集合视图单元格导航

Question

亲爱的程序员，请帮助我。我 2 个月前开始学习 Swift，如果我能完成的话，这将是我的第一个应用程序...... 首先，我不使用情节提要。在我的应用程序中，主窗口中有集合视图。当您点击单元格中的图像时，例如猫单元格中的猫图像，Cat.swift 文件应该打开。但我还不能实现它。同样，如果您点击狗图像，应该会查看 Dog.swift 文件。这是代码。

这是您打开应用程序时的主屏幕：

import UIKit

class FeaturedAnimalsController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    var animalCategories: [AnimalCategory]?

    private let cellId = "cellId"

    override func viewDidLoad() {
        super.viewDidLoad()

        animalCategories = AnimalCategory.sampleAnimalCategories()

        collectionView?.backgroundColor = .white
        collectionView?.register(CategoryCell.self, forCellWithReuseIdentifier: cellId)
    }

    func showAnimalDetailForAnimal(animal: Animal) {
        let layout = UICollectionViewFlowLayout()
        let animalDetailController = AnimalDetailController(collectionViewLayout: layout)
        animalDetailController.animal = animal
        navigationController?.pushViewController(animalDetailController, animated: true)
    }


    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if let count = animalCategories?.count {
            return count
        }
        return 0
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! CategoryCell

        cell.featuredAnimalsController = self

        cell.animalCategory = animalCategories?[indexPath.item]

        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: view.frame.width, height: 230)
    }

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

这是 CategoryCell：

import UIKit

class CategoryCell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

    var featuredAnimalsController: FeaturedAnimalsController?

    var animalCategory: AnimalCategory? {
        didSet {
            if let name = animalCategory?.name {
                nameLabel.text = name
            }
        }
    }

    private let cellId = "animalCellId"

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if let count = animalCategory?.animals?.count {
            return count
        }
        return 0
    }


    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! AnimalCell
        cell.animal = animalCategory?.animals?[indexPath.item]
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: 100, height: frame.height - 32)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: 0, left: 14, bottom: 0, right: 14)
    }

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        if let animal = animalCategory?.animals![indexPath.item] {
            featuredAnimalsController?.showAnimalDetailForAnimal(animal: animal)
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        setupViews()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    let nameLabel: UILabel = {
        let label = UILabel()
        label.text = "Cardiology"
        label.font = UIFont.systemFont(ofSize: 16)
        //label.numberOfLines = 1  --> DEFAULT
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    let animalsCollectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
        collectionView.backgroundColor = .clear
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        return collectionView
    }()

    func setupViews() {
        backgroundColor = .clear

        animalsCollectionView.dataSource = self
        animalsCollectionView.delegate = self

        animalsCollectionView.register(AnimalCell.self, forCellWithReuseIdentifier: cellId)


        addSubview(nameLabel)
        addSubview(animalsCollectionView)

        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-14-[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": animalsCollectionView]))
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[nameLabel(30)][v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": animalsCollectionView, "nameLabel": nameLabel]))

    }


}

class AnimalCell: UICollectionViewCell {

    var animal: Animal? {
        didSet {
            if let name = animal?.name {
                nameLabel.text = name
            }
            categoryLabel.text = animal?.category

            if let imageName = animal?.imageName {
                imageView.image = UIImage(named: imageName)
            }
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        setupViews()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func setupViews() {
        backgroundColor = .clear

        addSubview(categoryLabel)
        addSubview(imageView)
        addSubview(nameLabel)

        categoryLabel.frame = CGRect(x: 0, y: frame.width + 38, width: frame.width, height: 20)
        imageView.frame = CGRect(x: 0, y: 0, width: frame.width, height: frame.width)
        nameLabel.frame = CGRect(x: 0, y: frame.width + 2, width: frame.width, height: 40)

    }

    let imageView: UIImageView = {
        let iv = UIImageView()
        //iv.image = UIImage(named: "cat")
        iv.contentMode = .scaleAspectFill
        iv.translatesAutoresizingMaskIntoConstraints = false
        iv.layer.cornerRadius = 16
        iv.layer.masksToBounds = true
        return iv
    }()

    let nameLabel: UILabel = {
        let label = UILabel()
        label.text = ""
        label.font = UIFont.systemFont(ofSize: 14)
        label.numberOfLines = 2
        return label
    }()

    let categoryLabel: UILabel = {
        let label = UILabel()
        label.text = ""
        label.font = UIFont.systemFont(ofSize: 13)
        label.numberOfLines = 2
        return label
    }()  
}

这是动物类别模型：

import UIKit

class AnimalCategory: NSObject {

    var name: String?
    var animals: [Animal]?

    static func sampleAnimalCategories() -> [AnimalCategory] {


        let catFamilyCategory = AnimalCategory()
        catFamilyCategory.name = "Cat Family"
        var catFamilyAnimals = [Animal]()

        let catAnimal = Animal()
        catAnimal.name = "Cat"
        catAnimal.imageName = "cat"
        catAnimal.category = "Lovely"
        //catAnimal.dvcName = Cat.self()
        catFamilyAnimals.append(catAnimal)

        catFamilyCategory.animals = catFamilyAnimals



        let dogFamilyCategory = AnimalCategory()
        dogFamilyCategory.name = "Dog Family"
        var dogFamilyAnimals = [Animal]()

        let dogAnimal = Animal()
        dogAnimal.name = "Dog"
        dogAnimal.imageName = "dog"
        dogAnimal.category = "Friendly"
        //dogAnimal.dvcName = Dog.self
        dogFamilyAnimals.append(dogAnimal)

        dogFamilyCategory.animals = dogFamilyAnimals


        return [catFamilyCategory, dogFamilyCategory]
    }
}

这是动物模型：

import UIKit

class Animal: NSObject {

    //var id: NSNumber?
    var name: String?
    var category: String?
    var imageName: String?
    //var dvc: AnimalDetailController?

}

这是动物细节控制器和示例 cat.swift：

import UIKit

class AnimalDetailController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    var animal: Animal? {
        didSet {
            navigationItem.title = animal?.name
        }
    }
}

class Cat: AnimalDetailController {
    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .brown
    }
}

感谢@Paulw11，在进行了一些更改后，这里是为每个动物呈现特定细节视图控制器的代码：

func showAnimalDetailFor(_ animal: Animal) {
        let layout = UICollectionViewFlowLayout()

        var dvc = animal.dvc
        dvc = AnimalDetailController(collectionViewLayout: layout)
        self.show(dvc, sender: self)
    }

这里是动物和动物类别模型：

struct Animal {

    let name: String
    let category: String
    let imageName: String
    let dvc: AnimalDetailController

}

struct AnimalCategory {

    var name: String
    private var _animals = [Animal]()

    var animals: [Animal] {
        get {
            return self._animals
        }
    }

    init(name: String) {
        self.name = name
    }

    static var sampleAnimalCategories: [AnimalCategory] = {

        var dogFamily = AnimalCategory(name: "Dog Family")
        dogFamily.addAnimal(Animal(name: "Dog", category: "Friendly", imageName: "dog", dvc: DogDetailViewController()))

        var catFamily = AnimalCategory(name: "Cat Family")
        catFamily.addAnimal(Animal(name: "Cat", category: "Lovely", imageName: "cat", dvc: CatDetailViewController()))

        let categories = [dogFamily,catFamily]
        return categories
    }()

    mutating func addAnimal(_ animal: Animal) {
        self._animals.append(animal)
    }

}

和动物细节控制器类：

class AnimalDetailController: UICollectionViewController, UICollectionViewDelegateFlowLayout {


    var animal: Animal? {
        didSet {
            navigationItem.title = animal?.name
        }
    }
}

我不会在视图控制器之间传输数据。我计划为牢房中的每只动物制作特定的 swift 文件，然后当你点击它们的图标时，我希望这些 swift 文件显示出来。当然，我正在使用导航控制器并将其设置在应用程序委托中。

请帮助我。谢谢大家。

Answer 1

一般来说，我会提醒不要将数据和代码紧密耦合，但是您可以通过在数据模型中存储对视图控制器类的引用来做您想做的事情；您在注释代码中几乎是正确的；你只是不需要() 在self 之后。

如果您不需要可变性，最好使用结构，因此您的Animal 和AnimalCategory 对象可以是结构。您也可以避免所有这些选项。

struct Animal {
    let name: String
    let category: String
    let imageName: String
    let dvc: AnimalDetailController.Type
}

struct AnimalCategory {

    var name: String

    private var _animals = [Animal]()

    var animals: [Animal] {
        get {
            return self._animals
        }
    }

    init(name: String) {
        self.name = name
    }

    static var sampleAnimalCategories: [AnimalCategory] = {

        var dogs = AnimalCategory(name: "Dog Family")
        dogs.addAnimal(Animal(name: "Dog", category: "Friendly", imageName: "dog", dvc: DogDetailViewController.self))

        var cats = AnimalCategory(name: "Cat Family")
        cats.addAnimal(Animal(name: "Cat", category: "Lovely", imageName: "cat", dvc: CatDetailViewController.self))

        let categories = [dogs,cats]
        return categories
    }()

    mutating func addAnimal(_ animal: Animal) {
        self._animals.append(animal)
    }

}

那么您的showAnimalDetailForAnimal 将类似于：

func showAnimalDetailFor(_ animal: Animal) {
    let dvc = animal.dvc.init() 
    self.show(dvc, sender: self)
}

您还可以在使用选项方面做很多清理工作。例如，animals 和 animalCategories 都可以是隐式展开的可选项。

您将无法拥有您的AnimalDetailViewController 子类UICollectionViewController，因为您无法使用布局进行初始化。您需要继承 UIViewController 并将集合视图添加到您的 viewDidLoad