Question:

How do I convert between Java strings and Unicode descriptors?

Answer:

To get a TPtrC from a Java string (received in a JNI context as a jstring), you can use the following code:

{code}
JNIEXPORT jint JNICALL Java_Example__1native(JNIEnv* aJNI, jclass, jstring aString)

{
const jchar* const ptr = aJNI->GetStringChars(aString, NULL);
const jsize len = aJNI->GetStringLength(aString);
TPtrC16 ptr16(ptr, len);
jint error = NativeStuff(ptr16); // must not modify data!
aJNI->ReleaseStringChars(aString, ptr); // original data no longer needed
return error;
}

{code}

TPtrC16 buf;
...
jstring str = aJNI->NewString(buf.Ptr(), buf.Length());

{code}

HBufC16* buf;
...
jstring str = aJNI->NewString(buf->Ptr(), buf->Length());