MVVM和MVC模式中的视图创build在哪里？

请原谅，如果其重复的话题。

我通常写我的应用程序没有故事板，并将视图创build到“viewDidLoad”，如：

class LoginVC: UIViewController { var view1: UIView! var label1: UILabel! override func viewDidLoad() { super.viewDidLoad() loadStaticViews() } func loadStaticViews() { view1 = UIView() label1 = UILabel() view.addSubview(view1) view1.addSubview(label1) // constraints... } } 

现在我想尝试在我的下一个应用程序的MVVM模式，只是不知道在哪里把视图创build。 现在我想到了这样的事情：

 class LoginVCViews { static func loadViews<T, T1, T2>(superview: UnsafeMutablePointer<T>, view: UnsafeMutablePointer<T1>, label: UnsafeMutablePointer<T2>) { guard let superview = superview.pointee as? UIView else { return } let v = UIView() let l = UILabel() superview.addSubview(v) v.addSubview(l) // constraints... view.pointee = v as! T1 label.pointee = l as! T2 } } class LoginVC: UIViewController { private var view1: UIView! private var label1: UILabel! override func viewDidLoad() { super.viewDidLoad() LoginVCViews.loadViews(superview: &view, view: &view1, label: &label1) } } 

你怎么看 ？ 我不太熟悉UnsafeMutablePointer，不确定会不会有一些问题。 还有多丑呢？

Answer 1

也许你应该尝试完全面向对象的path。 一个视图组成看起来像这样：

//可重用的协议集

 protocol OOString: class { var value: String { get } } protocol Executable: class { func execute() } protocol Screen: class { var ui: UIViewController { get } } protocol ViewRepresentation: class { var ui: UIView { get } } 

//可重用的function（没有uikit依赖）

 final class ConstString: OOString { init(_ value: String) { self.value = value } let value: String } final class ExDoNothing: Executable { func execute() { /* do nothing */ } } final class ExObjCCompatibility: NSObject, Executable { init(decorated: Executable) { self.decorated = decorated } func execute() { decorated.execute() } private let decorated: Executable } 

//可重用的UI（uikit依赖）

 final class VrLabel: ViewRepresentation { init(text: OOString) { self.text = text } var ui: UIView { get { let label = UILabel() label.text = text.value label.textColor = UIColor.blue return label } } private let text: OOString } final class VrButton: ViewRepresentation { init(text: OOString, action: Executable) { self.text = text self.action = ExObjCCompatibility(decorated: action) } var ui: UIView { get { let button = UIButton() button.setTitle(text.value, for: .normal) button.addTarget(action, action: #selector(ExObjCCompatibility.execute), for: .touchUpInside) return button } } private let text: OOString private let action: ExObjCCompatibility } final class VrComposedView: ViewRepresentation { init(first: ViewRepresentation, second: ViewRepresentation) { self.first = first self.second = second } var ui: UIView { get { let view = UIView() view.backgroundColor = UIColor.lightGray let firstUI = first.ui view.addSubview(firstUI) firstUI.translatesAutoresizingMaskIntoConstraints = false firstUI.topAnchor.constraint(equalTo: view.topAnchor, constant: 100).isActive = true firstUI.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20).isActive = true firstUI.widthAnchor.constraint(equalToConstant: 100).isActive = true firstUI.heightAnchor.constraint(equalToConstant: 40).isActive = true let secondUI = second.ui view.addSubview(secondUI) secondUI.translatesAutoresizingMaskIntoConstraints = false secondUI.topAnchor.constraint(equalTo: firstUI.topAnchor).isActive = true secondUI.leadingAnchor.constraint(equalTo: firstUI.trailingAnchor, constant: 20).isActive = true secondUI.widthAnchor.constraint(equalToConstant: 80).isActive = true secondUI.heightAnchor.constraint(equalToConstant: 40).isActive = true return view } } private let first: ViewRepresentation private let second: ViewRepresentation } 

//视图控制器

 final class ContentViewController: UIViewController { convenience override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) { self.init() } convenience required init(coder aDecoder: NSCoder) { self.init() } convenience init() { fatalError("Not supported!") } init(content: ViewRepresentation) { self.content = content super.init(nibName: nil, bundle: nil) } override func loadView() { view = content.ui } private let content: ViewRepresentation } 

//现在屏幕的业务逻辑（不可重复使用）

 final class ScStartScreen: Screen { var ui: UIViewController { get { return ContentViewController( content: VrComposedView( first: VrLabel( text: ConstString("Please tap:") ), second: VrButton( text: ConstString("OK"), action: ExDoNothing() ) ) ) } } } 

AppDelegate中的用法：

 window?.rootViewController = ScStartScreen().ui 

注意：

• 它遵循面向对象的编码规则（清晰的编码，优雅的对象，装饰模式，…）
• 每个class级都非常简单的build造
• 类通过协议彼此进行通信
• 所有的依赖关系都是通过dependency injection来尽可能的
• 一切（除了结束的业务屏幕）是可重用的 – >事实上：可重复使用的代码组合随着你的代码的增长而增长
• 您的应用程序的业务逻辑集中在Screen对象的实现中
• unit testing非常简单，当使用协议的虚拟实现（甚至在大多数情况下不需要模拟）
• 保留周期较less的问题
• 避免零，零和选项（他们污染你的代码）
• …

在我看来，这是最好的编码方式，但大多数人不这样做。