Why doesn't my Viewholder work? - nullpointerexception

Question

So I'm creating a List for which I'm using my own implementation of the array adapter. I'm also using a viewholder for performance. But for some reason I get a nullpointer exception at this line:
holder.icon.setImageResource(R.drawable.no);
So I guess my holder isn't initialized? But I don't see how else my code should be?
public class NameViewAdapter extends ArrayAdapter<String>{
private String[] names;
private static class ViewHolder{
ImageView icon=null;
}
public NameViewAdapter(Context context, int textViewResourceId,String[] names) {
super(context, textViewResourceId, names);
this.names = names;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if(convertView==null)
{
LayoutInflater li =
(LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = li.inflate(R.layout.row,parent,false);
holder=new ViewHolder();
holder.icon=(ImageView) convertView.findViewById(R.id.icon);
convertView.setTag(holder);
}
else
{
holder = (ViewHolder) convertView.getTag();
}
if (names[position].length() > 4)
holder.icon.setImageResource(R.drawable.ok);
else
holder.icon.setImageResource(R.drawable.no);
return convertView;
}
}
This is my XML-file:
<?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">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/imageView"
android:src="#drawable/ic_launcher"/>
<TextView
android:id="#+id/label"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

Answer 1

K so it seemed that the next line:
holder.icon=(ImageView) convertView.findViewById(R.id.icon);
should be changed to
holder.icon=(ImageView) convertView.findViewById(R.id.imageView);
cause that's the id the ImageView has in the xml file