listview - Android ExpandableListview -

any tutorial expandablelistview android fold animation ? m using adapter it's not smooth don't know why , suggestions smooth adapter , how can include fold animation while collapse , expand

my adapter :

public class customlistadapter extends baseexpandablelistadapter {  list<categoriesobject> categoriesobjectlist;  context context;  imageview rightimage; imageview iconimage; public layoutinflater inflater; public servicehelper servicehandler; imageloader imgloader;  public customlistadapter(activity context, list<categoriesobject> categoriesobjectlist) {     // super(context, r.layout.list_content_row);     // todo auto-generated constructor stub     this.categoriesobjectlist = categoriesobjectlist;     this.context = context;     inflater = context.getlayoutinflater();     imgloader = new imageloader(context); }  @override public serviceobject getchild(int groupposition, int childposition) {     list<serviceobject> chlist = categoriesobjectlist.get(groupposition).services;     return chlist.get(childposition); }  @override public long getchildid(int groupposition, int childposition) {     return childposition; }  @override public view getchildview(int groupposition, int childposition,                          boolean islastchild, view convertview, viewgroup parent) {      serviceobject child = (serviceobject) getchild(groupposition, childposition);     if (convertview == null) {         layoutinflater infalinflater = (layoutinflater) context                 .getsystemservice(context.layout_inflater_service);         convertview = infalinflater.inflate(r.layout.servicelist_content_row, null);     }      servicesmanager.setcontext(this.context);     if(servicesmanager.serviceisselected(child))     {         convertview.findviewbyid(r.id.menutitle).setbackgroundcolor(color.parsecolor("#cc0fcb9e"));         rotateanimation anim = new rotateanimation(0f,45f, animation.relative_to_self, 0.5f, animation.relative_to_self,                 0.5f);         // step 2:  set animation properties          anim.setrepeatcount(0);         anim.setinterpolator(new linearinterpolator());         anim.setduration(1200);         anim.setfillafter(true);          // step 3: start animating image         imageview leftimage  = (imageview)convertview.findviewbyid(r.id.leftimage);         leftimage.startanimation(anim);     }     else     {         convertview.findviewbyid(r.id.menutitle).setbackgroundcolor(color.parsecolor("#cc0fcb9e"));         rotateanimation anim = new rotateanimation(45f, 0f, animation.relative_to_self, 0.5f, animation.relative_to_self,                 0.5f);         // step 2:  set animation properties          anim.setrepeatcount(0);         anim.setinterpolator(new linearinterpolator());         anim.setduration(1200);         anim.setfillafter(true);          // step 3: start animating image         imageview leftimage  = (imageview)convertview.findviewbyid(r.id.leftimage);         leftimage.startanimation(anim);         convertview.findviewbyid(r.id.menutitle).setbackgroundcolor(color.parsecolor("#cc2e5c78"));     }        final textview tv = (textview) convertview.findviewbyid(r.id.title);      textview price = (textview) convertview.findviewbyid(r.id.pricetxt);     tv.settext(child.servicename.tostring());     price.settext(string.valueof(child.serviceprice));      return convertview; }  @override public int getchildrencount(int groupposition) {     list<serviceobject> chlist = categoriesobjectlist.get(groupposition).services;     return chlist.size(); }  @override public categoriesobject getgroup(int groupposition) {     return categoriesobjectlist.get(groupposition); }  @override public int getgroupcount() {     return categoriesobjectlist.size(); }  @override public long getgroupid(int groupposition) {     return groupposition; }  @override public view getgroupview(int groupposition, boolean isexpanded,                          view convertview, viewgroup parent) {     categoriesobject group = (categoriesobject) getgroup(groupposition);     if (convertview == null) {         layoutinflater inf = (layoutinflater) context                 .getsystemservice(context.layout_inflater_service);         convertview = inf.inflate(r.layout.list_content_row, null);     }     textview tv = (textview) convertview.findviewbyid(r.id.title);     imageview iconimage = (imageview)convertview.findviewbyid(r.id.iconimage);        imgloader.displayimage(group.catimage,iconimage);   //  new imageloadtask(group.catimage, iconimage).execute();      tv.settext(group.catname);     return convertview; }  @override public boolean hasstableids() {     return true; }  @override public boolean ischildselectable(int groupposition, int childposition) {     return true; }   private static class childholder {     textview title;     textview hint; }  public interface servicehelper {     public void serviceclicked(int grouppos, int childpos); } 

}

check out: animated expandable listview