Question

我们希望在单击i.e ImageView内的项目（cell collection）时替换主控制器来显示另一个控制器。但是我们无法获得主集合视图并且无法导航目标控制器。我们正在使用以下方法 -

HomeViewComtroller.swift

import LBTAComponents

class HomeViewController: DatasourceController {

    override func viewDidLoad() {
        super.viewDidLoad()
        navigationItem.title = "Home"
        collectionView?.contentInset = UIEdgeInsetsMake(50, 0, 0, 0)
        collectionView?.scrollIndicatorInsets = UIEdgeInsetsMake(50, 0, 0, 0)
        collectionView?.backgroundColor = UIColor(r: 232, g: 236, b: 241, a: 1)
        let homeViewDatasource = HomeViewDatasource()
        self.datasource = homeViewDatasource
    }


    override func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        if indexPath.section == 0 {
            return CGSize(width: view.frame.width, height: 120)
        } else if indexPath.section == 6 {
            return CGSize(width: view.frame.width, height: 120)
        } else {
             return CGSize(width: view.frame.width, height: 200)
            }


    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
            return CGSize(width: view.frame.width, height: 33)
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        return CGSize(width: view.frame.width, height: 10)
    }


//    lazy var homeMainCatgCell: HomeMainCatgCell = {
//        let homemain = HomeMainCatgCell ()
//        homemain.homeViewcontroller = self
//        return homemain
//    }()


    func handleCtgClick (ctgname: String ,ctgId: String) {

        let dummySettingViewController = UIViewController()
        dummySettingViewController.view.backgroundColor = UIColor.white
        dummySettingViewController.navigationItem.title = ctgname
        navigationController?.navigationBar.tintColor = UIColor.white
        navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
        navigationController?.pushViewController(dummySettingViewController, animated: true)

    }

}

HomeViewDatasource

import LBTAComponents

class HomeViewDatasource: Datasource {

    override func headerClasses() -> [DatasourceCell.Type]? {
         return [HomeMainCatgCellHeader.self,HomeSaleCatgCellHeader.self,HomeNewArrivalCellHeader.self,HomeBestSallingCellHeader.self,HomeBigDiscountCellHeader.self,HomeSpecialOfferCellHeader.self,HomeBrandCellHeader.self]
    }
    override func footerClasses() -> [DatasourceCell.Type]? {
        return[HomeCellsFooter.self]
    }
    override func cellClasses() -> [DatasourceCell.Type] {
        return [HomeMainCatgCell.self,HomeSaleCtagCell.self,HomeNewArrivalsCell.self,HomeBestSallingCatgCell.self,HomeBigDiscountCatgCell.self,HomeSpecialOfferCatgCell.self,HomeBrandVIewCell.self]
    }
    override func numberOfItems(_ section: Int) -> Int {
        return 1
    }
    override func numberOfSections() -> Int {
        return 7
    }
}

HomeMainCatgCell.swift

import LBTAComponents

class HomeMainCatgCell: DatasourceCell {
    var homeViewcontroller: HomeViewController?
    let personalcareCatgImageView: UIImageView = {
        let iv = UIImageView()
        iv.image = #imageLiteral(resourceName: "personalcareimage")
        iv.tag = 0
        iv.contentMode = .scaleToFill
        return iv
    }()

    let healthcareCatgImageView: UIImageView = {
        let iv = UIImageView()
        iv.image = #imageLiteral(resourceName: "healthcareimage")
        iv.contentMode = .scaleToFill
        iv.tag = 1
        return iv
    }()

    let homecareCatgImageView: UIImageView = {
        let iv = UIImageView()
        iv.image = #imageLiteral(resourceName: "homecareimage")
        iv.contentMode = .scaleToFill
        iv.tag = 2
        return iv
    }()

    let kitchencareCatgImageView: UIImageView = {
        let iv = UIImageView()
        iv.image = #imageLiteral(resourceName: "kitchencareiamge")
        iv.contentMode = .scaleToFill
        iv.tag = 3
        return iv
    }()


    override func setupViews() {
        super.setupViews()
        let personalcareCatgImageContainerView = UIView()
        personalcareCatgImageContainerView.backgroundColor = .white

        let homecareCatgImageContainerView = UIView()
        homecareCatgImageContainerView.backgroundColor = .white


        let healthcareCatgImageContainerView = UIView()
        healthcareCatgImageContainerView.backgroundColor = .white


