

6.运行程序：点击Android Studio中的Run按钮，即可在模拟器或真机上运行程序。