ViewHolder最简洁的写法

通用viewHolder工具类：

public class ViewHolder {
    // I added a generic return type to reduce the casting noise in client code
    @SuppressWarnings("unchecked")
    public static <T extends View> T get(View view, int id) {
        SparseArray<View> viewHolder = (SparseArray<View>) view.getTag();
        if (viewHolder == null) {
            viewHolder = new SparseArray<View>();
            view.setTag(viewHolder);
        }
        View childView = viewHolder.get(id);
        if (childView == null) {
            childView = view.findViewById(id);
            viewHolder.put(id, childView);
        }
        return (T) childView;
    }
}

getview中的写法：

public View getView(int position, View convertView, ViewGroup parent) {

    if (convertView == null) {
        convertView = LayoutInflater.from(context)
          .inflate(R.layout.banana_phone, parent, false);
    }

    TextView ageTv = ViewHolder.get(convertView, R.id.agetv);
    TextView nameTv = ViewHolder.get(convertView, R.id.nametv);

    Student student = getItem(position);
    ageTv .setText(student.getAge());
    nameTv.setText(student.getName()); 
    return convertView;
}