public native int getDoubleNumber(int num);

public native int[] getArrayDoubleNumber(int[] nums);

package com.duicky;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
/**
 * 数据传输
 * 
 * @author luxiaofeng <[email protected]>
 *
 */
public class MainActivity extends Activity {
	
	//也就是你mk配置文件中的  LOCAL_MODULE    := NDK_06
	private static final String libSoName = "NDK_06";
	private Context mContext = null;
	
	private int num = 0;
	private int[] nums;
	
	private Button btnCalculate = null;
	private Button btnCalculateArray = null;
	private EditText etNum = null;
	private EditText etArrayNum = null;
	private TextView tvDoubleNum = null;
	private TextView tvArrayDoubleNum = null;
	
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mContext = this;
        initViews();
    }
    
    /**
     * 初始化控件
     */
    private void initViews() {
		btnCalculate = (Button) findViewById(R.id.btn_calculate);
		btnCalculateArray = (Button) findViewById(R.id.btn_calculate_array);
		etNum = (EditText) findViewById(R.id.et_num);
		etArrayNum = (EditText) findViewById(R.id.et_array_num);
		tvDoubleNum = (TextView) findViewById(R.id.tv_double_num);
		tvArrayDoubleNum = (TextView) findViewById(R.id.tv_array_double_num);
		btnCalculate.setOnClickListener(new MyOnClickListener());
		btnCalculateArray.setOnClickListener(new MyOnClickListener());
	}

    private void calculateArray() {
    	if(getArrayNums()) {
    		setArrayNums();
    	}
	}

	private void calculate() {
		if(getNum()){
			setNum();
		}
	}
	
	private boolean getNum(){
		try{
			num = Integer.valueOf(etNum.getText().toString());
		} catch(NumberFormatException e) {
			etNum.setText("");
			tvDoubleNum.setText("");
			LogUtils.toastMessage(mContext, "输入有误,请重新输入数字");
			return false;
		}
		return true;
	}
	
	private void setNum() {
		int doubleNum = getDoubleNumber(num);
		LogUtils.printWithLogCat("JNIMsg", "C JNI -- >  Java: num = "+doubleNum);
		tvDoubleNum.setText(String.valueOf(doubleNum));
	}
	
	private boolean getArrayNums() {
		String str = etArrayNum.getText().toString();
		if(str.length() <= 0) {
			etArrayNum.setText("");
			tvArrayDoubleNum.setText("");
			LogUtils.toastMessage(mContext, "请按照格式输入");
			return false;
		}
		System.out.println(str);
		if(str.endsWith(".")){
			str = str.substring(0, str.length()-2);
		}
		System.out.println(str);
		String[] strArray = str.split(",");
		int len = strArray.length;
		nums = new int[len];
		for (int i = 0; i < len; i++) {
			try {
				nums[i] = Integer.valueOf(strArray[i]);
				System.out.println(nums[i]);
			} catch(NumberFormatException e) {
				etArrayNum.setText("");
				tvArrayDoubleNum.setText("");
				LogUtils.toastMessage(mContext, "输入有误,请重新输入数组");
				return false;
			}
		}
		return true;
	}
    
	private void setArrayNums() {
		int[] doubleArrayNums = getArrayDoubleNumber(nums);
		
		if(doubleArrayNums == null || doubleArrayNums.length <= 0) {
			LogUtils.toastMessage(mContext, "未转化成功");
			return ;
		}
		
		String str = "";
		for (int i = 0; i < doubleArrayNums.length; i++) {
			str += doubleArrayNums[i] +".";
		}
		str = str.substring(0,str.length()-1);
		tvArrayDoubleNum.setText(str);
	}
	
   class MyOnClickListener implements OnClickListener{

		@Override
		public void onClick(View v) {
			switch(v.getId()) {
				case R.id.btn_calculate:
					calculate();
					break;
				case R.id.btn_calculate_array:
					calculateArray();
					break;
			}
		}
    }

	/**
     * 计算2倍的数字
     * 
     * @param num
     * 
     * @return
     */
    public native int getDoubleNumber(int num);
    
    
    /**
     * 计算2倍的数组值
     * 
     * @param num
     * 
     * @return
     */
    public native int[] getArrayDoubleNumber(int[] nums);
    
    /**
     * 载入JNI生成的so库文件
     */
    static {
        System.loadLibrary(libSoName);
    }
}

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_C_INCLUDES := $(LOCAL_PATH)/include

LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog

LOCAL_MODULE    := NDK_06

LOCAL_SRC_FILES := \

Transmission.c

include $(BUILD_SHARED_LIBRARY)

#include <string.h>
#include <jni.h>
#include <android/log.h>

JNIEnv* jniEnv;


jint
Java_com_duicky_MainActivity_getDoubleNumber( JNIEnv* env,jobject thiz,jint num )
{
	if(jniEnv == NULL) {
		jniEnv = env;
	}
	//获取 Java 传递下来 数字
	__android_log_print(ANDROID_LOG_INFO, "JNIMsg", "Java -- > C JNI : num = %d",num);
	//返回 2 倍 的数字给 Java
	return num*2;
}

jintArray
Java_com_duicky_MainActivity_getArrayDoubleNumber( JNIEnv* env,jobject thiz,jintArray nums )
{
	if(jniEnv == NULL) {
		jniEnv = env;
	}

	if(nums == NULL){
		return NULL;
	}

	//获取 Java 传递下来 数组 的 长度
	jsize len = (*jniEnv)->GetArrayLength(jniEnv, nums);

	__android_log_print(ANDROID_LOG_INFO, "JNIMsg", "Java -- > C JNI : len = %d",len);

	if(len <= 0) {
		return NULL;
	}

	//新建一个长度为len的jintArray数组
	jintArray array = (*jniEnv)-> NewIntArray(jniEnv, len);

	if(array == NULL) {
		return NULL;
	}

	// 把 Java 传递下来的数组 用 jint* 存起来
	jint *body = (*env)->GetIntArrayElements(env, nums, 0);

	jint i = 0;
	jint num[len];
	for (; i < len; i++) {
		num[i] = body[i] * 2;
		__android_log_print(ANDROID_LOG_INFO, "JNIMsg", "Java -- > C JNI : nums[%d] = %d",i,num[i]);
	}

	if(num == NULL){
		return NULL;
	}

	//给 需要返回的数组赋值
	(*jniEnv)->SetIntArrayRegion(jniEnv,array, 0, len, num);

	return array;
}