Android: system call getView twice when activity created
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i am new
I have custom list with about 20 item and three lines each item. 
I put Log to trace how to getView method called

public View getView(int position, View convertView, ViewGroup parent) {
		
		Log.e("getView", "at position " + position);
		View view = convertView;

		if (view == null) {
			LayoutInflater inflater = ((Activity) context).getLayoutInflater();
			view = inflater.inflate(resourceId, parent, false);
		}
                  // my code here

	}

Then, when list item loaded, i received this log

"getView", "at position 0"; 
"getView", "at position 1"; 
"getView", "at position 2"; 
"getView", "at position 3"; 
"getView", "at position 0"; 
"getView", "at position 1"; 
"getView", "at position 2"; 
"getView", "at position 3"; 
"getView", "at position 4"; 
"getView", "at position 5"; 
..............


Any one show me why getView method called twice from 0 to 3 ?
Many thanks