php - Android java.lang.NullPointerException: lock == null -
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- what nullpointerexception, , how fix it? 12 answers
i got following error. java.lang.nullpointerexception: lock == null while json file server.i googled cant find solution this. using wamp server, mysql , php connect database, when try register below error.
i have highlighted both of error on line 189 , 232 in block quotes. please me wrong these lines.
error log
-04 19:41:08.572 2414-2481/com.brad.visor e/buffer error﹕ error converting result java.lang.nullpointerexception: lock == null 07-04 19:41:08.572 2414-2481/com.brad.visor e/json parser﹕ error parsing data org.json.jsonexception: end of input @ character 0 of 07-04 19:41:08.602 2414-2414/com.brad.visor e/androidruntime﹕ fatal exception: main process: com.brad.visor, pid: 2414 java.lang.nullpointerexception: attempt invoke virtual method 'java.lang.string org.json.jsonobject.getstring(java.lang.string)' on null object reference @ com.brad.visor.register$processregister.onpostexecute(register.java:232) @ com.brad.visor.register$processregister.onpostexecute(register.java:189) @ android.os.asynctask.finish(asynctask.java:636) @ android.os.asynctask.access$500(asynctask.java:177) @ android.os.asynctask$internalhandler.handlemessage(asynctask.java:653) @ android.os.handler.dispatchmessage(handler.java:102) @ android.os.looper.loop(looper.java:135) @ android.app.activitythread.main(activitythread.java:5257) @ java.lang.reflect.method.invoke(native method) @ java.lang.reflect.method.invoke(method.java:372) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:903) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:698) register.java file
public class register extends activity { /** * json response node names. **/ private static string key_success = "success"; private static string key_uid = "uid"; private static string key_firstname = "fname"; private static string key_lastname = "lname"; private static string key_username = "uname"; private static string key_email = "email"; private static string key_created_at = "created_at"; private static string key_error = "error"; /** * defining layout items. **/ edittext inputfirstname; edittext inputlastname; edittext inputusername; edittext inputemail; edittext inputpassword; button btnregister; textview registererrormsg; /** * called when activity first created. */ @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.register); /** * defining layout items **/ inputfirstname = (edittext) findviewbyid(r.id.fname); inputlastname = (edittext) findviewbyid(r.id.lname); inputusername = (edittext) findviewbyid(r.id.uname); inputemail = (edittext) findviewbyid(r.id.email); inputpassword = (edittext) findviewbyid(r.id.pword); btnregister = (button) findviewbyid(r.id.register); registererrormsg = (textview) findviewbyid(r.id.register_error); /** * button switches login screen on clicked **/ button login = (button) findviewbyid(r.id.bktologin); login.setonclicklistener(new view.onclicklistener() { public void onclick(view view) { intent myintent = new intent(view.getcontext(), login.class); startactivityforresult(myintent, 0); finish(); } }); /** * register button click event. * toast set alert when fields empty. * toast set alert username must 5 characters. **/ btnregister.setonclicklistener(new view.onclicklistener() { @override public void onclick(view view) { if ( ( !inputusername.gettext().tostring().equals("")) && ( !inputpassword.gettext().tostring().equals("")) && ( !inputfirstname.gettext().tostring().equals("")) && ( !inputlastname.gettext().tostring().equals("")) && ( !inputemail.gettext().tostring().equals("")) ) { if ( inputusername.gettext().tostring().length() > 4 ){ netasync(view); } else { toast.maketext(getapplicationcontext(), "username should minimum 5 characters", toast.length_short).show(); } } else { toast.maketext(getapplicationcontext(), "one or more fields empty", toast.length_short).show(); } } }); } /** * async task check whether internet connection working **/ private class netcheck extends asynctask<string,string,boolean> { private progressdialog ndialog; @override protected void onpreexecute(){ super.onpreexecute(); ndialog = new progressdialog(register.this); ndialog.setmessage("loading.."); ndialog.settitle("checking