如何从JNI将数组传递给Java方法

Question

I am trying to pass a int array from JNI to Java . When I pass single or multiple int value, it works but passing array is not working. Every time app crash and return the following error

Error

Invalid indirect reference 0x48609264 in decodeIndirectRef
Fatal signal 11 (SIGSEGV) at 0xdeadd00d....

JNI

jclass dataClass = env->FindClass("com/mypkg/project/DemoNative");
javaClassRef = (jclass) env->NewGlobalRef(dataClass);
javaMethodRef = env->GetMethodID(javaClassRef, "onDataReady", "([II)V");
jobject javaObjectRef = env->NewObject(javaClassRef, javaMethodRef);
jint array[2] = {1};
jintArray result;
result = env->NewIntArray(2);
env->SetIntArrayRegion(result,0,2,array);
env->CallVoidMethod(javaObjectRef, javaMethodRef,result,2);

Java

public void onDataReady(int[] array,int len){
}

Answer 1

The line

jobject javaObjectRef = env->NewObject(javaClassRef, javaMethodRef);

is definitely wrong. It tries to use the method ID for onDataReady() as a constructor.

You probably need

jmethodID javaDefaultConstructor = env->GetMethodID(javaClassRef, "<init>", "()V");
jobject javaObjectRef = env->NewObject(javaClassRef, javaDefaultConstructor);

Note that jmethodID is not a reference: you can find the ID once and use it from any thread and on any instance you like. It's just a number, constant at least for the lifetime of your application.