createViewFromTag(context, name, attrs);什么时候知道到这个呢？

` 
  public View onCreateView(View parent, String name, Context context, AttributeSet attrs){
.......
if (view == null)
        {
            Log.e("linbin","888888");
            view = createViewFromTag(context, name, attrs);
        }
}
.......
`

这里是什么情况下view == null呢
