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新建一个NDK项目,没有的自动下载
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要勾选IncludeC++ support，之后的选项都是默认的， 不需要在勾选什么配置。
BuildProject的时候可能会出现Build失败的情况，可能是cmake没有下载。在sdk tools里面下载重新Build项目即可。
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新增的目录结构
新增的文件
.externalNativeBuild文件夹不用管，系统自动生成的
cpp文件夹，包含的c文件，可自行创建或者修改代码
CMakeList.txt文件是cmake的配置文件
- CMakeList.txt
# For more information about using CMake with Android Studio, read the
# 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)
# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.
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 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} )
有关于CMakeList.txt文件需要注意的是：
add_library：创建一个library，添加C/C++文件；find_library：表示依赖NDK中的库，一般不需要手动去更改；target_link_libraries：表示将目标库与NDK中的库进行连接。如果有多个库时，可以添加多个add_library和target_link_libraries。
生成的文件，基本就介绍完了。再看看build.gradle新增的
compileSdkVersion 26
defaultConfig {
applicationId "com.example.administrator.myapplication"
minSdkVersion 26
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
//新增的NDK，默认是空串，如果要自定义，这边需要修改
externalNativeBuild {
cmake {
cppFlags ""
}
}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {//新增的NDK
cmake {
path "CMakeLists.txt"
}
}
- MainActivity的调用
public class MainActivity extends AppCompatActivity {
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");//这个是cpp里面使用的lib名称，以及cmake里面配置的名称
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Example of a call to a native method
TextView tv = (TextView) findViewById(R.id.sample_text);
tv.setText(stringFromJNI());
}
/**
* A native method that is implemented by the 'native-lib' native library,
* which is packaged with this application.
*/
public native String stringFromJNI();//这个是native-lib里面的方法名称
}
这就是简单的构建，如果需要开发的话，需要个人学习c语言
