基于Android studio3.6的JNI教程之helloworld思路详解

E:\Android\Android Studio\jre\bin
E:\Android\Android Studio\bin

package com.example.myapplication;
 
public class hello {
 public native int add(int i, int j);
}

#include <jni.h>
/* Header for class com_example_myapplication_hello */
 
#ifndef _Included_com_example_myapplication_hello
#define _Included_com_example_myapplication_hello
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class: com_example_myapplication_hello
 * Method: add
 * Signature: (II)I
 */
 
#include "com_example_myapplication_hello.h"
 
JNIEXPORT jint JNICALL Java_com_example_myapplication_hello_add
 (JNIEnv *, jobject, jint i, jint j){return i+j;}
 
#ifdef __cplusplus
}
#endif
#endif

add_library( # Sets the name of the library.
 hello
 
 # Sets the library as a shared library.
 SHARED
 
 # Provides a relative path to your source file(s).
 hello.cpp )

target_link_libraries( # Specifies the target library.
  native-lib
  hello
  # Links the target library to the log library
  # included in the NDK.
  ${log-lib} )

package com.example.myapplication;
 
public class hello {
 
 static {
 System.loadLibrary("hello");
 }
 public native int add(int i, int j);
}

protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 
 // Example of a call to a native method
 TextView tv = findViewById(R.id.sample_text);
 //tv.setText(stringFromJNI());
 tv.setText("hello 9+10= " + new hello().add(9, 10));
 }