        let kitchencareCatgImageContainerView = UIView()
        kitchencareCatgImageContainerView.backgroundColor = .white


        let imageStackView = UIStackView(arrangedSubviews: [personalcareCatgImageContainerView,homecareCatgImageContainerView,healthcareCatgImageContainerView,kitchencareCatgImageContainerView])
        imageStackView.axis = .horizontal
        imageStackView.distribution = .fillEqually
        addSubview(imageStackView)
        imageStackView.anchor(topAnchor, left: leftAnchor, bottom: self.bottomAnchor, right: self.rightAnchor, topConstant: 0, leftConstant: 0, bottomConstant: 0, rightConstant: 0, widthConstant: frame.width, heightConstant: frame.height)

        imageStackView.addSubview(personalcareCatgImageView)
        imageStackView.addSubview(healthcareCatgImageView)
        imageStackView.addSubview(homecareCatgImageView)
        imageStackView.addSubview(kitchencareCatgImageView)

        personalcareCatgImageView.anchor(personalcareCatgImageContainerView.topAnchor, left: personalcareCatgImageContainerView.leftAnchor, bottom: personalcareCatgImageContainerView.bottomAnchor, right: personalcareCatgImageContainerView.rightAnchor, topConstant: 5, leftConstant: 5, bottomConstant: 5, rightConstant: 5, widthConstant: personalcareCatgImageContainerView.frame.width , heightConstant: personalcareCatgImageContainerView.frame.width)

          healthcareCatgImageView.anchor(healthcareCatgImageContainerView.topAnchor, left: healthcareCatgImageContainerView.leftAnchor, bottom: healthcareCatgImageContainerView.bottomAnchor, right: healthcareCatgImageContainerView.rightAnchor, topConstant: 5, leftConstant: 5, bottomConstant: 5, rightConstant: 5, widthConstant: healthcareCatgImageContainerView.frame.width , heightConstant: healthcareCatgImageContainerView.frame.width)

          homecareCatgImageView.anchor(homecareCatgImageContainerView.topAnchor, left: homecareCatgImageContainerView.leftAnchor, bottom: homecareCatgImageContainerView.bottomAnchor, right: homecareCatgImageContainerView.rightAnchor, topConstant: 5, leftConstant: 5, bottomConstant: 5, rightConstant: 5, widthConstant: homecareCatgImageContainerView.frame.width , heightConstant: homecareCatgImageContainerView.frame.width)

          kitchencareCatgImageView.anchor(kitchencareCatgImageContainerView.topAnchor, left: kitchencareCatgImageContainerView.leftAnchor, bottom: kitchencareCatgImageContainerView.bottomAnchor, right: kitchencareCatgImageContainerView.rightAnchor, topConstant: 5, leftConstant: 5, bottomConstant: 5, rightConstant: 5, widthConstant: kitchencareCatgImageContainerView.frame.width , heightConstant: kitchencareCatgImageContainerView.frame.width)

        personalcareCatgImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleClickCtg)))
        personalcareCatgImageView.isUserInteractionEnabled = true
        healthcareCatgImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleClickCtg)))
        healthcareCatgImageView.isUserInteractionEnabled = true
        homecareCatgImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleClickCtg)))
        homecareCatgImageView.isUserInteractionEnabled = true
        kitchencareCatgImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleClickCtg)))
        kitchencareCatgImageView.isUserInteractionEnabled = true
    }

    func handleClickCtg(gestureRecognizer: UITapGestureRecognizer) {
        var CtgName: String? = nil
        var CtgId: String? = nil
        guard let tag = gestureRecognizer.view?.tag else {return}
        print(tag)
        switch tag {
        case 0:
            CtgName = "Personal Care"
            CtgId = "121"
        case 1:
            CtgName = "Health Care"
            CtgId = "122"
        case 2:
            CtgName = "Home Care"
            CtgId = "123"
        case 3:
            CtgName = "Kitchen Care"
            CtgId = "124"
        default:
            return
        }
        self.homeViewController?.handleCtgClick(ctgname: CtgName! ,ctgId: CtgId!)
    }  
}

主要问题

首先，我没有绑定整个单元格的点击，我只想点击单元格内的ImageView。因此，我在图像视图上绑定GestureRecognizer，如 -

kitchencareCatgImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleClickCtg)))

