我正在尝试在我的 Android 应用程序中使用 JNI 代码。我经常调用 native 方法,该方法返回 jfloatArray:
JNIEXPORT jfloatArray JNICALL Java_com_qualcomm_QCARSamples_ImageTargets_DetectionBasedTracker_getvaluenative
(JNIEnv *env, jclass, jlong thiz,jfloatArray feature)
{ // these are my variables
CvMat* cameraMat = cvCreateMat(3,3,CV_32F);
CvMat* distMat =cvCreateMat(4,1,CV_32F);
jfloat* flt1 = env->GetFloatArrayElements(feature,0);
CvMat* imageMat = cvCreateMat(5,2,CV_32F);
CvMat* objMat = cvCreateMat(5,3,CV_32F);
CvMat* vec1 = cvCreateMat(1,3,CV_32F);
CvMat* vec2 = cvCreateMat(1,3,CV_32F);
Mat rotM ;
Mat m(vec1);
Mat t(vec2);
Mat rotM1 = rotM.t();
CvMat n = rotM1;
CvMat translat= t;
jfloatArray resultArray = env->NewFloatArray(12 );
float matrice[12];
env->SetFloatArrayRegion(resultArray, 0,12 ,matrice);
操作这些变量后,我像这样释放它们:
cvReleaseMat(&vec1);
cvReleaseMat(&vec2);
cvReleaseMat(&distMat);
cvReleaseMat(&cameraMat);
cvReleaseMat(&imageMat);
cvReleaseMat(&objMat);
rotM.release();
rotM1.release();
m.release();
t.release();
env->ReleaseFloatArrayElements(feature, flt1, 0);
env->DeleteLocalRef(feature);
return resultArray;
}
我的应用程序崩溃了,我的 Logcat 中有此内容:
05-02 13:41:03.179: W/dalvikvm(11288): ReferenceTable overflow (max=1024)
05-02 13:41:03.179: W/dalvikvm(11288): JNI pinned array reference table (0x32e248) dump:
05-02 13:41:03.179: W/dalvikvm(11288): Last 10 entries (of 1024):
05-02 13:41:03.179: W/dalvikvm(11288): 1023: 0x4105ad68 float[] (10 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1022: 0x4106d220 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1021: 0x41071db0 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1020: 0x4106d610 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1019: 0x4106d508 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1018: 0x4106efb0 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1017: 0x41072698 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1016: 0x410870c8 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1015: 0x4106cb88 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1014: 0x41087268 float[] (12 elements)
05-02 13:41:03.179: W/dalvikvm(11288): Summary:
05-02 13:41:03.179: W/dalvikvm(11288): 1 of float[] (10 elements)
05-02 13:41:03.179: W/dalvikvm(11288): 1023 of float[] (12 elements) (1023 unique instances)
05-02 13:41:03.179: E/dalvikvm(11288): Failed adding to JNI pinned array ref table (1024 entries)
你知道为什么会发生溢出吗?我做错了什么?
最佳答案
如果您保留对返回 float 组的引用,它们将不会被删除,并且您将达到 JNI 本地引用的限制。
来自评论中的其他方法:
param= (env->GetFloatArrayElements(imageArray,0));
then i have release it : env->DeleteLocalRef(imageArray);
您必须使用 ReleaseFloatArrayElements
释放参数,而不是使用 DeleteLocalRef
:
env->ReleaseFloatArrayElements(imageArray, param, 0);
此外,除非您也在 Java 中进行一些处理,否则您应该只在 native 代码中进行所有处理,而无需在 Java 和 native 代码之间来回切换。在您的设计中,似乎您在 native 代码中创建并填充了一个数组,然后将其返回到 Java,仅将其传递回另一个 native 方法。除非有充分的理由这样做,否则您可以在 native 代码中完成所有必需的处理,然后返回结果。
关于c++ - 引用表溢出(最大值=1024),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16360634/