UITabBar不会改变它的背景颜色

Easy code

class PreferencesTabBar: UITabBar {


    override func drawRect(rect: CGRect) {
        super.drawRect(rect)
        self.backgroundColor = UIColor(red: 166.0/255.0, green: 142.0/255.0, blue: 83.0/255.0, alpha: 0.5)
    }

}
class PreferencesTabBar: UITabBar {