BaseAdapter causing ListView to go out of order when scrolled

Question

I\'m having problems with some BaseAdapter code that I adapted from a book. I\'ve been using variations of this code all over the place in my application, but only just real

Answer 1

You are only putting data in the TextView widgets when they are first created. You need to move these four lines:

        TextView label = (TextView)view.findViewById(R.id.groups_item_title);
        label.setText(mContacts.get(position).getName());
        label = (TextView)view.findViewById(R.id.groups_item_subtitle);
        label.setText(mContacts.get(position).getNumber());

to be after the if/else block and before the method return, so you update the TextView widgets whether you are recycling the row or creating a fresh one.

Answer 2

To further clarify the answer of CommonsWare, here is some more info:

The li.inflate operation (needed here for parsing of the layout of a row from XML and creating the appropriate View object) is wrapped by an if (convertView == null) statement for efficiency, so the inflation of the same object will not happen again and again every time it pops into view.

HOWEVER, the other parts of the getView method are used to set other parameters and therefore should NOT be included within the if (convertView == null){ }... else{ } statement.

In many common implementation of this method, some textView label, ImageView or ImageButton elements need to be populated by values from the list[position], using findViewById and after that .setText or .setImageBitmap operations. These operations must come after both creating a view from scratch by inflation and getting an existing view if not null (e.g. on a refresh).

Another good example where this solution is applied for a ListView ArrayAdapter appears in https://stackoverflow.com/a/3874639/978329