So, what is ViewHolder? Especially in Android programing.
I found this in Stack Overflow. Yeahh…
ViewHolderdesign pattern is used to speed up rendering of your
ListView– actually to make it work smoothly, findViewById is quite expensive (it does DOM parsing) when used each time a list item is rendered, it must traverse your layout hierarchy and also instantiate objects. Since lists can redraw its items quite frequently during scrolling such overhead might be substantial. (21501316)
As simple as that. Wow!