android - ListViewAdapter changing few buttons -

i created adapter list view. want click on button , change text on it. when click button few buttons changed not this.

this listviewadapter.java

public class listviewadapter extends arrayadapter<post> {     private list<post> mpostlist;     private context mcontext;  public listviewadapter(list<post> postlist, context context){     super(context, r.layout.post, postlist);     mpostlist = postlist;     mcontext = context; }  public view getview(final int position, view convertview, viewgroup parent){     final viewholderitem viewholder;     if(convertview==null){         convertview = layoutinflater.from(getcontext()).inflate(r.layout.post, parent, false);         viewholder = new viewholderitem();         convertview.settag(viewholder);         viewholder.mplusimagebutton.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 viewholder.mplusimagebutton.settext("a");             }         });     }else{         viewholder = (viewholderitem) convertview.gettag();     }      return convertview; }      static class viewholderitem {          public button mplusimagebutton;          public int position;     }  @override public int getcount(){     return mpostlist.size(); } 

}

here can create boolean variable inside post class , instantiate false whenever button clicked make true , inside getview method make use of variable. getview method below.

public view getview(final int position, view convertview, viewgroup parent){ final viewholderitem viewholder; if(convertview==null){     convertview = layoutinflater.from(getcontext()).inflate(r.layout.post, parent, false);     viewholder = new viewholderitem();     viewholder.mplusimagebutton = convertview.findviewbyid(r.id.someid);     viewholder.mplusimagebutton = convertview.findviewbyid(r.id.someid);     convertview.settag(viewholder);  }else{     viewholder = (viewholderitem) convertview.gettag(); } post post = mpostlist.get(position); viewholder.mplusimagebutton.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 viewholder.mplusimagebutton.settext("a");                 post.isclicked = true;             }     });     if(post.isclicked)     viewholder.mplusimagebutton.settext("a");     else     viewholder.mplusimagebutton.settext("b");     return convertview; }