[Android] Simple question

BaseAdapter First time BaseAdapter, select the part of the report following a null pointer , to help look.


see at night are written : holder.apptitle.setText (. (String) list.get (position) get ("apptitle"));
But I write compiled through ah. .
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landlord has the wrong places , findViewById signature fewer things.

holder.apptitle = (TextView)convertView.findViewById(R.id.tv_item1);
  holder.apptico = (TextView)convertView.findViewById(R.id.tv_item);

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you can put a little detail? ? My new infrastructure is poor
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public View getView (int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
holder = new ViewHolder ();
convertView = inflater.inflate (R.layout.list, null);
holder.apptitle = (TextView) convertView.findViewById (R.id.tv_item1);
; holder.apptico = (TextView) convertView.findViewById (R.id.tv_item);
convertView.setTag (holder);
}
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positive solution ! But ViewHolder holder = null; feeling a little redundant
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really is the problem. . Here even wrong . .
Thank you ah ! !
------ eference --------------------------------------- < br> there is a problem , ah, I write , it seems intelligent display an Item data ah , this should be how to solve ah ?