Android NDK JNI开发<3>

换个浏览器来发,IE10不能够上传图片,兼容问题.

还是和上一篇一样的步骤,不过这次函数带了参数:

<1> : eclipse新建一个hellojnidemo3工程,然后将cgywin切换到这个目录下;

<2> : 新建jni文件夹,然后新建.c源码文件,配置文件Android.mk,Application.mk文件,如果不想写了,就照抄以前的内容,改了lib名和c文件名;

Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := jnilib
LOCAL_SRC_FILES := hjni.c

include $(BUILD_SHARED_LIBRARY)

Application.mk

APP_ABI := all

hjni.c

#include<jni.h>
#include<string.h>
jint
Java_com_example_hellojnidemo3_MainActivity_add(JNIEnv* env,jobject thiz,jint va,jint vb){
#if defined(__arm__)
#if defined(__ARM_ARCH_7A__)
#if defined(__ARM_NEON__)
#define ABI "armeabi-v7a/NEON"
#else
#define ABI "armeabi-v7a"
#endif
#else
#define ABI "armeabi"
#endif
#elif defined(__i386__)
#define ABI "x86"
#elif defined(__mips__)
#define ABI "mips"
#else
#define ABI "unknown"
#endif

    return (vb+va);

}

遵循前面讲过的写法,一定不会有问题的.

<3> : Android工程只是做个测试:

package com.example.hellojnidemo3;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

    private Button mAddBtn;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        mAddBtn=(Button)findViewById(R.id.button1);
        mAddBtn.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                Toast.makeText(MainActivity.this, "add = "+ add(12,111),Toast.LENGTH_SHORT).show();
                
            }
            
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
    private native int add(int a,int b);
    
    static{
        System.loadLibrary("jnilib");
    }
    
}

运行结果: