UICollectionView 以编程方式

Question

我在故事板中创建了自己的 window，如下所示：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.makeKeyAndVisible()
        window?.rootViewController = UINavigationController(rootViewController: HomeController())
        return true
    }

当我的 class 是 UIViewController 的子class 时，这实际上工作正常。

class HomeController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        view.backgroundColor = UIColor.red
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

现在当我用 UICollectionViewController 子class 我的 class:

class HomeController: UICollectionViewController {

        override func viewDidLoad() {
            super.viewDidLoad()
            // Do any additional setup after loading the view, typically from a nib.
            Collectionview.backgroundColor = UIColor.red
        }

        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
            // Dispose of any resources that can be recreated.
        }


    }

在运行时它给我一个错误提示：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'UICollectionView must be initialized with a non-nil layout parameter' *** First throw call stack:

据我所知，它要求我为 UICollectionView 提供布局。如果我是 wrong.So，请在此处更正我，我试过这个-:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.makeKeyAndVisible()
        let layout = UICollectionViewFlowLayout()
        window?.rootViewController = UINavigationController(rootViewController: HomeController(UICollectionViewLayout: layout))
        return true
    }

但仍然以错误结束：

Argument labels 'UICollectionViewLayout' do not match any available overloads.

我是否使用了错误的 swift3 语法？如果是，解决这个问题的正确方法是什么。

Answer 1

您需要在 UICollectionViewController 中实施 UICollectionViewFlowLayout。

勾选这个Link

您必须使用 initWithFrame:collectionViewLayout: 来初始化您的 UICollectionView 并且您必须传递一个非零值 UICollectionViewLayout object。

Answer 2

您需要使用 UICollectionViewController 的指定初始化器，如下所示。

let layout = UICollectionViewLayout()
let homeViewController = HomeController(collectionViewLayout: layout)
window?.rootViewController = UINavigationController(rootViewController: homeViewController)

除此之外，您还需要修改 HomeViewController 以实现 UICollectionViewDataSource 所需的方法。

override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Register cell classes
        self.collectionView!.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")

        // Do any additional setup after loading the view.
    }


// MARK: UICollectionViewDataSource

    override func numberOfSections(in collectionView: UICollectionView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 0
    }


    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of items
        return 0
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)

        // Configure the cell

        return cell
    }

UICollectionView 以编程方式

UICollectionView Programmatically

ios

uicollectionview

swift

swift2

swift3