network"); ndialog.setindeterminate(false); ndialog.setcancelable(true); ndialog.show(); } @override protected boolean doinbackground(string... args){ /** * gets current device state , checks working internet connection trying google. **/ connectivitymanager cm = (connectivitymanager) getsystemservice(context.connectivity_service); networkinfo netinfo = cm.getactivenetworkinfo(); if (netinfo != null && netinfo.isconnected()) { try { url url = new url("http://www.google.com"); httpurlconnection urlc = (httpurlconnection) url.openconnection(); urlc.setconnecttimeout(3000); urlc.connect(); if (urlc.getresponsecode() == 200) { return true; } } catch (malformedurlexception e1) { // todo auto-generated catch block e1.printstacktrace(); } catch (ioexception e) { // todo auto-generated catch block e.printstacktrace(); } } return false; } @override protected void onpostexecute(boolean th){ if(th == true){ ndialog.dismiss(); new processregister().execute(); } else{ ndialog.dismiss(); registererrormsg.settext("error in network connection"); } } } private class processregister extends asynctask<string, string, jsonobject> { // error here
/** * defining process dialog **/ private progressdialog pdialog; string email,password,fname,lname,uname; @override protected void onpreexecute() { super.onpreexecute(); inputusername = (edittext) findviewbyid(r.id.uname); inputpassword = (edittext) findviewbyid(r.id.pword); fname = inputfirstname.gettext().tostring(); lname = inputlastname.gettext().tostring(); email = inputemail.gettext().tostring(); uname= inputusername.gettext().tostring(); password = inputpassword.gettext().tostring(); pdialog = new progressdialog(register.this); pdialog.settitle("contacting servers"); pdialog.setmessage("registering ..."); pdialog.setindeterminate(false); pdialog.setcancelable(true); pdialog.show(); } @override protected jsonobject doinbackground(string... args) { userfunctions userfunction = new userfunctions(); jsonobject json = userfunction.registeruser(fname, lname, email, uname, password); return json; } @override protected void onpostexecute(jsonobject json) { /** * checks success message. **/ try { if (json.getstring(key_success) != null) { //error here
registererrormsg.settext(""); string res = json.getstring(key_success); string red = json.getstring(key_error); if(integer.parseint(res) == 1){ pdialog.settitle("getting data"); pdialog.setmessage("loading info"); registererrormsg.settext("successfully registered"); databasehandler db = new databasehandler(getapplicationcontext()); jsonobject json_user = json.getjsonobject("user"); /** * removes previous data in sqlite database **/ userfunctions logout = new userfunctions(); logout.logoutuser(getapplicationcontext()); db.adduser(json_user.getstring(key_firstname),json_user.getstring(key_lastname),json_user.getstring(key_email),json_user.getstring(key_username),json_user.getstring(key_uid),json_user.getstring(key_created_at)); /** * stores registered data in sqlite database * launch registered screen **/ intent registered = new intent(getapplicationcontext(), registered.class); /** * close views before launching registered screen **/ registered.addflags(intent.flag_activity_clear_top); pdialog.dismiss(); startactivity(registered); finish(); } else if (integer.parseint(red) ==2){ pdialog.dismiss(); registererrormsg.settext("user exists"); } else if (integer.parseint(red) ==3){ pdialog.dismiss(); registererrormsg.settext("invalid email id"); } } else{ pdialog.dismiss(); registererrormsg.settext("error occured in registration"); } } catch (jsonexception e) { e.printstacktrace(); } }} public void netasync(view view){ new netcheck().execute(); }} manifest.java file
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.brad.visor" > <application android:icon="@mipmap/logo" android:label="@string/app_name" android:theme="@style/apptheme" > <activity android:name=".mainactivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.main" /> <category android:name="android.intent.category.launcher" /> </intent-filter> </activity> <activity android:name=".login"> </activity> <activity android:name=".register"> </activity> <activity android:name=".registered"> </activity> <activity android:name=".main"> </activity> <activity android:name=".passwordreset"> </activity> <activity android:name=".changepassword"> </activity> </application> <!-- allow connect internet , know current network state--> <uses-permission android:name="android.permission.internet" /> <uses-permission android:name="android.permission.access_wifi_state" /> <uses-permission android:name="android.permission.access_network_state" /> </manifest> userfunction.java code
