android - listview does not display -

im making project custom listview. when run project blank activity. wrote baseadapter class put data in listview. pass string arraylist baseadapter fill listview. help? thanks

  public class mainactivity extends activity {    listview l;  arraylist<string> data= new arraylist<string>(); @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);       data.add("two");     data.add("three");     data.add("four");     l=(listview) findviewbyid(r.id.listview1);      myadapter ada = new myadapter(mainactivity.this,data);     l.setadapter(ada);   }  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; } 

}

public class myadapter extends baseadapter {

context context; private arraylist<string> data=  new arraylist<string>();   public myadapter(context context ,arraylist<string> data )  {      this.context=context;      this.data=data;  }   @override public int getcount() {     // todo auto-generated method stub     return 0; }  @override public object getitem(int position) {     // todo auto-generated method stub     return null; }  @override public long getitemid(int position) {     // todo auto-generated method stub     return position; }  @override public view getview(int position, view convertview, viewgroup parent) {     // todo auto-generated method stub     viewholder holder;      convertview = null;     if (convertview == null) {         convertview = layoutinflater.from(context)           .inflate(r.layout.listlayout, parent, false);          holder = new viewholder();           holder.mainpic = (imageview)convertview.findviewbyid(r.id.imageview1);         holder.text= (textview)convertview.findviewbyid(r.id.textview1);         convertview.settag(holder);      }      else     {         holder = (viewholder) convertview.gettag();      }      holder.text.settext(this.data.get(position));       return convertview; }        static class viewholder {                  imageview mainpic;      textview text; }  

}

    <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:tools="http://schemas.android.com/tools"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:paddingbottom="@dimen/activity_vertical_margin"   android:paddingleft="@dimen/activity_horizontal_margin"   android:paddingright="@dimen/activity_horizontal_margin"   android:paddingtop="@dimen/activity_vertical_margin"  tools:context=".mainactivity" >  <listview     android:id="@+id/listview1"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:layout_alignparentleft="true"     android:layout_alignparenttop="true" >   </listview>  </relativelayout> 

change getcount() this:

@override public int getcount() {     return data.size(); } 

currently, return 0, tells listview there no items display.

also, might consider implementing getitem():

@override public object getitem(int position) {     return data.get(position); } 

and use items anywhere else.