TabBarController

直接control drag 點選viewController就可以新增物件

要設置item的名字雙擊內部MVC的item即可改名

FaceIt Demo

Demo使用了split view controller和Navigation Controller
好讓ipad和iphone都可以使用

跟tab bar很像，split view也是control drag選擇detail或master
這邊 demo 新增了一個 view controller "EmotionViewController"
file>new>file>cocoatouch class

裡面的 prepare 透過 identifier 讓你控制臉部表情

   override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let vc = segue.destination
        if let faceViewController = vc as? FaceViewController{
            switch segue.identifier! {
            case "Happy":
                faceViewController.expression = FacialExpression(eye: .Open, brow: .Normal, mouth: .Happy)
                break
            case "Angry":
                faceViewController.expression = FacialExpression(eye: .Open, brow: .Normal, mouth: .Sad)
                break
            default:
                break
            }
        }

ViewController Life Cycle

1.instantiate from storyboard >
2.awakeFromNib >
3.segues prepare >
4.outlet set >
5.view did load >

當你view消失或出現這兩個方法會被呼叫
1.viewWillAppear
2.viewWillDisappear

當geometry change這個方法會在viewDidLoad後被呼叫
viewWillLayoutSubView

當記憶體低落時
didRceiveMemoryWaring