NativeActivity通过jni调用java层的Android APIjavasyliao的专栏-

1. 继承Nativity，打通native和java层

 public class MyNativeActivity extends NativeActivity {     @Override     public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);     Log.v("test","oncreate");     }       public void LoadWebSite(String url){     Log.v("test", "GetWebPicture, url is:" + url);     }  }

2. 修改AndroidManifest，让他启动你继承后的MyNativeActivity，而不是原生的NativeActivity 。

 把   activity android:name="android.app.NativeActivity"  改成 activity android:name=".MyNativeActivity"

这样，程序启动后运行java层的onCreate，其中super.onCreate(savedInstanceState)会调用到native层的void android_main(struct android_app* state) 入口。

3. 在native code中调用java函数

 void getWebPicture(struct android_app* app) {     jobject activityInstance = g_app->activity->clazz;     JavaVM* jvm = g_app->activity->vm;     JNIEnv *env = NULL;     (*jvm)->GetEnv(jvm, (void **) &env, JNI_VERSION_1_6);      if ((*jvm)->AttachCurrentThread(jvm, &env, NULL) < 0)     {     LOGE("callback_handler: failed to attach current thread");     return;     }      jclass clazz = (*env)->GetObjectClass(env, activityInstance);     if (!clazz) {     LOGE("callback_handler: failed to get WebPicCls class reference");      (*jvm)->DetachCurrentThread(app->activity->vm);     return;     }      jmethodID methodID = (*env)->GetMethodID(env, clazz, "LoadWebSite", "(Ljava/lang/String;)V");     if (!methodID) {     LOGE("callback_handler: failed to get LoadWebSite method ID");     (*jvm)->DetachCurrentThread(app->activity->vm);    return;     }      jstring url= (*env)->NewStringUTF(env, "https://198.168.1.104");     (*env)->CallVoidMethod(env, activityInstance, methodID, url);     (*env)->ReleaseStringUTFChars(env,url,(*env)->GetStringUTFChars(env, url, 0));     (*jvm)->DetachCurrentThread(jvm);  }