Question

如何将jni中的参数传递给java.in我的情况下我想将getUniqueTargetId传递给java（android）。谢谢您的帮助：） `class CloudImageTarget_UpdateCallback：public QCAR :: UpdateCallback {virtual void QCAR_onUpdate（QCAR :: State＆amp; state） {

        QCAR::TrackerManager& trackerManager = QCAR::TrackerManager::getInstance();

        QCAR::ImageTracker* imageTracker = static_cast<QCAR::ImageTracker*>(
                trackerManager.getTracker(QCAR::ImageTracker::getClassType()));

        QCAR::TargetFinder* finder = imageTracker->getTargetFinder();

        const int statusCode = finder->updateSearchResults();

        if (statusCode < 0)
        {
            showErrorMessage(statusCode, state.getFrame().getTimeStamp());
        }
        else if (statusCode == QCAR::TargetFinder::UPDATE_RESULTS_AVAILABLE)
        {
            // Process new search results
            if (finder->getResultCount() > 0)
            {
                const QCAR::TargetSearchResult* result = finder->getResult(0);

                if (result->getTrackingRating() > 0)
                {

                    QCAR::Trackable* newTrackable = finder->enableTracking(*result);
                    if (newTrackable != 0)
                    {
                        LOG("Successfully created new trackable '%s' with rating '%d'.",
                                newTrackable->getName(), result->getTrackingRating());


                        LOG( "Comparing Strings. currentTargetId: %s  lastTargetId: %s",
                                result->getUniqueTargetId(), lastTargetId);

                        if (strcmp(result->getUniqueTargetId(), lastTargetId) != 0)
                       {

                            renderState = RS_LOADING;

                            snprintf(targetMetadata, CONTENT_MAX, "%s",result->getMetaData());


                        }
                        else
                            renderState = RS_NORMAL;

                        pthread_mutex_lock(&framesToSkipMutex);
                        framesToSkipBeforeRenderingTransition = 10;
                        pthread_mutex_unlock(&framesToSkipMutex);
                        // Initialize state variables
                        trackingStarted = false;
                        // Updates the value of the current Target Id with the new target found
                        pthread_mutex_lock(&lastTargetIdMutex);
                        strcpy(lastTargetId, result->getUniqueTargetId());
                        pthread_mutex_unlock(&lastTargetIdMutex);
                        enterContentMode();
                    }
                    else
                        LOG("Failed to create new trackable.");
                }
            }
        }
    }

}; `

Answer 1

您可以使用反射调用JNI中的参数并将其传递给Java。

在Java类中创建一个方法

 void setUniqueTargetID(int targetID) {
     this.targetID = targetID;
 }

在你的JNI中动态获取课程

jclass clazz = (*env)->FindClass(env, "complete_package_name/class_name");

获取方法

jmethodID setUniqID= (*env)->GetMethodID(env, clazz, "setUniqueTargetID", "(I)");
(*env)->CallObjectMethod(env, obj, setUniqID, ID);

Answer 2

到目前为止我的代码： // inside virtual void QCAR_onUpdate（QCAR :: State＆amp; state）void我把这段代码： jclass cls = env->FindClass("com/qualcomm/QCARSamples/CloudImageTarget/CloudImageTarget"); jmethodID mid = env->GetMethodID(cls,"getUniqeTargetID", "([Ljava/lang/String;)V"); env->CallObjectMethod(jObj, mid,newTrackable->getName()); in java i create method String Msg; public void getUniqeTargetID(String msg) { this.Msg = msg; } \\in initApplicationAR i call the method: Log.d(TAG,"Target_Name: "+ Msg); log的结果：Target_Name：null .. 谢谢你的帮助Dayanand，请纠正我。谢谢你们。）

将参数从jni传递给java

2 个答案: