ios - fill part of a UIView with color with animation -

i need create effect of filling uiview color, animation. example battery image filled background color .

so can see problem 2 :

1. background color of uiview part of ( 10% / 45% /etc )
2. make animation

how color part of uiview natively? (obj-c)

uiview *view=[uiview alloc] init]; view.backgroundcolor=[uicolor redcolor]; //is colouring of . 

creating 2 views problem,because need animate whole thing fills color .

you use 2 views, not problem if put second view subview first. way can animate outer view , inner follow.

to show battery level animate frame of inner view.