extend BaseAdapter，什么时候view是空值

Question

public class CustomAdapter extends BaseAdapter

extend BaseAdapter代码：

        public View getView(int index, View view, final ViewGroup parent) {

            if (view == null) {
                LayoutInflater inflater = LayoutInflater.from(parent.getContext());
                view = inflater.inflate(R.layout.single_list_item, parent, false);
            }
    }

 TextView textView = (TextView) view.findViewById(R.id.tv_string_data);
        textView.setText(dataModel.getName());

我的问题是什么时候view == null？

为什么需要代码：if (view == null) {}

Answer 1

view会被复用，所以会有null和非null。