arrays - How to populate ExpandableListView in Android at Runtime? -

array "feedback" contains keyword_id , feedback

eg.

{keyword_id= 1, feedback="test1"}, {keyword_id=1, feedback="test2"}, {keyword_id=2, feedback="test1"} 

so, want add every keyword_id listdataheader , feedback listdatachild. keyword_id=1 should show 2 feedbacks , keyword_id=2 should show feedback.

how can achieve that?

my current code able show keyword_id=1 , feedback="test1"

        try {             jsonobject jsonresponse;             jsonresponse = new jsonobject(result);             jsonarray jsonmainnode = jsonresponse.optjsonarray("feedbacks");             if(jsonmainnode != null) {                 int lengthjsonarr = jsonmainnode.length();                 (int = 0; < lengthjsonarr; i++) {                     listdataheader = new arraylist<string>();                     listdatachild = new hashmap<string, list<string>>();                     jsonobject jsonchildnode = jsonmainnode.getjsonobject(i);                     listdataheader.add(jsonchildnode.getstring("keyword_id"));                     list<string> key1 = new arraylist<string>();                     key1.add(jsonchildnode.getstring("feedback"));                     listdatachild.put(listdataheader.get(0), key1);                 }                 listadapter = new expandablelistadapter(getactivity(), listdataheader, listdatachild);                 explistview.setadapter(listadapter);             }         } catch (jsonexception e) {             e.printstacktrace();         } 

complete adapter class

public class expandablelistadapter extends baseexpandablelistadapter {      private context _context;     private list<string> _listdataheader;     private hashmap<string, list<string>> _listdatachild;      public expandablelistadapter(context context, list<string> listdataheader,                                  hashmap<string, list<string>> listchilddata) {         this._context = context;         this._listdataheader = listdataheader;         this._listdatachild = listchilddata;     }      @override     public object getchild(int groupposition, int childposititon) {         return this._listdatachild.get(this._listdataheader.get(groupposition))                 .get(childposititon);     }      @override     public long getchildid(int groupposition, int childposition) {         return childposition;     }      @override     public view getchildview(int groupposition, final int childposition,                              boolean islastchild, view convertview, viewgroup parent) {          final string childtext = (string) getchild(groupposition, childposition);          if (convertview == null) {             layoutinflater infalinflater = (layoutinflater) this._context                     .getsystemservice(context.layout_inflater_service);             convertview = infalinflater.inflate(r.layout.list_item, null);         }          textview txtlistchild = (textview) convertview                 .findviewbyid(r.id.lbllistitem);          txtlistchild.settext(childtext);         return convertview;     }      @override     public int getchildrencount(int groupposition) {         return this._listdatachild.get(this._listdataheader.get(groupposition))                 .size();     }      @override     public object getgroup(int groupposition) {         return this._listdataheader.get(groupposition);     }      @override     public int getgroupcount() {         return this._listdataheader.size();     }      @override     public long getgroupid(int groupposition) {         return groupposition;     }      @override     public view getgroupview(int groupposition, boolean isexpanded,                              view convertview, viewgroup parent) {         string headertitle = (string) getgroup(groupposition);         if (convertview == null) {             layoutinflater infalinflater = (layoutinflater) this._context                     .getsystemservice(context.layout_inflater_service);             convertview = infalinflater.inflate(r.layout.list_group, null);         }          textview lbllistheader = (textview) convertview                 .findviewbyid(r.id.lbllistheader);         lbllistheader.settypeface(null, typeface.bold);         lbllistheader.settext(headertitle);          return convertview;     }      @override     public boolean hasstableids() {         return false;     }      @override     public boolean ischildselectable(int groupposition, int childposition) {         return true;     }  } 

sometimes it's easier let 3rd party library heavy lifting you. suggest using nfrolodexarrayadapter. works great situations yours header of object can determined object itself. there's plenty of example code using on repo , demo app well.

your code following:

the activity

    //convert jsonarray arraylist     arraylist<jsonobject> listdata = new arraylist<>();          int lengthjsonarr = jsonmainnode.length();     (int = 0; < lengthjsonarr; ++i){          listdata.add(jsonmainnode.getjsonobject(i));     }      //just pass in arraylist of jsonobjects. adapter handle sorting appropriate headers     myexpandablelistadapter adapter = new myexpandablelistadapter(this, listdata);     explistview.setadapter(adapter); 

the adapter

private class myexpandablelistadapter extends nfrolodexarrayadapter<string, jsonobject> {      public myexpandablelistadapter(context activity, collection<jsonobject> items) {         super(activity, items);     }      @override     public date creategroupfor(jsonobject childitem) {         //this how adapter determines headers , child items belong         return childitem.getstring("keyword_id");     }      @override     public view getchildview(layoutinflater inflater, int groupposition, int childposition,                              boolean islastchild, view convertview, viewgroup parent) {         //inflate view          //get jsonobject data view         jsonobject data = getchild(groupposition, childposition);          //fill view data     }      @override     public view getgroupview(layoutinflater inflater, int groupposition, boolean isexpanded,                              view convertview, viewgroup parent) {         //inflate header view          //gets header string view         string headertitle = getgroup(groupposition);          //fill view headertitle     } }