Android的jni的调用C,C++的几个应用(基本类型，数组，类(结构体))

今天是母亲节，首先祝愿全天下的母亲健康长寿！永远年轻！天天快乐！
慈母手中线，游子身上衣，临行密密缝，意恐迟迟归，谁言寸草心，报得三春晖。
谢谢妈妈--jernymy

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开始正题啦，前些天在研究Andorid中Jni(Java Native Interface)的使用，
主要是在android中调用C、C++的方法，在网上也搜集了一些文档，源码等资料，非常感谢网友的提供的宝贵经验。
也是写下这个文章，希望可以帮助正在做这方面应用网友们，jni使用c语言。

一、首先软件环境要搭配好，本人使用的环境是
Android2.2的SDK+NDK4b，linux下的编译环境
1. Windows XP
2. VMware 7.1.3 build-324285 + Ubuntu 9.04中文版
3. Android SDK 2.2

4. Android NDK r4b Linux版(crystax)，加入支持C++ exceptions, RTTI and Standard C++ Library
http://www.crystax.net/android/ndk-r4.php
http://www.crystax.net/data/android-ndk-r4-linux-x86-crystax-4.tar.bz2

5. Eclipse Version: 3.5.2
eclipse3.5.2官方下载地址
http://archive.eclipse.org/eclipse/downloads/drops/R-3.5.2-201002111343/eclipse-SDK-3.5.2-win32.zip

二、配置好eclipse，并加入androiddSDK，然后通过eclipse建立一个android工程，搭建android的jni框架
1. Eclipse
File->New->Android Project
如果此地没有Android Project，可以通过File->New->Project...，在弹出的对话框中，选择(Android)
以下几项填写，其他的默认即可
Project name: AndroidJni
Build Target: Android 2.2
Application name: AndroidJni
Package name: com.jni
Create Activity: AndroidJni
Min SDK Version: 8
点击Finish即可

此时，我们就可以看到我们的项目了
在src->com.jni下自动生成的AndroidJni.java内容如下

我们在这里新建立一个class，比如命名jernymyjni，
这个作为我们的Jni的所有接口处，作为测试设计了基本类型，数组，和类(结构体)，结构体数组等。
代码如下package com.jni; // jernymy use c style for var name public class jernymyjni { char chChar; // char use ch token // short wShort; // short use w token, short same as int int nInt; // int use n token String sString; // String use s token /*-------- jernymy for base type declaration start --------*/ /* * The char process method GetChar * @param char chInput : the input char for process * @return(char) : input char (chInput) upper or lower * @author : jernymy * @date : 20110508 * */ public native char GetChar(char chInput); /* * The char process method SetChar * @param char chInput : set the input char * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetChar(char chInput); /* * The int process method GetInt * @param int nAdd1 : add one * @param int nAdd2 : add other * @return(int) : sum of two add var * @author : jernymy * @date : 20110508 * */ public native int GetInt(int nAdd1, int nAdd2); /* * The int process method SetInt * @param int nSet : set one int data * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetInt(int nSet); /* * The String process method GetStr * @return(String) : the string for use * @author : jernymy * @date : 20110508 * */ public native String GetStr(); /* * The String process method PrcsStr * @param String sInput : the input String for process * @return(String) : the process of the input String * @author : jernymy * @date : 20110508 * */ public native String PrcsStr(String sInput); /* * The String process method PrcsStr * @param String sSet : the set String * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetStr(String sSet); /*-------- jernymy for base type declaration end --------*/ /*-------- jernymy for array type declaration start --------*/ /* * The char array process method GetCharArray * @param char chSet : the chSet char for process * @return(char[]) : char array, upper and lower * @author : jernymy * @date : 20110508 * */ public native char[] GetCharArray(char chSet); /* * The char array process method SetCharArray * @param char[] chSet : the chSet char array for process * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetCharArray(char[] chSet); /* * The int array process method GetIntArray * @param int[] nAdd1 : add one array * @param int[] nAdd2 : add other array * @return(int[]) : sum array of two add array var * @author : jernymy * @date : 20110508 * */ public native int[] GetIntArray(int[] nAdd1, int[] nAdd2); /* * The int array process method SetIntArray * @param int[] nSet : set one int array data * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetIntArray(int[] nSet); /* * The String array process method GetStrArray * @return(String[]) : String array with null parameter * @author : jernymy * @date : 20110508 * */ public native String[] GetStrArray(); /* * The String array process method PrcsStrArray * @param String sSet : the string with " " token sSet * @return(String[]) : ervey string by " " token * @author : jernymy * @date : 20110508 * */ public native String[] PrcsStrArray(String sSet); /* * The String array process method SetStrArray * @param String[] sSet : set the string array * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetStrArray(String[] sSet); /*-------- jernymy for array type declaration end --------*/ /*-------- jernymy for class(struct) type declaration start --------*/ /* * The jernymyjni class(struct) process method GetClass * @param int nIdx : get class data by index * @return(jernymyjni) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native jernymyjni GetClass(int nIdx); /* * The jernymyjni class(struct) process method SetClass * @param jernymyjni cClass : set class data by class index * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetClass(jernymyjni cClass); /*-------- jernymy for class(struct) type declaration end --------*/ /*-------- jernymy for class(struct) array type declaration start --------*/ /* * The jernymyjni class(struct) array process method GetClassArray * @return(jernymyjni[]) : class array data * @author : jernymy * @date : 20110508 * */ public native jernymyjni[] GetClassArray(); /* * The jernymyjni class(struct) array process method SetClassArray * @param jernymyjni[] cNcomnAry : set class array data * @return(int) : status, 0-OK, other-Error * @author : jernymy * @date : 20110508 * */ public native int SetClassArray(jernymyjni[] acClassAry); /*-------- jernymy for class(struct) array type declaration end --------*/ static { System.loadLibrary("jernymyjni"); // jernymy here is the so name } }

