JNI: Reading a text file in C code and returning to sdk

Question

Im trying to create an android app to read text from a text file using NDK .My C code reads a string into a variable and returns the string variable to java code .But when I

Answer 1

Try this:

JNIEXPORT jstring JNICALL Java_com_example_openfile_MainActivity_ndkopenfile
(JNIEnv *env, jobject this)
{
        char myStr[20];
        FILE* fp = fopen("/sdcard/x.txt","w+");
        if(fp!=NULL)
        {
            fgets(myStr,20,fp);
            fflush(fp);
            fclose(fp);
            return(*env)->NewStringUTF(env,myStr);
        }
        else
        {
            fclose(fp);
            return(*env)->NewStringUTF(env,"Error opening file!");
        }
}

This technique works perfectly !!! Tested.

Answer 2

I think your definition jstring str1[20]; need to modify to char str1[20]. Because jstring type is defined as a jobject, it's not basic type of char.