在Swift中选择的UIPickerView行的动画背景颜色。

I want to change background color of selected row in UIPickerView with animation. I'm reloading all components when a new row selected and in viewForRow function If current row is selected one, I make Its' background color to red. However, It looks like in bug. First screen shot is what I want to achieve and second one is in my app. Btw, It will be excellent If I can set that red color with animationI want to change background color of selected r