03

#include "com_example_ndkcallback_DataProvider.h"

 

/**

 * 调用：DataProvider中的 public void helloFromJava();

 */

JNIEXPORT void JNICALL Java_com_example_ndkcallback_DataProvider_callMethod1

  (JNIEnv *env, jobject jobject) {

    /**

     * Class<?> forName = Class.forName("com.example.ndkcallback.DataProvider");

     * Method declaredMethod = forName.getDeclaredMethod("helloFromJava", new Class[]{});

     * declaredMethod.invoke(forName.newInstance(), new Object[]{});

     */

         //jclass      (*FindClass)(JNIEnv*, const char*);

    jclass clazz = (*env)->FindClass(env,"com/example/ndkcallback/DataProvider");

    //jmethodID (*GetMethodID)(JNIEnv*,jclass,const char*,const char*)

    //方法签名   参数和返回值

    //GetMethodID中参数分别是env指针，class，方法名，方法签名

    jmethodID methodId=(*env)->GetMethodID(env,clazz,"helloFromJava","()V");

    //通过 void        (*CallVoidMethod)(JNIEnv*, jobject, jmethodID, ...);来调用Java的代码

    (*env)->CallVoidMethod(env,jobject,methodId);

}

 

/**

 * 调用：DataProvider中的 public int Add(int, int);

 */

JNIEXPORT void JNICALL Java_com_example_ndkcallback_DataProvider_callMethod2

  (JNIEnv *env, jobject jobject) {

         jclass clazz=(*env)->FindClass(env,"com/example/ndkcallback/DataProvider");

         //这里的方法签名中有几个I表示有几个参数

         jmethodID methodId=(*env)->GetMethodID(env,clazz,"Add","(II)I");

         // jint        (*CallIntMethod)(JNIEnv*, jobject, jmethodID, ...);

         (*env)->CallIntMethod(env,jobject,methodId,3,5);

}

 

/**

 * 调用：DataProvider中的 public void printString(java.lang.String);

 */

JNIEXPORT void JNICALL Java_com_example_ndkcallback_DataProvider_callMethod3

  (JNIEnv *env, jobject jobject) { // 参数 object  就是native方法所在的类

         jclass clazz=(*env)->FindClass(env,"com/example/ndkcallback/DataProvider");

         jmethodID methodId=(*env)->GetMethodID(env,clazz,"printString","(Ljava/lang/String;)V");

         // jint        (*CallIntMethod)(JNIEnv*, jobject, jmethodID, ...);

         jstring str=(*env)->NewStringUTF(env,"hello");

 

         (*env)->CallVoidMethod(env,jobject,methodId,str);

}

 

JNIEXPORT void JNICALL Java_com_example_ndkcallback_DataProvider_callMethod4

  (JNIEnv * env, jobject j){

         jclass clazz=(*env)->FindClass(env,"com/example/ndkcallback/MainActivity");

         //  jmethodID   (*GetMethodID)(JNIEnv*, jclass, const char*, const char*);

         // 方法签名  参数和返回值

         jmethodID methodId=(*env)->GetMethodID(env,clazz,"helloFromJava","()V");

         // void        (*CallVoidMethod)(JNIEnv*, jobject, jmethodID, ...);

         // 需要创建DataProvider的 对象

         // jobject     (*AllocObject)(JNIEnv*, jclass);

         jobject obj=(*env)->AllocObject(env,clazz);  // new MainActivity();

         (*env)->CallVoidMethod(env,obj,methodId);

 

}

 

JNIEXPORT void JNICALL Java_com_example_ndkcallback_DataProvider_callMethod5

  (JNIEnv * env, jobject j){

         jclass clazz=(*env)->FindClass(env,"com/example/ndkcallback/DataProvider");

         //     jmethodID   (*GetStaticMethodID)(JNIEnv*, jclass, const char*, const char*);

          jmethodID  methodid=(*env)->GetStaticMethodID(env,clazz,"demo","()V");

         //void        (*CallStaticVoidMethod)(JNIEnv*, jclass, jmethodID, ...);

          (*env)->CallStaticVoidMethod(env,clazz,methodid);

}