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How to convert char* to jcharArray in JNI

How can I convert char* to jcharArray in JNI?

What code do I have to put in // TODO comment part?

JNIEXPORT jcharArray JNICALL Java_finger_FingerPrintJNI_GetVer(JNIEnv *env, jobject thisObj){
    char* version = getText(); // Returns char* data type
    int version_len = strlen(version);

    jcharArray j_version_array = env->NewCharArray(version_len + 1);

    // TODO Convert char* to jcharArray

    return jcharArray;
}

Add ======================================================================

As Gearon suggested, when I put the below code an error is raised.

jchar* jVersion = (jchar*)version;
env->SetCharArrayRegion(jcharArray, 0, version_len, jVersion);

Following is the error message.

JNIEnv_::SetCharArrayRegion(jcharArray,jsize,jsize,const jchar *)': cannot convert argument 1 from 'jchar *' to 'jcharArray'
sample.cpp(26): note: Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
like image 719
Anderson Avatar asked Jul 21 '16 00:07

Anderson


2 Answers

Thanks for the code Gearon suggested my final code is something like this.

jchar* j_version = (jchar*)calloc(sizeof(jchar), version_len);
for(int i=0; i <= version_len; i++){
    j_version[i] =  (jchar) version[i];
}

jcharArray j_version_array = env->NewCharArray(version_len + 1);
env->SetCharArrayRegion(j_version_array, 0, version_len , j_version);
like image 133
Anderson Avatar answered Sep 30 '22 14:09

Anderson


You can use

jchar* jVersion = (jchar*)version;
env->SetCharArrayRegion(j_version_array, 0, version_len, jVersion);

Hope it can help you. Thanks.

like image 41
Eugene Avatar answered Sep 30 '22 15:09

Eugene