Android Java passes string type data to C

This article then implements the "Android Java pass int type data to C" method is still not implemented:

Public native string Sayhelloinc (string s);

First put a tool method, the specific meaning of the following article will be introduced

/** * Convert a jstring to a C language char* type.*/Char* _JSTRING2CSTR (jnienv*env, jstring jstr) {    Char* Rtn =NULL; Jclass clsstring= (*env)->findclass (env,"java/lang/string"); Jstring Strencode= (*env)->newstringutf (env,"GB2312"); Jmethodid Mid= (*env)->getmethodid (env, clsstring,"getBytes",            "(ljava/lang/string;) [B"); Jbytearray Barr= (Jbytearray) (*env),Callobjectmethod (env, JSTR, Mid, strencode);//String. GetByte ("GB2312");Jsize alen = (*env)Getarraylength (env, Barr); Jbyte* ba = (*env)getbytearrayelements (env, Barr, Jni_false); if(Alen >0) {Rtn= (Char*)malloc(Alen +1);//" the"memcpy (RTN, BA, Alen); Rtn[alen]=0; }    (*ENV)->releasebytearrayelements (env, Barr, BA,0); returnRtn;}

Then complete the Sayhelloinc function

/** Class:com_wuyudong_javapassdata_jni * method:sayhelloinc * Signature: (ljava/lang/string;) Ljava/lang/strin G */
jniexport jstring jnicall java_com_wuyudong_javapassdata_jni_sayhelloinc (jnienv*env, Jobject clazz, jstring jstr) {    //invoking a tool method converts a string type in Java into a charx in the C language    Char* CStr =_jstring2cstr (env, JSTR); intLen =strlen (CStr); inti;  for(i =0; i < Len; i++) {        * (CStr + i) + =1; }    return(*env)Newstringutf (env, CStr);}

Add the following code to the Mainactivity.java:

     Public void passstring (View v) {        toast.maketext (Getapplicationcontext (), Jni.sayhelloinc ("Hello Yudong"), 0). Show ();    }

Done, run the project.

Android Java passes string type data to C