Android App - JSON - PHP - localhost --> NullPointerException by getting data from the php script -
i'm working on android app project , have got problem listview below code , logcat - errormessage; database stored @ localhost , using php script mysql database
main - activity of app
public class planactivity extends activity { string url = "http://10.0.2.2/phpbusplan/phpconnect.php"; inputstream is; arraylist<string> results = new arraylist<string>(); jsonobject json_data; @override protected void oncreate(bundle savedinstancestate) { // todo auto-generated method stub super.oncreate(savedinstancestate); setcontentview(r.layout.planlayout); radiogroup rgzeit = (radiogroup) findviewbyid(r.id.rgzeiten); } here data php script
public void getdata() { string result = ""; arraylist<namevaluepair> namevaluepairs = new arraylist<namevaluepair>(); // http post try{ httpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(url); httppost.setentity(new urlencodedformentity(namevaluepairs)); httpresponse response = httpclient.execute(httppost); httpentity entity = response.getentity(); = entity.getcontent(); }catch(exception e){ log.e("log_tag", "fehler bei der http verbindung "+e.tostring()); } // convert response string 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(); result=sb.tostring(); }catch(exception e){ log.e("log_tag", "error converting result "+e.tostring()); } // parse json data try{ jsonarray jarray = new jsonarray(result); for(int i=1;i<jarray.length();i++){ json_data = jarray.getjsonobject(i); results.add((string) json_data.get("idhaltestelle") + " "+ json_data.get("haltestellename")); } filllist(); } catch(jsonexception e){ log.e("log_tag", "error parsing data "+e.tostring()); } } public <t> void filllist() { listview liststart = (listview) findviewbyid(android.r.id.list); listadapter adapter = new arrayadapter<t>(getapplicationcontext(), android.r.layout.simple_list_item_1); liststart.setadapter(adapter);; }` log - cat message
10-07 17:43:39.557: e/androidruntime(702): fatal exception: main 10-07 17:43:39.557: e/androidruntime(702): java.lang.runtimeexception: unable start activity componentinfo{at.atn.android/at.atn.android.mainactivity}:java.lang.runtimeexception: unable start activity componentinfo{at.atn.android/at.atn.android.planactivity}: java.lang.nullpointerexception 10-07 17:43:39.557: e/androidruntime(702): at.android.app.activitythread.performlaunchactivity(activitythread.java:1647) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.handlelaunchactivity(activitythread.java:1663) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.access$1500(activitythread.java:117) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread$h.handlemessage(activitythread.java:931) 10-07 17:43:39.557: e/androidruntime(702): @ android.os.handler.dispatchmessage(handler.java:99) 10-07 17:43:39.557: e/androidruntime(702): @ android.os.looper.loop(looper.java:123) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.main(activitythread.java:3683) 10-07 17:43:39.557: e/androidruntime(702): @ java.lang.reflect.method.invokenative(native method) 10-07 17:43:39.557: e/androidruntime(702): @ java.lang.reflect.method.invoke(method.java:507) 10-07 17:43:39.557: e/androidruntime(702): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:839) 10-07 17:43:39.557: e/androidruntime(702): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:597) 10-07 17:43:39.557: e/androidruntime(702): @ dalvik.system.nativestart.main(native method) 10-07 17:43:39.557: e/androidruntime(702): caused by: java.lang.runtimeexception: unable start activity componentinfo{at.atn.android/at.atn.android.planactivity}: java.lang.nullpointerexception 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.performlaunchactivity(activitythread.java:1647) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.startactivitynow(activitythread.java:1487) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.localactivitymanager.movetostate(localactivitymanager.java:127) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.localactivitymanager.startactivity(localactivitymanager.java:339) 10-07 17:43:39.557: e/androidruntime(702): @ android.widget.tabhost$intentcontentstrategy.getcontentview(tabhost.java:654) 10-07 17:43:39.557: e/androidruntime(702): @ android.widget.tabhost.setcurrenttab(tabhost.java:326) 10-07 17:43:39.557: e/androidruntime(702): @ android.widget.tabhost.addtab(tabhost.java:216) 10-07 17:43:39.557: e/androidruntime(702): @ at.atn.android.mainactivity.oncreate(mainactivity.java:38) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1047) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.performlaunchactivity(activitythread.java:1611) 10-07 17:43:39.557: e/androidruntime(702): ... 