Solved Qt versus Android Java

[mrdebug]

Hi. I need to pass a char array to a java method.
Which is the right way?
This id the Java method:

public static int Write(char[] data, int maxSize)

and this is my cpp line of code (that does not work)

const char *data, int maxSize;
jint Result= QAndroidJniObject::callStaticMethod<jint>("it/labcsp/rfportal/rfportaltouch/BluetoothWrapper", "Write", "([CI)I", data, maxSize);

[raven-worx]

@mrdebug
there is not direct conversion from C++ char* to Java char[]!
Actually in JNI an array always needs to be explicitly created (e.g. using env->NewObjectArray() etc....)

So it would be easier if you can change the Java method signature to take a String (if possible):

QString str(data);
jstring jStr = QAndroidJniObject::fromString(str).object<jstring>();
jint Result= QAndroidJniObject::callStaticMethod<jint>("it/labcsp/rfportal/rfportaltouch/BluetoothWrapper", "Write", "(Ljava/lang/String;I)I", jStr, maxSize);

Or use a byte[] instead:

jbyteArray jBuff = env->NewByteArray( length );
env->SetByteArrayRegion(jBuff, 0, length, (jbyte*)buff);

jint Result= QAndroidJniObject::callStaticMethod<jint>("it/labcsp/rfportal/rfportaltouch/BluetoothWrapper", "Write", "([BI)I", jBuff, maxSize);

env->DeleteLocalRef(jBuff); // IMPORTANT TO AVOID MEMORY LEAK!

[mrdebug]

It works perfectly!