public class userfunctions { private jsonparser jsonparser; //url of php api private static string loginurl = "http://192.168.0.3:8080/bradvisor_login_api/"; private static string registerurl = "http://192.168.0.3:8080/bradvisor_login_api/"; private static string forpassurl = "http://192.168.0.3:8080/bradvisor_login_api/"; private static string chgpassurl = "http://192.168.0.3:8080/bradvisor_login_api/"; private static string login_tag = "login"; private static string register_tag = "register"; private static string forpass_tag = "forpass"; private static string chgpass_tag = "chgpass"; // constructor public userfunctions(){ jsonparser = new jsonparser(); } /** * function login **/ public jsonobject loginuser(string email, string password){ // building parameters list params = new arraylist(); params.add(new basicnamevaluepair("tag", login_tag)); params.add(new basicnamevaluepair("email", email)); params.add(new basicnamevaluepair("password", password)); jsonobject json = jsonparser.getjsonfromurl(loginurl, params); return json; } /** * function change password **/ public jsonobject chgpass(string newpas, string email){ list params = new arraylist(); params.add(new basicnamevaluepair("tag", chgpass_tag)); params.add(new basicnamevaluepair("newpas", newpas)); params.add(new basicnamevaluepair("email", email)); jsonobject json = jsonparser.getjsonfromurl(chgpassurl, params); return json; } /** * function reset password **/ public jsonobject forpass(string forgotpassword){ list params = new arraylist(); params.add(new basicnamevaluepair("tag", forpass_tag)); params.add(new basicnamevaluepair("forgotpassword", forgotpassword)); jsonobject json = jsonparser.getjsonfromurl(forpassurl, params); return json; } /** * function register **/ public jsonobject registeruser(string fname, string lname, string email, string uname, string password){ // building parameters list params = new arraylist(); params.add(new basicnamevaluepair("tag", register_tag)); params.add(new basicnamevaluepair("fname", fname)); params.add(new basicnamevaluepair("lname", lname)); params.add(new basicnamevaluepair("email", email)); params.add(new basicnamevaluepair("uname", uname)); params.add(new basicnamevaluepair("password", password)); jsonobject json = jsonparser.getjsonfromurl(registerurl,params); return json; } /** * function logout user * resets temporary data stored in sqlite database * */ public boolean logoutuser(context context){ databasehandler db = new databasehandler(context); db.resettables(); return true; } } jsonpraser.java file
public class jsonparser { static inputstream = null; static jsonobject jobj = null; static string json = ""; // constructor public jsonparser() { } public jsonobject getjsonfromurl(string url, list params) { // making http request try { // defaulthttpclient defaulthttpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(url); httppost.setentity(new urlencodedformentity(params)); httpresponse httpresponse = httpclient.execute(httppost); httpentity httpentity = httpresponse.getentity(); = httpentity.getcontent(); } catch (unsupportedencodingexception e) { e.printstacktrace(); } catch (clientprotocolexception e) { e.printstacktrace(); } catch (ioexception e) { e.printstacktrace(); } try { bufferedreader reader = new bufferedreader(new inputstreamreader( is, "iso-8859-1"), 8); stringbuilder sb = new stringbuilder(); string line = null; while ((line = reader.readline()) != null) { sb.append(line + "n"); } is.close(); json = sb.tostring(); log.e("json", json); } catch (exception e) { log.e("buffer error", "error converting result " + e.tostring()); } // try parse string json object try { jobj = new jsonobject(json); } catch (jsonexception e) { log.e("json parser", "error parsing data " + e.tostring()); } // return json string return jobj; }
the problem seems doinbackground returning null. thus, when onpostexecute runs, argument json null. avoid exception, test whether json null before proceeding rest of logic. you'll have find out why userfunction.registeruser(...) returning null fix problem.
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