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C透过JNI 层调用Java的静态和非静态方法

 Dragon_chen 2016-10-19
#include "Provider.h"
#include <android/log.h>
extern JNIEnv* jniEnv;
jclass TestProvider;
jobject mTestProvider;
jmethodID getTime;
jmethodID sayHello;
int GetProviderInstance(jclass obj_class);
/**
 * 初始化 类、对象、方法
 */
int InitProvider() {
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "InitProvider Begin  1" );
    if(jniEnv == NULL) {
        return 0;
    }
    if(TestProvider == NULL) {
        TestProvider = (*jniEnv)->FindClass(jniEnv,"com/duicky/TestProvider");
        if(TestProvider == NULL){
            return -1;
        }
        __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "InitProvider Begin  2 ok" );
    }
    if (mTestProvider == NULL) {
        if (GetProviderInstance(TestProvider) != 1) {
            (*jniEnv)->DeleteLocalRef(jniEnv, TestProvider);
            return -1;
        }
        __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "InitProvider Begin  3 ok" );
    }
    if (getTime == NULL) {
        getTime = (*jniEnv)->GetStaticMethodID(jniEnv, TestProvider, "getTime","()Ljava/lang/String;");
        if (getTime == NULL) {
            (*jniEnv)->DeleteLocalRef(jniEnv, TestProvider);
            (*jniEnv)->DeleteLocalRef(jniEnv, mTestProvider);
            return -2;
        }
        __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "InitProvider Begin  4 ok" );
    }
    if (sayHello == NULL) {
        sayHello = (*jniEnv)->GetMethodID(jniEnv, TestProvider, "sayHello","(Ljava/lang/String;)V");
        if (sayHello == NULL) {
            (*jniEnv)->DeleteLocalRef(jniEnv, TestProvider);
            (*jniEnv)->DeleteLocalRef(jniEnv, mTestProvider);
            (*jniEnv)->DeleteLocalRef(jniEnv, getTime);
            return -3;
        }
        __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "InitProvider Begin  5 ok" );
    }
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "InitProvider Begin  6" );
    return 1;
}
int GetProviderInstance(jclass obj_class) {
    if(obj_class == NULL) {
        return 0;
    }
    jmethodID construction_id = (*jniEnv)->GetMethodID(jniEnv, obj_class,
            "<init>", "()V");
    if (construction_id == 0) {
        return -1;
    }
    mTestProvider = (*jniEnv)->NewObject(jniEnv, obj_class,
            construction_id);
    if (mTestProvider == NULL) {
        return -2;
    }
    return 1;
}
/**
 * 获取时间 ---- 调用 Java 方法
 */
void GetTime() {
    if(TestProvider == NULL || getTime == NULL) {
        int result = InitProvider();
        if (result != 1) {
            return;
        }
    }
    jstring jstr = NULL;
    char* cstr = NULL;
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "GetTime Begin" );
    jstr = (*jniEnv)->CallStaticObjectMethod(jniEnv, TestProvider, getTime);
    cstr = (char*) (*jniEnv)->GetStringUTFChars(jniEnv,jstr, 0);
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "Success Get Time from Java , Value = %s",cstr );
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "GetTime End" );
    (*jniEnv)->ReleaseStringUTFChars(jniEnv, jstr, cstr);
    (*jniEnv)->DeleteLocalRef(jniEnv, jstr);
}
/**
 * SayHello ---- 调用 Java 方法
 */
void SayHello() {
    if(TestProvider == NULL || mTestProvider == NULL || sayHello == NULL) {
        int result = InitProvider() ;
        if(result != 1) {
            return;
        }
    }
    jstring jstrMSG = NULL;
    jstrMSG =(*jniEnv)->NewStringUTF(jniEnv, "Hi,I'm From C");
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "SayHello Begin" );
    (*jniEnv)->CallVoidMethod(jniEnv, mTestProvider, sayHello,jstrMSG);
    __android_log_print(ANDROID_LOG_INFO, "JNIMsg", "SayHello End" );
    (*jniEnv)->DeleteLocalRef(jniEnv, jstrMSG);
}

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