android - Why correct alphabet is not shown in TextView? -

i'm making android app implementing custom listview of names. want list displayed in lexicographic order , on change of first character in name,the corresponding character should displayed before names starting character begin.but not happening correctly.i can't understand reason. secondly, whatever list generated,on fast scrolling first letters disappear , i'm left sorted list without first alphabet markings. please help.. in advance. snapshots: before scrolling after scrolling multiple times

row_item_speaker.xml

<?xml version="1.0" encoding="utf-8"?>   <linearlayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical">       <textview         android:id="@+id/tv_first_alphabet"         android:paddingtop="10dp"         android:layout_width="wrap_content"         android:layout_height="match_parent"         android:text="a"         android:textstyle="bold"         android:textcolor="@color/colorprimary"/>      <view         android:id="@+id/horizontalline"         android:layout_width="match_parent"         android:layout_height="1dp"         android:background="@color/colorprimary"/>      <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:app="http://schemas.android.com/apk/res-auto"     android:orientation="vertical"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:padding="10dp">      <com.pkmmte.view.circularimageview         android:id="@+id/civ_speaker_photo"         android:layout_width="60dp"         android:layout_height="60dp"         android:src="@drawable/ic_speakers"         app:border="true"         app:border_color="#eeeeee"         app:border_width="2dp"         android:paddingleft="5dp"         android:paddingstart="5dp"         app:shadow="true" />       <textview     android:id="@+id/tv_speaker_name"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:textsize="@dimen/heading_size"     android:textcolor="#000"     android:textstyle="bold"     android:paddingleft="10dp"     android:paddingstart="10dp"     android:layout_toendof="@id/civ_speaker_photo"     android:layout_torightof="@id/civ_speaker_photo"     android:layout_aligntop="@id/civ_user_pic"     android:paddingtop="8dp"/>      <textview         android:id="@+id/tv_speaker_position"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_torightof="@id/civ_speaker_photo"         android:layout_toendof="@id/civ_speaker_photo"         android:layout_below="@id/tv_speaker_name"         android:textsize="@dimen/subheading_size"         android:textcolor="#777"         android:ellipsize="end"         android:singleline="true"         android:paddingleft="10dp"         android:paddingstart="10dp"         /> </relativelayout>   </linearlayout> 

speakeradapter.java

package com.test.rajat.a10times.adapter;  import android.content.context; import android.graphics.color; import android.util.log; import android.view.layoutinflater; import android.view.view; import android.view.viewgroup; import android.widget.baseadapter; import android.widget.textview;  import com.pkmmte.view.circularimageview; import com.squareup.picasso.picasso; import com.test.rajat.a10times.model.speakermodel; import com.test.rajat.a10times.r;  import java.util.arraylist; import java.util.collections; import java.util.comparator;  /**  * created rajat on 1/20/2016.  */ public class speakersadapter extends baseadapter {      private context context;     private arraylist<speakermodel> speakerslist;      public speakersadapter(context context, arraylist<speakermodel> speakerslist) {         this.context = context;         this.speakerslist = speakerslist;         sortedlist();     }      private arraylist<speakermodel> sortedlist(){         collections.sort(speakerslist, new comparator<speakermodel>() {             @override             public int compare(speakermodel s1, speakermodel s2) {                 return s1.getname().comparetoignorecase(s2.getname());             }         });          return speakerslist;     }      @override     public int getcount() {         return speakerslist.size();     }      @override     public object getitem(int position) {         return speakerslist.get(position);     }      @override     public long getitemid(int position) {         return position;     }      @override     public view getview(int position, view convertview, viewgroup parent) {         if(convertview==null)         {             layoutinflater inflater=(layoutinflater) context.getsystemservice(context.layout_inflater_service);             convertview=inflater.inflate(r.layout.row_item_speaker,null);         }          textview name=(textview) convertview.findviewbyid(r.id.tv_speaker_name);         textview speaker_position=(textview) convertview.findviewbyid(r.id.tv_speaker_position);         textview first_alphabet=(textview) convertview.findviewbyid(r.id.tv_first_alphabet);         view horizontalline= convertview.findviewbyid(r.id.horizontalline);          if(setfirstalphabet(position)){             first_alphabet.settext((speakerslist.get(position).getname().subsequence(0, 1).tostring()));         }         else{             first_alphabet.setvisibility(view.gone);             horizontalline.setbackgroundcolor(color.parsecolor("#d3d3d3"));         }         circularimageview image=(circularimageview) convertview.findviewbyid(r.id.civ_speaker_photo);         picasso.with(context).load(speakerslist.get(position).getpic_url()).placeholder(r.drawable.ic_person).error(r.drawable.ic_person).into(image);         name.settext(speakerslist.get(position).getname());         speaker_position.settext(speakerslist.get(position).getposition());         return convertview;     }      private boolean setfirstalphabet(int position){         string currentfirstalphabet=speakerslist.get(position).getname().subsequence(0,1).tostring();         string nextfirstalphabet=speakerslist.get(position+1).getname().subsequence(0,1).tostring();         if(position<speakerslist.size()-1) {             if ((currentfirstalphabet.comparetoignorecase(nextfirstalphabet) == 0)) {                 log.d("tag3",speakerslist.get(position).getname().subsequence(0,1).tostring()+speakerslist.get(position+1).getname().subsequence(0,1).tostring());                 return false;             }         }         return true;     } }