通过eclipse的生成对应的class文件，会在AndroidJni/bin下生成所有的文件

然后进入windowsXP的command模式
开始->运行->cmd
到我们的项目的所在目录，我的目录为
运行javah，得到对应的jni的头文件
E:/work/jave/workspace/AndroidJni>javah -classpath bin com.jni.jernymyjni

E:/work/jave/workspace/AndroidJni>
此时会在当前目录下生成一个com_jni_jernymyjni.h，好了，就是它了，接下来开始编写它对应的c文件了。
为了符合android的文档规范，我们需要在当前目录(AndroidJni)下先建立一个jni目录，然后再建立一个Android.mk
然后把com_jni_jernymyjni.h文件copy到jni目录下。

E:/work/jave/workspace/AndroidJni>cd jni

E:/work/jave/workspace/AndroidJni/jni>dir
驱动器 E 中的卷是 work
卷的序列号是 1C8F-CA73

E:/work/jave/workspace/AndroidJni/jni 的目录

2011-05-08 23:09 <DIR> .
2011-05-08 23:09 <DIR> ..
2011-05-08 23:08 0 Android.mk
2011-05-08 22:58 3,802 com_jni_jernymyjni.h
2 个文件 3,802 字节
2 个目录 10,864,427,008 可用字节

E:/work/jave/workspace/AndroidJni/jni>

com_jni_jernymyjni.h的文件内容
/* DO NOT EDIT THIS FILE - it is machine generated */ #include <jni.h> /* Header for class com_jni_jernymyjni */ #ifndef _Included_com_jni_jernymyjni #define _Included_com_jni_jernymyjni #ifdef __cplusplus extern "C" { #endif /* * Class: com_jni_jernymyjni * Method: GetChar * Signature: (C)C */ JNIEXPORT jchar JNICALL Java_com_jni_jernymyjni_GetChar (JNIEnv *, jobject, jchar); /* * Class: com_jni_jernymyjni * Method: SetChar * Signature: (C)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetChar (JNIEnv *, jobject, jchar); /* * Class: com_jni_jernymyjni * Method: GetInt * Signature: (II)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_GetInt (JNIEnv *, jobject, jint, jint); /* * Class: com_jni_jernymyjni * Method: SetInt * Signature: (I)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetInt (JNIEnv *, jobject, jint); /* * Class: com_jni_jernymyjni * Method: GetStr * Signature: ()Ljava/lang/String; */ JNIEXPORT jstring JNICALL Java_com_jni_jernymyjni_GetStr (JNIEnv *, jobject); /* * Class: com_jni_jernymyjni * Method: PrcsStr * Signature: (Ljava/lang/String;)Ljava/lang/String; */ JNIEXPORT jstring JNICALL Java_com_jni_jernymyjni_PrcsStr (JNIEnv *, jobject, jstring); /* * Class: com_jni_jernymyjni * Method: SetStr * Signature: (Ljava/lang/String;)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetStr (JNIEnv *, jobject, jstring); /* * Class: com_jni_jernymyjni * Method: GetCharArray * Signature: (C)[C */ JNIEXPORT jcharArray JNICALL Java_com_jni_jernymyjni_GetCharArray (JNIEnv *, jobject, jchar); /* * Class: com_jni_jernymyjni * Method: SetCharArray * Signature: ([C)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetCharArray (JNIEnv *, jobject, jcharArray); /* * Class: com_jni_jernymyjni * Method: GetIntArray * Signature: ([I[I)[I */ JNIEXPORT jintArray JNICALL Java_com_jni_jernymyjni_GetIntArray (JNIEnv *, jobject, jintArray, jintArray); /* * Class: com_jni_jernymyjni * Method: SetIntArray * Signature: ([I)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetIntArray (JNIEnv *, jobject, jintArray); /* * Class: com_jni_jernymyjni * Method: GetStrArray * Signature: ()[Ljava/lang/String; */ JNIEXPORT jobjectArray JNICALL Java_com_jni_jernymyjni_GetStrArray (JNIEnv *, jobject); /* * Class: com_jni_jernymyjni * Method: PrcsStrArray * Signature: (Ljava/lang/String;)[Ljava/lang/String; */ JNIEXPORT jobjectArray JNICALL Java_com_jni_jernymyjni_PrcsStrArray (JNIEnv *, jobject, jstring); /* * Class: com_jni_jernymyjni * Method: SetStrArray * Signature: ([Ljava/lang/String;)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetStrArray (JNIEnv *, jobject, jobjectArray); /* * Class: com_jni_jernymyjni * Method: GetClass * Signature: (I)Lcom/jni/jernymyjni; */ JNIEXPORT jobject JNICALL Java_com_jni_jernymyjni_GetClass (JNIEnv *, jobject, jint); /* * Class: com_jni_jernymyjni * Method: SetClass * Signature: (Lcom/jni/jernymyjni;)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetClass (JNIEnv *, jobject, jobject); /* * Class: com_jni_jernymyjni * Method: GetClassArray * Signature: ()[Lcom/jni/jernymyjni; */ JNIEXPORT jobjectArray JNICALL Java_com_jni_jernymyjni_GetClassArray (JNIEnv *, jobject); /* * Class: com_jni_jernymyjni * Method: SetClassArray * Signature: ([Lcom/jni/jernymyjni;)I */ JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetClassArray (JNIEnv *, jobject, jobjectArray); #ifdef __cplusplus } #endif #endif

com_jni_jernymyjni.c的文件内容

#include "com_jni_jernymyjni.h" #include "stdio.h" // printf #include "string.h" // strlen, memset... #define JNI_ERR_NULL_CLASS 0x10 #define JNI_ERR_NULL_CHAR 0x11 #define JNI_ERR_NULL_INT 0x12 #define JNI_ERR_NULL_STR 0x13 #define JNI_ERR_NULL_OBJ 0x14 #define JNI_ERR_NULL_FIELD_CHAR 0x15 #define JNI_ERR_NULL_FIELD_INT 0x16 #define JNI_ERR_NULL_FIELD_OBJ 0x17 #define JNI_ERR_NULL_STR_UTF_C 0x18 #define JNI_ERR_NULL_OBJ_ARY_ELEMENT 0x19 #define JNI_ERR_NULL_METHOD 0x20 #define JNI_DBG printf("[C]-File:%s, Line:%d/n", __FILE__, __LINE__); #define JNI_ASSERT_P_RTN_VAR(var, rtn)/ if (NULL == var)/ {/ printf("[C]-File:%s, Line:%d, %s==NULL/n", __FILE__, __LINE__, #var);/ return rtn;/ } #define JNI_ASSERT_V_RTN_VAR(var, rtn)/ if (0 == var)/ {/ printf("[C]-File:%s, Line:%d, %s==NULL/n", __FILE__, __LINE__, #var);/ return rtn;/ } FILE *fpJniDbg = NULL; // A[65], a[97] // (chA1 & (~0x20)) = tower, (chA1 | 0x20)upper JNIEXPORT jchar JNICALL Java_com_jni_jernymyjni_GetChar (JNIEnv *jpcEnv, jobject jcObj, jchar jchInput) { if (jchInput >= 'a' && jchInput <= 'z') { return (jchInput & (~0x20)); } else if (jchInput >= 'A' && jchInput <= 'Z') { return (jchInput | 0x20); } return 0; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetChar (JNIEnv *jpcEnv, jobject jcObj, jchar jchSet) { printf("[C]-Line:%d-Java_com_jni_jernymyjni_SetChar-jchSet:%c/n", __LINE__, jchSet); return 0; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_GetInt (JNIEnv *jpcEnv, jobject jcObj, jint jnAdd1, jint jnAdd2) { return (jnAdd1 + jnAdd2); } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetInt (JNIEnv *jpcEnv, jobject jcObj, jint jnSet) { printf("[C]-Line:%d-Java_com_jni_jernymyjni_SetInt-jnSet:%d/n", __LINE__, jnSet); return 0; } JNIEXPORT jstring JNICALL Java_com_jni_jernymyjni_GetStr (JNIEnv *jpcEnv, jobject jcObj) { char *pachStr = {"Jernymy jni test"}; return (*jpcEnv)->NewStringUTF(jpcEnv, pachStr); } JNIEXPORT jstring JNICALL Java_com_jni_jernymyjni_PrcsStr (JNIEnv *jpcEnv, jobject jcObj, jstring jsStr) { int nLen = 0; char achBuf[128] = {0}; const char *lpcstrGet = (*jpcEnv)->GetStringUTFChars(jpcEnv, jsStr, 0); nLen = strlen(lpcstrGet); nLen = (nLen > 127) ? 127 : nLen; strncpy(achBuf, lpcstrGet, nLen); (*jpcEnv)->ReleaseStringUTFChars(jpcEnv, jsStr, lpcstrGet); while (nLen--) { // swicth to upper, to lower (a &(~0x20)) achBuf[nLen] = achBuf[nLen] | 0x20; } return (*jpcEnv)->NewStringUTF(jpcEnv, achBuf); } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetStr (JNIEnv *jpcEnv, jobject jcObj, jstring jsStr) { const char *lpcstrGet = (*jpcEnv)->GetStringUTFChars(jpcEnv, jsStr, 0); JNI_ASSERT_P_RTN_VAR(lpcstrGet, -1); printf("[C]-Line:%d-Java_com_jni_jernymyjni_SetStr-jsStr:%s/n", __LINE__, lpcstrGet); // release for memory (*jpcEnv)->ReleaseStringUTFChars(jpcEnv, jsStr, lpcstrGet); return 0; } #define CHAR_NUM 2 JNIEXPORT jcharArray JNICALL Java_com_jni_jernymyjni_GetCharArray (JNIEnv *jpcEnv, jobject jcObj, jchar jchChar) { jobjectArray joArray = 0; jchar achBuf[CHAR_NUM] = {0}; achBuf[0] = jchChar & (~0x20); // 'a' achBuf[1] = jchChar | 0x20; // 'A' joArray = (*jpcEnv)->NewCharArray(jpcEnv, CHAR_NUM); JNI_ASSERT_P_RTN_VAR(joArray, NULL); (*jpcEnv)->SetCharArrayRegion(jpcEnv, joArray, 0, 2, achBuf); return joArray; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetCharArray (JNIEnv *jpcEnv, jobject jcObj, jcharArray jchCharArray) { jsize jsLen = (*jpcEnv)->GetArrayLength(jpcEnv, jchCharArray); // get array length printf("[C]-Line:%d-Java_com_jni_jernymyjni_SetCharArray-jsLen:%d,jchCharArray:%p/n", __LINE__, jsLen, jchCharArray); return 0; } JNIEXPORT jintArray JNICALL Java_com_jni_jernymyjni_GetIntArray (JNIEnv *jpcEnv, jobject jcObj, jintArray jiAry1, jintArray jiAry2) { int nIdx; jint nSum[10] = {0}; jobjectArray joArray = 0; jsize jsLen = (*jpcEnv)->GetArrayLength(jpcEnv, jiAry1); // get array length jint *jpIAry1 = (*jpcEnv)->GetIntArrayElements(jpcEnv, jiAry1, 0); // get array element pointer jint *jpIAry2 = (*jpcEnv)->GetIntArrayElements(jpcEnv, jiAry2, 0); // get array element pointer // the value is now valid, so return NULL JNI_ASSERT_V_RTN_VAR(jsLen, NULL); JNI_ASSERT_P_RTN_VAR(jpIAry1, NULL); JNI_ASSERT_P_RTN_VAR(jpIAry2, NULL); printf("[C]-Line:%d-Java_com_jni_jernymyjni_GetIntArray-jiAry1 length:%d/n", __LINE__, jsLen); joArray = (*jpcEnv)->NewIntArray(jpcEnv, jsLen); JNI_ASSERT_P_RTN_VAR(joArray, NULL); for (nIdx = 0; nIdx < jsLen; nIdx++) { nSum[nIdx] = jpIAry1[nIdx] + jpIAry2[nIdx]; // add every array element printf("[C]-nSum:%d=%d+%d/n", nSum[nIdx], jpIAry1[nIdx], jpIAry2[nIdx]); } (*jpcEnv)->SetIntArrayRegion(jpcEnv, joArray, 0, jsLen, nSum); (*jpcEnv)->ReleaseIntArrayElements(jpcEnv, jiAry1, jpIAry1, 0); // release, do not forget (*jpcEnv)->ReleaseIntArrayElements(jpcEnv, jiAry2, jpIAry2, 0); // release, do not forget return joArray; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetIntArray (JNIEnv *jpcEnv, jobject jcObj, jintArray jiAry1) { int nIdx; jsize jsLen = (*jpcEnv)->GetArrayLength(jpcEnv, jiAry1); // get array length jint *jpIAry1 = (*jpcEnv)->GetIntArrayElements(jpcEnv, jiAry1, 0); // get array pointer JNI_ASSERT_V_RTN_VAR(jsLen, 0); JNI_ASSERT_P_RTN_VAR(jpIAry1, 0); printf("[C]-Line:%d-Java_com_jni_jernymyjni_GetIntArray-jiAry1 length:%d/n", __LINE__, jsLen); for (nIdx = 0; nIdx < jsLen; nIdx++) { printf("[C]-Index:%d, jpIAry1:%d/n", nIdx, jpIAry1[nIdx]); } (*jpcEnv)->ReleaseIntArrayElements(jpcEnv, jiAry1, jpIAry1, 0); // release, do not forget return 0; } #define JNI_STR_ARRAY_NUM 3 JNIEXPORT jobjectArray JNICALL Java_com_jni_jernymyjni_GetStrArray (JNIEnv *jpcEnv, jobject jcObj) { jstring jsStr = 0; jclass jcStrCls = 0; jobjectArray joArray = 0; int nIdx = 0; char *pachStr[JNI_STR_ARRAY_NUM] = {"Jernymy", "Jni ", "Test"}; jcStrCls = (*jpcEnv)->FindClass(jpcEnv, "java/lang/String"); JNI_ASSERT_P_RTN_VAR(jcStrCls, NULL); joArray = (*jpcEnv)->NewObjectArray(jpcEnv, JNI_STR_ARRAY_NUM, jcStrCls, 0); JNI_ASSERT_P_RTN_VAR(joArray, NULL); for (; nIdx< JNI_STR_ARRAY_NUM; nIdx++) { jsStr = (*jpcEnv)->NewStringUTF(jpcEnv, pachStr[nIdx]); JNI_ASSERT_P_RTN_VAR(jsStr, NULL); (*jpcEnv)->SetObjectArrayElement(jpcEnv, joArray, nIdx, jsStr); } return joArray; } JNIEXPORT jobjectArray JNICALL Java_com_jni_jernymyjni_PrcsStrArray (JNIEnv *jpcEnv, jobject jcObj, jstring jsString) { jobjectArray joArray = 0; jclass jcStrCls; jstring jsCurStr; const char *lpcstrGet; const char *lpcstrBk; char *pchStr; char achStrBuf[128] = {0}; int nIndex = 0; pchStr = achStrBuf; #ifdef WIN32 // OK success - win32 system // win32 "java/lang/String" and "Ljava/lang/String;" both OK // jclass jcStrCls = (*jpcEnv)->FindClass(jpcEnv, "java/lang/String"); jcStrCls = (*jpcEnv)->FindClass(jpcEnv, "Ljava/lang/String;"); #else // linux here must "java/lang/String" jcStrCls = (*jpcEnv)->FindClass(jpcEnv, "java/lang/String"); /* ----get string array: Exception in thread "main" java.lang.ClassNotFoundException: Ljava.lang.String; not found in gnu.gcj.runtime.SystemClassLoader{urls=[file:./], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}} at java.net.URLClassLoader.findClass(libgcj.so.7rh) at gnu.gcj.runtime.SystemClassLoader.findClass(libgcj.so.7rh) at java.lang.ClassLoader.loadClass(libgcj.so.7rh) at java.lang.ClassLoader.loadClass(libgcj.so.7rh) [yewu@localhost src]$ */ // jclass jcStrCls = (*jpcEnv)->FindClass(jpcEnv, "Ljava/lang/String;"); #endif JNI_ASSERT_P_RTN_VAR(jcStrCls, NULL); joArray = (*jpcEnv)->NewObjectArray(jpcEnv, 3, jcStrCls, 0); JNI_ASSERT_P_RTN_VAR(joArray, NULL); lpcstrGet = (*jpcEnv)->GetStringUTFChars(jpcEnv, jsString, 0); JNI_ASSERT_P_RTN_VAR(lpcstrGet, NULL); lpcstrBk = lpcstrGet; printf("[C]-lpcstrGet:%s/n", lpcstrGet); while (*lpcstrGet) { if (' ' == *lpcstrGet) { nIndex++; lpcstrGet++; printf("[C]-achStrBuf:%s/n", achStrBuf); jsCurStr = (*jpcEnv)->NewStringUTF(jpcEnv, achStrBuf); JNI_ASSERT_P_RTN_VAR(jsCurStr, NULL); (*jpcEnv)->SetObjectArrayElement(jpcEnv, joArray, nIndex-1, jsCurStr); memset(&achStrBuf, 0, 128); pchStr = &achStrBuf[0]; } else { *pchStr++ = *lpcstrGet++; } } if (achStrBuf[0]) { printf("[C]-achStrBuf:%s/n", achStrBuf); jsCurStr = (*jpcEnv)->NewStringUTF(jpcEnv, achStrBuf); JNI_ASSERT_P_RTN_VAR(jsCurStr, NULL); (*jpcEnv)->SetObjectArrayElement(jpcEnv, joArray, nIndex, jsCurStr); } (*jpcEnv)->ReleaseStringUTFChars(jpcEnv, jsString, lpcstrBk); return joArray; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetStrArray (JNIEnv *jpcEnv, jobject jcObj, jobjectArray jcObjAry) { int nIdx; const char *lpcstrGet; jobject jcObjCur; int nLen = (*jpcEnv)->GetArrayLength(jpcEnv, jcObjAry); JNI_ASSERT_V_RTN_VAR(nLen, 0); printf("[C]-jcObjAry length:%d/n", nLen); for (nIdx = 0; nIdx < nLen; nIdx++) { jcObjCur = (*jpcEnv)->GetObjectArrayElement(jpcEnv, jcObjAry, nIdx); JNI_ASSERT_P_RTN_VAR(jcObjCur, 0); lpcstrGet = (*jpcEnv)->GetStringUTFChars(jpcEnv, (jstring)jcObjCur, 0 ); JNI_ASSERT_P_RTN_VAR(lpcstrGet, 0); printf("[C]-index[%d] lpcstrGet:%s/n", nIdx, lpcstrGet); (*jpcEnv)->ReleaseStringUTFChars(jpcEnv, jcObjCur, lpcstrGet); } printf("[C]-/n"); return 0; } JNIEXPORT jobject JNICALL Java_com_jni_jernymyjni_GetClass (JNIEnv *jpcEnv, jobject jcObj, jint jnIdx) { char achBuf[32] = {0}; jclass jcStruct; jfieldID jchChar; jfieldID jnInt; jfieldID jsString; jstring jsStr; jobject joCurObj; jmethodID jmId; jcStruct = (*jpcEnv)->FindClass(jpcEnv, "com/jni/jernymyjni"); JNI_ASSERT_P_RTN_VAR(jcStruct, NULL); jchChar = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "chChar", "C"); JNI_ASSERT_P_RTN_VAR(jchChar, NULL); jnInt = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "nInt", "I"); JNI_ASSERT_P_RTN_VAR(jnInt, NULL); #ifdef WIN32 jsString = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "sString", "Ljava/lang/String;"); #else jsString = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "sString", "Ljava/lang/String;"); // jsString = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "sString", "java/lang/String"); #endif JNI_ASSERT_P_RTN_VAR(jsString, NULL); // get class init method jmId = (*jpcEnv)->GetMethodID(jpcEnv, jcStruct, "<init>", "()V"); JNI_ASSERT_P_RTN_VAR(jsString, NULL); joCurObj = (*jpcEnv)->NewObject(jpcEnv, jcStruct, jmId); JNI_ASSERT_P_RTN_VAR(joCurObj, NULL); (*jpcEnv)->SetCharField(jpcEnv, joCurObj, jchChar, (char)(1+'d')); (*jpcEnv)->SetIntField(jpcEnv, joCurObj, jnInt, 0); sprintf(achBuf, "****sString[%d]%c", 0, 0); jsStr = (*jpcEnv)->NewStringUTF(jpcEnv, achBuf); JNI_ASSERT_P_RTN_VAR(jsStr, NULL); (*jpcEnv)->SetObjectField(jpcEnv, joCurObj, jsString, jsStr); printf("[C]-----%d, %c, %s/n", 0, 1+'0', achBuf); return joCurObj; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetClass (JNIEnv *jpcEnv, jobject jcObj, jobject jcSetStruct) { const char *lpcstrGet; jchar jchData; jint jnData; jobject jcObjStr; jfieldID jchChar; jfieldID jnInt; jfieldID jsString; jclass jcStruct; // here is the class name, java file create a com_jni_jernymyjni class, so name is jcStruct = (*jpcEnv)->FindClass(jpcEnv, "com/jni/jernymyjni"); JNI_ASSERT_P_RTN_VAR(jcStruct, JNI_ERR_NULL_CLASS); // char sig is "C", see the .h file, Signature: (C)[C jchChar = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "chChar", "C"); JNI_ASSERT_P_RTN_VAR(jchChar, JNI_ERR_NULL_CHAR); // int sig is "I", see the .h file, Signature: ([I[I)[I jnInt = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "nInt", "I"); JNI_ASSERT_P_RTN_VAR(jnInt, JNI_ERR_NULL_INT); // string, see the .h file, Signature: (Ljava/lang/String;)[Ljava/lang/String; jsString = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "sString", "Ljava/lang/String;"); JNI_ASSERT_P_RTN_VAR(jsString, JNI_ERR_NULL_STR); // get char field information jchData = (*jpcEnv)->GetCharField(jpcEnv, jcSetStruct, jchChar); printf("[C]-jchData:%c/n", jchData); // get int field information jnData = (*jpcEnv)->GetIntField(jpcEnv, jcSetStruct, jnInt); printf("[C]-jnData:%d/n", jnData); // get object field , now is string information jcObjStr = (*jpcEnv)->GetObjectField(jpcEnv, jcSetStruct, jsString); JNI_ASSERT_P_RTN_VAR(jcObjStr, JNI_ERR_NULL_FIELD_OBJ); // get const char information from jstring lpcstrGet = (*jpcEnv)->GetStringUTFChars(jpcEnv, (jstring)jcObjStr, 0); JNI_ASSERT_P_RTN_VAR(lpcstrGet, JNI_ERR_NULL_STR_UTF_C); printf("[C]-lpcstrGet:%s/n", lpcstrGet); // release const char information from jstring (*jpcEnv)->ReleaseStringUTFChars(jpcEnv, jcObjStr, lpcstrGet); printf("[C]-/n"); return 0; } #define STRUCT_ARRAY_NUM 3 JNIEXPORT jobjectArray JNICALL Java_com_jni_jernymyjni_GetClassArray (JNIEnv *jpcEnv, jobject jcObj) { int nIdx; char achBuf[32] = {0}; jclass jcStruct; jobjectArray jcAry; jfieldID jnInt; jfieldID jchChar; jfieldID jsString; jstring jsStr; jobject joCurObj; jmethodID jmId; // here is the class name, java file create a com_jni_jernymyjni class, so name is jcStruct = (*jpcEnv)->FindClass(jpcEnv, "com/jni/jernymyjni"); JNI_ASSERT_P_RTN_VAR(jcStruct, NULL); // how many array will create, now is 3, and init is 0; jcAry = (*jpcEnv)->NewObjectArray(jpcEnv, STRUCT_ARRAY_NUM, jcStruct, 0); JNI_ASSERT_P_RTN_VAR(jcAry, NULL); // char sig is "C", see the .h file, Signature: (C)[C jchChar = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "chChar", "C"); JNI_ASSERT_P_RTN_VAR(jchChar, NULL); // int sig is "I", see the .h file, Signature: ([I[I)[I jnInt = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "nInt", "I"); JNI_ASSERT_P_RTN_VAR(jnInt, NULL); // string, see the .h file, Signature: (Ljava/lang/String;)[Ljava/lang/String; jsString = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "sString", "Ljava/lang/String;"); JNI_ASSERT_P_RTN_VAR(jsString, NULL); // get class method, 得到类的构造函数 jmId = (*jpcEnv)->GetMethodID(jpcEnv, jcStruct, "<init>", "()V"); JNI_ASSERT_P_RTN_VAR(jmId, NULL); for (nIdx = 0; nIdx < STRUCT_ARRAY_NUM; nIdx++) { // create a new object area, like malloc or alloc buffer joCurObj = (*jpcEnv)->NewObject(jpcEnv, jcStruct, jmId); JNI_ASSERT_P_RTN_VAR(joCurObj, NULL); // set the char value (*jpcEnv)->SetCharField(jpcEnv, joCurObj, jchChar, (char)(nIdx+'a')); // set the int value (*jpcEnv)->SetIntField(jpcEnv, joCurObj, jnInt, nIdx); sprintf(achBuf, "****sString[%d]%c", nIdx, 0); // get jstring with achBuf jsStr = (*jpcEnv)->NewStringUTF(jpcEnv, achBuf); JNI_ASSERT_P_RTN_VAR(jsStr, NULL); // set the string value (*jpcEnv)->SetObjectField(jpcEnv, joCurObj, jsString, jsStr); printf("[C]-Line:%d-Java_com_jni_jernymyjni_GetClassArray/n", __LINE__); printf("[C]-----%d, %c, %s/n", nIdx, 'd', achBuf); // set all struct value with index (*jpcEnv)->SetObjectArrayElement(jpcEnv, jcAry, nIdx, joCurObj); } return jcAry; } JNIEXPORT jint JNICALL Java_com_jni_jernymyjni_SetClassArray (JNIEnv *jpcEnv, jobject jcObj, jobjectArray jcObjAry) { int nIdx; const char *lpcstrGet; jobject jcObjCur; jchar jchData; jint jnData; jobject jcObjStr; jfieldID jchChar; jfieldID jnInt; jfieldID jsString; jclass jcStruct; int nLen = (*jpcEnv)->GetArrayLength(jpcEnv, jcObjAry); // here is the class name, java file create a com_jni_jernymyjni class, so name is jcStruct = (*jpcEnv)->FindClass(jpcEnv, "com/jni/jernymyjni"); JNI_ASSERT_P_RTN_VAR(jcStruct, JNI_ERR_NULL_CLASS); // char sig is "C", see the .h file, Signature: (C)[C jchChar = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "chChar", "C"); // int sig is "I", see the .h file, Signature: ([I[I)[I jnInt = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "nInt", "I"); JNI_ASSERT_P_RTN_VAR(jnInt, JNI_ERR_NULL_INT); // string, see the .h file, Signature: (Ljava/lang/String;)[Ljava/lang/String; jsString = (*jpcEnv)->GetFieldID(jpcEnv, jcStruct, "sString", "Ljava/lang/String;"); JNI_ASSERT_P_RTN_VAR(jsString, JNI_ERR_NULL_STR); printf("[C]-jcObjAry length:%d/n", nLen); for (nIdx = 0; nIdx < nLen; nIdx++) { printf("[C]-index[%d]", nIdx); // get every object information jcObjCur = (*jpcEnv)->GetObjectArrayElement(jpcEnv, jcObjAry, nIdx); JNI_ASSERT_P_RTN_VAR(jcObjStr, JNI_ERR_NULL_OBJ_ARY_ELEMENT); // get char field information jchData = (*jpcEnv)->GetCharField(jpcEnv, jcObjCur, jchChar); // JNI_ASSERT_V_RTN_VAR(jchData, JNI_ERR_NULL_FIELD_CHAR); printf("[C]-jchData:%c/n", jchData); // get int field information jnData = (*jpcEnv)->GetIntField(jpcEnv, jcObjCur, jnInt); printf("[C]-jnData:%d/n", jnData); // get object field , now is string information jcObjStr = (*jpcEnv)->GetObjectField(jpcEnv, jcObjCur, jsString); JNI_ASSERT_P_RTN_VAR(jcObjStr, JNI_ERR_NULL_FIELD_OBJ); // get const char information from jstring lpcstrGet = (*jpcEnv)->GetStringUTFChars(jpcEnv, (jstring)jcObjStr, 0); JNI_ASSERT_P_RTN_VAR(lpcstrGet, JNI_ERR_NULL_STR_UTF_C); printf("[C]-lpcstrGet:%s/n", lpcstrGet); // release const char information from jstring (*jpcEnv)->ReleaseStringUTFChars(jpcEnv, jcObjStr, lpcstrGet); } printf("[C]-/n"); return 0; }

编写Android.mk，内容如下

# Android.mk by jernymy, 20110508 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := jernymyjni LOCAL_SRC_FILES := com_jni_jernymyjni.c include $(BUILD_SHARED_LIBRARY)

在VMware的ubuntu9.04下编译, NDK r4b的路径在../bld/android-ndk-r4-crystax，使用该ndkbuild

root@jernymy-desktop:/mnt/hgfs/workspace/AndroidJni# ../bld/android-ndk-r4-crystax/ndk-build
Compile thumb : jernymyjni <= /mnt/hgfs/workspace/AndroidJni/jni/com_jni_jernymyjni.c
SharedLibrary : libjernymyjni.so
Install : libjernymyjni.so => /mnt/hgfs/workspace/AndroidJni/libs/armeabi
root@jernymy-desktop:/mnt/hgfs/workspace/AndroidJni#

接下来编写我们的java的测试代码AndroidJni.java，目前为了方便调试，暂且用System.out输出，
可以通过android在界面上摆放一些button，然后把信息显示到button上，就可以看到效果了
现在可以先通过调试的方式，查看debug的信息。

package com.jni; import android.app.Activity; import android.os.Bundle; public class AndroidJni extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); System.out.println("hello"); jernymyjni cJni = new jernymyjni(); System.out.println("--------jernymy test jernymyjni start--------"); System.out.println("--------display base type test"); System.out.println("--------GetChar('A')--------"); char chTmp = cJni.GetChar('A'); System.out.println(String.valueOf(chTmp)); System.out.println("***************************"); System.out.println("--------SetChar('A')--------"); int nRtn = cJni.SetChar('A'); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("--------GetInt(5, 10)--------"); int nSum = cJni.GetInt(5, 10); System.out.println(String.valueOf(nSum)); System.out.println("***************************"); System.out.println("--------SetInt(10)--------"); nRtn = cJni.SetInt(10); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("--------GetStr(/"Jernymy Jni GetStr/")--------"); String sStr = cJni.GetStr(); System.out.println(sStr); System.out.println("***************************"); System.out.println("--------GetStr(/"Jernymy Jni PrcsStr/")--------"); sStr = cJni.PrcsStr("Jernymy Jni TestAAA"); System.out.println(sStr); System.out.println("***************************"); System.out.println("--------SetStr(/"Jernymy Jni SetStr/")--------"); nRtn = cJni.SetStr("Java Jni Set"); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("------------------------------------------------"); System.out.println("--------display array test"); System.out.println("--------GetCharArray('A')--------"); char[] chAry = cJni.GetCharArray('A'); int nIdx; System.out.println("chAry.length:" + String.valueOf(chAry.length)); for (nIdx = 0; nIdx < chAry.length; nIdx++) { System.out.println(String.valueOf(chAry[nIdx])+" "); } System.out.println("***************************"); System.out.println("--------SetCharArray('A')--------"); nRtn = cJni.SetCharArray(chAry); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("--------GetIntArray({1, 2, 3}, {4, 5, 6})--------"); int[] nAddAry1 = {1, 2, 3}; int[] nAddAry2 = {4, 5, 6}; int[] nSumAry = cJni.GetIntArray(nAddAry1, nAddAry2); System.out.println("nSumAry.length:" + String.valueOf(nSumAry.length)); for (nIdx = 0; nIdx < nSumAry.length; nIdx++) { System.out.println(String.valueOf(nSumAry[nIdx])+" "); } System.out.println("***************************"); System.out.println("--------SetIntArray({1, 2, 3}--------"); nRtn = cJni.SetIntArray(nAddAry1); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("--------GetStrArray(" + "/"Jernymy Java Jni GetStrArray/")--------"); String[] sStrAry = cJni.GetStrArray(); System.out.println("sStrAry.length:" + String.valueOf(sStrAry.length)); for (nIdx = 0; nIdx < sStrAry.length; nIdx++) { System.out.println(sStrAry[nIdx]+" "); } System.out.println("***************************"); System.out.println("--------PrcsStrArray(" + "/"Jernymy Java Jni PrcsStrArray/")--------"); sStrAry = cJni.PrcsStrArray("Jernymy Android JniTest"); System.out.println("sStrAry.length:" + String.valueOf(sStrAry.length)); for (nIdx = 0; nIdx < sStrAry.length; nIdx++) { System.out.println(sStrAry[nIdx]+" "); } System.out.println("***************************"); System.out.println("--------SetStrArray({/"Jernymy/"," + " /"Java/", /"Jni/", /"SetStrArray/"})--------"); String[] sStrSetAry = {"Jernymy", "Java", "Jni", "SetStrArray"}; nRtn = cJni.SetStrArray(sStrSetAry); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("-------------------------------------------------"); System.out.println("--------display class test"); System.out.println("--------GetClass(0)--------"); jernymyjni cComn = cJni.GetClass(0); if (null == cComn) { System.out.println("cComn is null"); } else { System.out.println( "chChar:" + String.valueOf(cComn.chChar) +" nPuId:" + String.valueOf(cComn.nInt) +" sName:" + cComn.sString); } System.out.println("***************************"); System.out.println("--------SetClass({'N', 508, /"Native/"})--------"); jernymyjni cComnSet = new jernymyjni(); cComnSet.chChar = 'N'; cComnSet.nInt = 508; cComnSet.sString = "Native"; nRtn = cJni.SetClass(cComnSet); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("--------GetClassArray()--------"); jernymyjni[] sStructAry = cJni.GetClassArray(); System.out.println("sStructAry:" + String.valueOf(sStructAry.length)); for (nIdx = 0; nIdx < sStructAry.length; nIdx++) { System.out.println("----index[" + String.valueOf(nIdx) + "]----"); if (null == sStructAry[nIdx]) { System.out.println("sStructAry is null"); } else { System.out.println("" +" chChar: " + String.valueOf(sStructAry[nIdx].chChar) +", nInt: " + String.valueOf(sStructAry[nIdx].nInt) +", sName: " + sStructAry[nIdx].sString); } } System.out.println("***************************"); System.out.println("--------SetClassArray(Ncomn[])--------"); System.out.println("sStructAry:" + String.valueOf(sStructAry.length)); for (nIdx = 0; nIdx < sStructAry.length; nIdx++) { System.out.println("index[" + String.valueOf(nIdx) +"] chChar:" + String.valueOf(sStructAry[nIdx].chChar) +" nInt:" + String.valueOf(sStructAry[nIdx].nInt) +" sString:" + sStructAry[nIdx].sString); } nRtn = cJni.SetClassArray(sStructAry); System.out.println("nRtn:" + String.valueOf(nRtn)); System.out.println("***************************"); System.out.println("--------Jernymy test jernymyjni end --------"); } }

好了，基本差不多了，因为俺暂时使用的类型已经足够了，至于其他的在继续研究中，如果错误的地方也请您指出，谢谢啦。
jernymy 20110508
jernymy@163.com

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