android - Checking a radioButton in RecyclerView makes other random radiobutton checked too -

im new in recyclerview , when use radiogroup 4 radiobutton in recyclerview.every things works fine, when scroll down in recyclerview radio button randomly checked in position layout row_mylist.xml

      <radiogroup>               <radiobutton             android:text="radiobutton"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:id="@+id/btn_radio_test2"             android:button="@null"             android:drawableright="?android:attr/listchoiceindicatorsingle"             android:layout_weight="1"             android:gravity="right|center_vertical"             android:textsize="10sp" />          <radiobutton             android:text="radiobutton"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:id="@+id/btn_radio_test3"             android:button="@null"             android:drawableright="?android:attr/listchoiceindicatorsingle"             android:layout_weight="1"             android:gravity="right|center_vertical"             android:textsize="10sp" />          <radiobutton             android:text="radiobutton"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:id="@+id/btn_radio_test1"             android:layout_weight="1"             android:button="@null"             android:drawableright="?android:attr/listchoiceindicatorsingle"             android:gravity="right|center_vertical"             android:textsize="10sp" />          <radiobutton             android:text="radiobutton"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:id="@+id/btn_radio_test4"             android:layout_weight="1"             android:button="@null"             android:drawableright="?android:attr/listchoiceindicatorsingle"             android:gravity="right|center_vertical"             android:textsize="10sp" />          <radiogroup             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:orientation="vertical"             android:id="@+id/radiogp_testi"             android:layout_margintop="20dp"             android:layout_marginbottom="10dp"             android:layout_marginleft="5dp"             android:layout_marginright="5dp"             >          </radiogroup> 

my adapter code

public class adapterquiz extends recyclerview.adapter<adapterquiz.myviewholder> { private activity context; private arraylist<hashmap<string,string>>quizs=new arraylist<>(); private static hashmap<string,string>hashmap;  public adapterquiz(final activity context, arraylist<hashmap<string,string>>quizs){     this.context=context;     this.quizs=quizs;  }  @override public myviewholder oncreateviewholder(viewgroup parent, int viewtype) {     view view;     view= layoutinflater.from(context).inflate(r.layout.row_soalat,parent,false);     return new myviewholder(view); }  @override public void onbindviewholder(final myviewholder holder, final int position) {      hashmap=new hashmap<>();     hashmap=quizs.get(position);   holder.rgtesti.setoncheckedchangelistener(new radiogroup.oncheckedchangelistener() {             @override             public void oncheckedchanged(radiogroup radiogroup, int i) {                  switch (i){                     case r.id.btn_radio_test1:                         //show toast                         break;                     case r.id.btn_radio_test2:                         //show toast                         break;                     case r.id.btn_radio_test3:                         //show toast                         break;                     case r.id.btn_radio_test4:                         //show toast                         break;                  }              }         });     }   } 

your on wrong track... wrap radio buttons inside radio group.