ios - swift : How to add icon image and image background to the UItabBar in App delegate?

Question

self.window = UIWindow(frame: UIScreen.mainScreen().bounds)

var nav1 = UINavigationController()
var first = ViewController(nibName: nil, bundle: nil)
nav1.viewControllers = [first]

var second = ccDiscovery(nibName: nil, bundle: nil)
var nav2 = UINavigationController()
nav2.viewControllers = [second]

var third = ccPosting(nibName: nil, bundle: nil)
var nav3 = UINavigationController()
nav3.viewControllers = [third]

var fourth = ccProfile(nibName: nil, bundle: nil)
var nav4 = UINavigationController()
nav4.viewControllers = [fourth]

var tabs = UITabBarController()
tabs.viewControllers = [nav1, nav2,nav3,nav4]

self.window!.rootViewController = tabs;
self.window?.makeKeyAndVisible();

如何给App delegate中的UItabBar添加图标图片和图片背景？我找不到。

UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.magentaColor()], forState:.Normal)
UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.redColor()], forState:.Selected)

Answer 1

UITabBarController 项在各个 View Controller 上设置 tabBarItem 属性:

var tabs = UITabBarController()
nav1.tabBarItem.image = UIImage(named: "some-image-1")
nav2.tabBarItem.image = UIImage(named: "some-image-2")
nav3.tabBarItem.image = UIImage(named: "some-image-3")
nav4.tabBarItem.image = UIImage(named: "some-image-4")
tabs.viewControllers = [nav1, nav2, nav3, nav4]