android - Update ViewPager Based on Dynamic Data in Firebase -
i creating polling app in realtime using firebase.
every day, adding new polls firebase category have under directory polls > dates > respective date > poll 1, poll 2, poll 3. want update viewpager display polls current day.
each poll have image, question, answer choices, total vote count, , several other components.
basically, want viewpager display each poll particular day. manually update data in firebase, , hoping firebase listeners in client/java code can update data dynamically. polls each unique instance of homepollsfragment, , having difficulty changing individual fragments display in viewpager particular day.
i trying handle changes in getitemposition() override method of fragmentstatepageradapter, , trying override "view comments" textview in included screenshot (i update else later, doing "view comments" simplicity). "view comments" state "test comments poll 1" first poll, , "test comments poll 2" second poll.
below mainactivity, create viewpager, , homepollsfragment:
mainactivity
public class mainactivity extends appcompatactivity implements homepollsfragment.onfragmentinteractionlistener { private toolbar toolbar; private fragmentmanager fm; private static final string firebase_url = "https://fan-polls.firebaseio.com/"; private firebase mbaseref; private firebase muserref; private firebase mpollsref; private static final string poll_frag_tag = "poll_frag"; private static final string prefs_frag_tag = "prefs_frag"; private static final string request_poll_frag_rag = "request_poll_frag"; private viewpager mpager; private fragmentstatepageradapter mpageradapter; private int mpollcountforcurrentday; private dateformat mdateformat; private date mdate; private string mcurrentdatestring; private string mpollquestion; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_home); toolbar = (toolbar) findviewbyid(r.id.tool_bar); setsupportactionbar(toolbar); createnavdrawer(); //write firebase mbaseref = new firebase(firebase_url); muserref = mbaseref.child("users"); mpollsref = mbaseref.child("polls"); //set viewpager current day mpager = (viewpager) findviewbyid(r.id.home_polls_viewpager); mpageradapter = new screenslidepageradapter(getsupportfragmentmanager()); mpager.setadapter(mpageradapter); //terminate loading activity has no value after sending user appropriate screen loadingactivity.loadingactivity.finish(); //get current date apply viewpager mdateformat = new simpledateformat("dd-mm-yyyy"); mdate = new date(); mcurrentdatestring = mdateformat.format(mdate); } @override protected void onstart() { super.onstart(); mpollsref.addvalueeventlistener(new valueeventlistener() { //testing methodology of adding children @override public void ondatachange(datasnapshot datasnapshot) { mpollcountforcurrentday = (int) datasnapshot.child(mcurrentdatestring).getchildrencount(); mpageradapter.notifydatasetchanged(); log.i("tag", "there " + string.valueof(mpollcountforcurrentday) + " children in today's poll count."); } @override public void oncancelled(firebaseerror firebaseerror) { } }); } //close firebase eventlistener @override protected void onstop() { super.onstop(); } @override public void onfragmentinteraction(uri uri) { } private class screenslidepageradapter extends fragmentstatepageradapter { public screenslidepageradapter(fragmentmanager fm) { super(fm); } @override public fragment getitem(int position) { return new homepollsfragment(); } @override public int getcount() { return mpollcountforcurrentday; } @override public int getitemposition(object object) { final object mobject = object; mpollsref.addvalueeventlistener(new valueeventlistener() { @override public void ondatachange(datasnapshot datasnapshot) { (int = 1; <= mpollcountforcurrentday; i++) { homepollsfragment frag = (homepollsfragment) mobject; frag.mnumberofpollchildren.settext((string) datasnapshot.child(mcurrentdatestring).child(string.valueof(i)).child("poll_question").getvalue()); } } @override public void oncancelled(firebaseerror firebaseerror) { } }); return super.getitemposition(object); } } @override public void onbackpressed() { super.onbackpressed(); super.onbackpressed(); if (mpager.getcurrentitem() == 0) { // if user looking @ first step, allow system handle // button. calls finish() on activity , pops stack. super.onbackpressed(); } else { // otherwise, select previous step. mpager.setcurrentitem(mpager.getcurrentitem() - 1); } } } homepollsfragment, trying create new instance of different question, answer, , other info each day (the viewpager should dynamically update each day polls on given day):
public class homepollsfragment extends fragment { // todo: rename parameter arguments, choose names match // fragment initialization parameters, e.g. arg_item_number private static final string arg_param1 = "param1"; private static final string arg_param2 = "param2"; // todo: rename , change types of parameters private string mparam1; private string mparam2; public textview mnumberofpollchildren; private firebase mbaseref; private firebase mpollsref; private static final string firebase_url = "https://fan-polls.firebaseio.com/"; //all date items; dynamic private int mpollcountforcurrentday; private dateformat mdateformat; private date mdate; private string mcurrentdatestring; private onfragmentinteractionlistener mlistener; public homepollsfragment() { // required empty public constructor } /** * use factory method create new instance of * fragment using provided parameters. * * @param param1 parameter 1. * @param param2 parameter 2. * @return new instance of fragment homepollsfragment. */ // todo: rename , change types , number of parameters public static homepollsfragment newinstance(string param1, string param2) { homepollsfragment fragment = new homepollsfragment(); bundle args = new bundle(); args.putstring(arg_param1, param1); args.putstring(arg_param2, param2); fragment.setarguments(args); return fragment; } @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); mbaseref = new firebase(firebase_url); mpollsref = mbaseref.child("polls"); //get current date apply viewpager mdateformat = new simpledateformat("dd-mm-yyyy"); mdate = new date(); mcurrentdatestring = mdateformat.format(mdate); if (getarguments() != null) { mparam1 = getarguments().getstring(arg_param1); mparam2 = getarguments().getstring(arg_param2); } } @override public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) { // inflate layout fragment viewgroup rootview = (viewgroup) inflater.inflate(r.layout.fragment_poll, container, false); mnumberofpollchildren = (textview) rootview.findviewbyid(r.id.comments_textview); return rootview; } @override public void onstart() { super.onstart(); mpollsref.addvalueeventlistener(new valueeventlistener() { @override public void ondatachange(datasnapshot datasnapshot) { mpollcountforcurrentday = (int) datasnapshot.child(mcurrentdatestring).getchildrencount(); log.i("tag", "there " + string.valueof(mpollcountforcurrentday) + " children in today's pollllll count."); } @override public void oncancelled(firebaseerror firebaseerror) { } }); } //close event listener onstop @override public void onstop() { super.onstop(); } // todo: rename method, update argument , hook method ui event public void onbuttonpressed(uri uri) { if (mlistener != null) { mlistener.onfragmentinteraction(uri); } } @override public void onattach(context context) { super.onattach(context); if (context instanceof onfragmentinteractionlistener) { mlistener = (onfragmentinteractionlistener) context; } else { throw new runtimeexception(context.tostring() + " must implement onfragmentinteractionlistener"); } } @override public void ondetach() { super.ondetach(); mlistener = null; } /** * interface must implemented activities contain * fragment allow interaction in fragment communicated * activity , potentially other fragments contained in * activity. * <p/> * see android training lesson <a href= * "http://developer.android.com/training/basics/fragments/communicating.html" * >communicating other fragments</a> more information. */ public interface onfragmentinteractionlistener { // todo: update argument type , name void onfragmentinteraction(uri uri); } } example of poll design view comments textview:
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