Click事件可以正常工作，通过print(tag)内部点击功能打印标签（在图片视图中添加）。但是当调用函数self.homeViewcontroller.handleCtgClick(ctgname: CtgName! ,ctgId: CtgId!)（函数存在于HomeViewcontroller类中）时。它没有改变视图控制器。

我还调试了handleCtgClick函数，我发现HomeViewcontroller的对象是nil。

先谢谢

Answer 1

问题是你的＆＃34; homeViewcontroller＆＃34;变量未正确设置。

此代码：

var homeViewcontroller = HomeViewController()

创建HomeViewController类的实例。但是这个实例与您认为的屏幕无关。显示当前视图的屏幕是完全不同的实例。

说实话，你链接一切的方式很奇怪，而且不是很直观。但是如果你想在不改变代码的情况下修复问题，你必须向下传递REAL HomeViewController。

所以在HomeViewController.swift上你有这个代码：

let homeViewDatasource = HomeViewDatasource()
self.datasource = homeViewDatasource

传递＆＃34; handleCtgClick＆＃34;作为它的封闭。

像

这样的东西

homeViewDataSource.presenterClosure = {(ctgname: String ,ctgId: String) in 
        let dummySettingViewController = UIViewController()
        dummySettingViewController.view.backgroundColor = UIColor.white
        dummySettingViewController.navigationItem.title = ctgname
        navigationController?.navigationBar.tintColor = UIColor.white
        navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
        navigationController?.pushViewController(dummySettingViewController, animated: true)
}

（注意，你必须在HomeViewDatasource.swift中创建这个闭包变量声明，以便你可以从HomeViewController.swift中分配它）

然后再次重复此步骤以将其传递给HomeMainCatgCell.swift

然后，您将能够引用此函数引用您创建的本地闭包变量。

可替换地：

您只需将引用传递给HomeViewController本身即可。但是如果你决定这样做，请确保你继续作为＆＃34;可选＆＃34;变量与＆＃34;弱＆＃34;属性或您将创建一个保留循环。

Answer 2

如果在单元类中声明控制器的全局实例，则会创建引用周期并在应用中创建泄漏。您的单元格将强烈引用您的控制器，您的控制器将强烈引用您的tableview，这反过来保持对单元格的强引用，其次您可能无法告诉单击单元格的索引路径允许编辑。您可以尝试以下方法来克服这两个问题。

首先在您的单元格类中创建一个枚举，根据您的图像视图命名案例，以便您的控制器知道单击了哪个图像视图，您也可以将标记链接到它。类似的东西：

enum CategoryViews:Int{
    case personal = 0,healthcare = 1,homecare = 2,kitchencare = 3
}

然后在您的单元格类中创建一个协议，如：

protocol HomeMainCatgCellDelegate:class{
   func clicked(view:CategoryViews,forCell cell:HomeMainCatgCell)
}

然后在您的单元类中创建一个弱变量，并在您的动作处理程序方法中调用协议方法

class HomeMainCatgCell: DatasourceCell {
     weak var delegate:HomeMainCatgCellDelegate?
     //Remove the variable var homeViewcontroller: HomeViewController? to avoid reference cycle and we don't need it anyway.
 ...
func handleClickCtg(gestureRecognizer: UITapGestureRecognizer) {
    guard let tag = gestureRecognizer.view?.tag else {return}
    print(tag)
    if let clickedImageView = CategoryViews(rawValue:tag){
        self.delegate?.clicked(view:clickedImageView,forCell:self)
    }
}  
}

然后在您的视图控制器类中，您必须确认HomeMainCatgCellDelegate协议并将单元格的委托设置为self。

class HomeViewController: DatasourceController, HomeMainCatgCellDelegate{
...
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
//Dequeue your cell here
 cell.delegate = self
 ...
 return self
}
func clicked(view:CategoryViews,forCell cell:HomeMainCatgCell){
    //And you can handle your events accordingly here
    if let indexpath = self.collectionView.indexPath(for: cell){
    //Here you will get the indexpath of clicked cell and then you can put a switch condition to check which imageview is clicked
          switch view{
          case .personal:break
          case .healthcare:break
          case .homecare:break
          case .kitchencare:break
          }
    }
}
}

希望这有帮助。

单击collectionView单元格内的项目时如何导航另一个视图控制器使用Swift 3

2 个答案: