【发布时间】：2012-12-20 05:22:18
【问题描述】：
我正在尝试从我的 cpp 类调用我的 java 类中的一些函数。我成功地进行了三次这些调用，直到我第四次调用函数。我正在使用 cocos2dx 引擎。
我从 MiscManagerJni.cpp 调用 MiscManager.java 中的函数
当我尝试获取 classID 并且游戏崩溃时出现以下错误：
12-20 12:06:09.328: W/System.err(26651): java.lang.NoClassDefFoundError: [通用] 12-20 12:06:09.328: W/System.err(26651): at dalvik.system.NativeStart.main(Native Method) 12-20 08:56:35.402: D/libMiscManager(25952): 找不到 com/games/Game/MiscManager 的类
我已经从 MiscManagerJni.cpp 类中成功调用了 MiscManager.java 类中的函数 3 次。但是当我调用时，第 4 次返回 null
jclass ret = pEnv->FindClass(CLASS_NAME);
谁能告诉我是什么导致了这个错误。
这些是我用来获取方法 id 和类 id 的函数
#define LOG_TAG "libMiscManager"
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)
#define CLASS_NAME "com/games/Game/MiscManager"
typedef struct JniMethodInfo_
{
JNIEnv * env;
jclass classID;
jmethodID methodID;
} JniMethodInfo;
extern "C"
{
// get env and cache it
static JNIEnv* getJNIEnv(void)
{
JavaVM* jvm = cocos2d::JniHelper::getJavaVM();
if (NULL == jvm) {
LOGD("Failed to get JNIEnv. JniHelper::getJavaVM() is NULL");
return NULL;
}
JNIEnv *env = NULL;
// get jni environment
jint ret = jvm->GetEnv((void**)&env, JNI_VERSION_1_4);
switch (ret) {
case JNI_OK :
// Success!
return env;
case JNI_EDETACHED :
// Thread not attached
if (jvm->AttachCurrentThread(&env, NULL) < 0)
{
LOGD("Failed to get the environment using AttachCurrentThread()");
return NULL;
} else {
// Success : Attached and obtained JNIEnv!
return env;
}
case JNI_EVERSION :
// Cannot recover from this error
LOGD("JNI interface version 1.4 not supported");
default :
LOGD("Failed to get the environment using GetEnv()");
return NULL;
}
}
// get class and make it a global reference, release it at endJni().
static jclass getClassID(JNIEnv *pEnv)
{
jclass ret = pEnv->FindClass(CLASS_NAME);
if (! ret)
{
LOGD("Failed to find class of %s", CLASS_NAME);
}
return ret;
}
static bool getStaticMethodInfo(cocos2d::JniMethodInfo &methodinfo, const char *methodName, const char *paramCode)
{
jmethodID methodID = 0;
JNIEnv *pEnv = 0;
bool bRet = false;
do
{
pEnv = getJNIEnv();
if (! pEnv)
{
break;
}
jclass classID = getClassID(pEnv);
methodID = pEnv->GetStaticMethodID(classID, methodName, paramCode);
if (! methodID)
{
LOGD("Failed to find static method id of %s", methodName);
break;
}
methodinfo.classID = classID;
methodinfo.env = pEnv;
methodinfo.methodID = methodID;
bRet = true;
} while (0);
return bRet;
}
void InitJni()
{
cocos2d::JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "Init", "()V"))
{
return ;
}
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
void SaveBooleanJni(const char *key, bool value)
{
cocos2d::JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "SaveBoolean", "(Ljava/lang/String;Z)V"))
{
return;
}
jstring stringArg = methodInfo.env->NewStringUTF(key);
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID, stringArg, value);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
void SaveIntegerJni(const char *key, int value)
{
cocos2d::JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "SaveInteger", "(Ljava/lang/String;I)V"))
{
return;
}
jstring stringArg = methodInfo.env->NewStringUTF(key);
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID, stringArg, value);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
void SaveLongJni(const char *key, long value)
{
cocos2d::JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "SaveLong", "(Ljava/lang/String;J)V"))
{
return;
}
jstring stringArg = methodInfo.env->NewStringUTF(key);
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID, stringArg, value);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
long GetLongJni(const char *key, long defaultValue)
{
cocos2d::JniMethodInfo methodInfo;
long ret = 0;
if (! getStaticMethodInfo(methodInfo, "GetInteger", "(Ljava/lang/String;J)J"))
{
return ret;
}
jstring stringArg = methodInfo.env->NewStringUTF(key);
ret = methodInfo.env->CallStaticLongMethod(methodInfo.classID, methodInfo.methodID, stringArg, defaultValue);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
return (long)ret;
}
bool GetBooleanJni(const char *key, bool defaultValue)
{
cocos2d::JniMethodInfo methodInfo;
jboolean ret = false;
if (! getStaticMethodInfo(methodInfo, "GetBoolean", "(Ljava/lang/String;Z)Z"))
{
return ret;
}
jstring stringArg = methodInfo.env->NewStringUTF(key);
ret = methodInfo.env->CallStaticIntMethod(methodInfo.classID, methodInfo.methodID, stringArg, defaultValue);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
return ret;
}
int GetIntegerJni(const char *key, int defaultValue)
{
cocos2d::JniMethodInfo methodInfo;
int ret = 0;
if (! getStaticMethodInfo(methodInfo, "GetInteger", "(Ljava/lang/String;I)I"))
{
return ret;
}
jstring stringArg = methodInfo.env->NewStringUTF(key);
ret = methodInfo.env->CallStaticIntMethod(methodInfo.classID, methodInfo.methodID, stringArg, defaultValue);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
return (unsigned int)ret;
}
bool IsConnectedToNetworkJni()
{
cocos2d::JniMethodInfo methodInfo;
jboolean ret = false;
if (! getStaticMethodInfo(methodInfo, "IsConnectedToNetwork", "()Z"))
{
return ret;
}
ret = methodInfo.env->CallStaticBooleanMethod(methodInfo.classID, methodInfo.methodID);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
return ret;
}
}
【问题讨论】：
-
getStaticMethodInfo(methodInfo, "SaveLong", "(Ljava/lang/String;J)V") : com/games/Game/MiscManager 参考在哪里？对我来说，似乎缺少一个参数类名。
-
对不起，我已经添加了其余的函数，你可以看到我已经定义了类名
-
你能展示适用于其他调用的代码吗？它在找不到类时失败似乎很奇怪，而我们预计找不到方法或其他问题......
-
我已经在 jni 类中添加了所有其他功能
-
也许 java 类没有在 pkg 中更新或者在缓存中所以它不包含新的 SaveLong 方法？
标签： java android c++ java-native-interface cocos2d-x