ndk引入
0.配置:
androidstudio :
preferences->Android SDK->SDK Tools 下载NDK +CMake
1590475246611.jpg
1.新项目:
androidstudio :
file->new project->natite c++(下滑才能看见)
2.local.properties
这里查看是否有ndk.dir=/../..
如未有,则添加ndk.dir=/Users/admin/Library/Android/sdk/ndk/../
3.cpp位于main目录下,和java同级
新项目自动创建,老项目创建CMakeLists.txt
创建个xx.cpp
4.MainActivity.java来个方法测试
package main;
import android.app.Activity;
import android.app.ActivityManager;
import android.content.Context;
import android.os.Bundle;
import android.widget.TextView;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import com.zhisheng.test.R;
import java.util.List;
public class MainActivity extends Activity {
static {
System.loadLibrary("native-lib");
}
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.inflate);
(((TextView)(findViewById(R.id.tvTwoJump)))).setText(getStringJNI());
}
public native String getStringJNI();
}
4.cpp来个方法测试
#include <jni.h>
#include <string>
extern "C"
JNIEXPORT jstring JNICALL
//方法名:Java_包名_类名_java调用方法名
//个人理解 c++很少了解
Java_main_MainActivity_getStringJNI(JNIEnv *env, jobject thiz) {
// TODO: implement getStringJNI()
std::string hello = "Hello2222 from C++";
return env->NewStringUTF(hello.c_str());
}
项目测试完成
CMakeLists.txt 上传一下哈
# 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).
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} )
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