android jni代码回调java的问题

因为多线程原因会导致找不到java类，无法call函数的问题

问题1找不到java类

在JNI_OnLoad的时候 保存下来

JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void* reserved)

{

    g_vm = vm;

    JNIEnv* env = NULL;

    jint result = -1;

    if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {

        return -1;

    }

    assert(env != NULL);

    register_location_methods(env);

    result = JNI_VERSION_1_4;

    return result;

}

int register_location_methods(JNIEnv *env)

{

    jniEnv = env;

    jclass clazz;

    clazz = env->FindClass("com/TongBan/Chat/NetBilling");

    if (clazz == NULL) {

        return -1;

    }

    JNetBilling = clazz;

    onReceivedMsgType = env->GetStaticMethodID(clazz,

                    "OnReceivedMsgType", "(I)V");

//    env->CallStaticVoidMethod(JNetBilling, onReceivedMsgType, 1);

    return 0;

}

问题2多线程回调call函数

此处生成的JNIEnv无法获取到class 函数 等 须要之前保存好的全局变量

bool isAttacked = false;

    JNIEnv* env;

    int status = g_vm->GetEnv((void **) &env, JNI_VERSION_1_4);

    if (status < 0) {

        status = g_vm->AttachCurrentThread(&env, NULL);

        if (status < 0) {

            return len;

        }

        isAttacked = true;

    }

    env->CallStaticVoidMethod(JNetBilling,onReceivedMsgType,iMsgType);

    if (isAttacked) {

        g_vm->DetachCurrentThread();

    }

输出问题因为还是比較喜欢cout就百度了个cout输出到logCat日志的

int iMsgType = MSG_PACKET::GetMsgType(kBuffer);

    StreamBuf g_StreamBuf;

    std::cout.rdbuf(&g_StreamBuf);

    std::cout << iMsgType;//就可以显示到logCat

#include <iostream>

#include <streambuf>

class StreamBuf : public std::streambuf

{

    enum

    {

        BUFFER_SIZE = 255,

    };

public:

    StreamBuf()

    {

        buffer_[BUFFER_SIZE] = '\0';

        setp(buffer_, buffer_ + BUFFER_SIZE - 1);

    }

    ~StreamBuf()

    {

        sync();

    }

protected:

    virtual int_type overflow(int_type c)

    {

        if (c != EOF)

        {

            *pptr() = c;

            pbump(1);

        }

        flush_buffer();

        return c;

    }

    virtual int sync()

    {

        flush_buffer();

        return 0;

    }

private:

    int flush_buffer()

    {

        int len = int(pptr() - pbase());

        if (len <= 0)

            return 0;

        if (len <= BUFFER_SIZE)

            buffer_[len] = '\0';

#ifdef ANDROID

        android_LogPriority t = ANDROID_LOG_INFO;

        __android_log_write(t, "JNI_DEBUG", buffer_);

#else

        printf("%s", buffer_);

#endif

        pbump(-len);

        return len;

    }

private:

    char buffer_[BUFFER_SIZE + 1];

};

到这里 最终能够 互动了 android->server->android