NDK(一) hello world

1.NEW一个新的Project

2.app->New->Folder->JNI Folder

3.app/src/main/jni ->New ->Android.mk,Application.mk,hello.cpp

Android.mk:

LOCAL_PATH       :=  $(call my-dir)
include              $(CLEAR_VARS)
LOCAL_MODULE     :=  hello-module
LOCAL_SRC_FILES  :=  hello.cpp
include              $(BUILD_SHARED_LIBRARY)

Application.mk

APP_ABI := armeabi
APP_PLATFORM := android-19

hello.cpp:

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

extern "C"
JNIEXPORT jstring JNICALL
Java_com_movitech_myapplication_MainActivity_hello(JNIEnv *env, jclass type) {
    return env->NewStringUTF("hello world From C.ndk-build");
}

4.build.gradle(app)

defaultConfig {
   
    ndk {
        moduleName "hello-module"
        stl "stlport_static"
        ldLibs "log"
        abiFilters "armeabi"
    }
    sourceSets{
        main{
            jni.srcDirs = []
            jniLibs.srcDir "src/main/libs"
        }
    }
}

5.根据cpp文件生成so文件

6. 调用

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    TextView des = findViewById(R.id.des);
    des.setText(hello());
}


public static native String hello();

static {
    System.loadLibrary("hello-module");
}

7.show