11 more 10-07 17:43:39.557: e/androidruntime(702): caused by: java.lang.nullpointerexception 10-07 17:43:39.557: e/androidruntime(702): @ at.atn.android.planactivity.filllist(planactivity.java:143) 10-07 17:43:39.557: e/androidruntime(702): @ at.atn.android.planactivity.getdata(planactivity.java:132) 10-07 17:43:39.557: e/androidruntime(702): @ at.atn.android.planactivity.oncreate(planactivity.java:51) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1047) 10-07 17:43:39.557: e/androidruntime(702): @ android.app.activitythread.performlaunchactivity(activitythread.java:1611) 10-07 17:43:39.557: e/androidruntime(702): ... 20 more php - script ( name: phpconnect.php )
<?php $host = "localhost"; $username = "xxxxx"; $password = "xxxxx"; $db_name = "xxxxx"; mysql_connect($host,$username,$password); mysql_select_db($db_name); $q=mysql_query("select * haltestelle"); while($e=mysql_fetch_assoc($q)) $output[]=$e; print(json_encode($output)); mysql_close(); ?> json - data th php script
[{"idhaltestelle":"1","haltestellename":"schwarzenberg"},{"idhaltestelle":"2","haltestellename":"ulrichsberg"},{"idhaltestelle":"3","haltestellename":"aigen"},{"idhaltestelle":"4","haltestellename":"rohrbach"},{"idhaltestelle":"5","haltestellename":"st. owald"},{"idhaltestelle":"6","haltestellename":"st. stefan"},{"idhaltestelle":"7","haltestellename":"afiesl"},{"idhaltestelle":"8","haltestellename":"guglwald"},{"idhaltestelle":"9","haltestellename":"bad leonfelden"},{"idhaltestelle":"10","haltestellename":null},{"idhaltestelle":"11","haltestellename":"helfenberg"},{"idhaltestelle":"12","haltestellename":"haslach"},{"idhaltestelle":"13","haltestellename":"peilstein"},{"idhaltestelle":"14","haltestellename":"kollerschlag"},{"idhaltestelle":"15","haltestellename":"julbach"},{"idhaltestelle":"16","haltestellename":"nebelberg ost"},{"idhaltestelle":"17","haltestellename":"sarleinsbach"},{"idhaltestelle":"18","haltestellename":"htl neufelden"},{"idhaltestelle":"19","haltestellename":"niederwaldkirchen"},{"idhaltestelle":"20","haltestellename":"st. peter"},{"idhaltestelle":"21","haltestellename":"st. johann"},{"idhaltestelle":"22","haltestellename":"st, veit"},{"idhaltestelle":"23","haltestellename":"oberneukirchen"},{"idhaltestelle":"24","haltestellename":"herzogsdorf"},{"idhaltestelle":"25","haltestellename":"st, martin"},{"idhaltestelle":"26","haltestellename":"gramastetten"},{"idhaltestelle":"27","haltestellename":"linz hauptbahnhof"},{"idhaltestelle":"28","haltestellename":null},{"idhaltestelle":"29","haltestellename":"ottensheim"},{"idhaltestelle":"30","haltestellename":"walding"},{"idhaltestelle":"31","haltestellename":"gerling b127"},{"idhaltestelle":"32","haltestellename":"feldkirchen"},{"idhaltestelle":"33","haltestellename":"landshaag"},{"idhaltestelle":"34","haltestellename":"aschach bahnhof"},{"idhaltestelle":"35","haltestellename":"hartkirchen"},{"idhaltestelle":"36","haltestellename":"eferding"},{"idhaltestelle":"37","haltestellename":"haibach"},{"idhaltestelle":"38","haltestellename":"kirchberg ob der donau"},{"idhaltestelle":"39","haltestellename":null},{"idhaltestelle":"40","haltestellename":"lembach"},{"idhaltestelle":"41","haltestellename":"niederkappel"},{"idhaltestelle":"42","haltestellename":"pfarrkirchen"},{"idhaltestelle":"43","haltestellename":"hofkirchen"},{"idhaltestelle":"44","haltestellename":"neustift"},{"idhaltestelle":"45","haltestellename":"oberkappel"},{"idhaltestelle":"46","haltestellename":"niederranna"},{"idhaltestelle":"47","haltestellename":"waldkirchen"},{"idhaltestelle":"48","haltestellename":"neukirchen"},{"idhaltestelle":"49","haltestellename":"peuerbach"}] hope can me thanks!
try one:
arrayadapter<string> arrayadapter = new arrayadapter(this, android.r.layout.simple_list_item_1, results); i think u misunderstood way how use arrayadapter. have @ great tutorial
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