ios - MVVM UITableViewCell 返回 nil

Question

我正在尝试在 UITableViewController 上进行 MVVM 集成，但是我不断收到:

fatal error :在 super.init(style:style，reuseIdentifier:reuseIdentifier) 上解包可选值时意外发现 nil。

怎么会呢？我想这与以下内容有关:

cell.menuItemViewModel = SideMenuViewModel(menuItem: item)

如果我删除这一行就不会出现错误？

在sideMenuController中设置数据源

func setupDatasource() {

    let sections = [
        SectionModel(model: "menu", items: menuItems)
    ]

    dataSource.configureCell = { (ds, tv, ip, item) in
        let cell: MenuCell = tv.dequeueReusableCell(withIdentifier: self.reuseIdentifier, for: ip) as! MenuCell
        cell.menuItemViewModel = SideMenuViewModel(menuItem: item)


        return cell
    }


    Observable.just(sections)
        .bindTo(tableView.rx.items(dataSource: dataSource))
        .addDisposableTo(disposeBag)
}

菜单项模型

struct MenuItem {

    var title: String
    var image: Asset
    var imageSelected: Asset
    var controller: UINavigationController

    init(title: String, image: Asset, imageSelected: Asset, controller: UINavigationController) {
        self.title = title
        self.image = image
        self.imageSelected = imageSelected
        self.controller = controller
    }


}

View 模型

struct SideMenuViewModel {

    let title: String
    let image: UIImage
    let imageSelected: UIImage


    init(menuItem: MenuItem) {
        self.title = menuItem.title
        self.image = UIImage(asset: menuItem.image)
        self.imageSelected = UIImage(asset: menuItem.imageSelected)
    }

}

菜单单元格

class MenuCell: UITableViewCell {

    var titleLabel: UILabel!
    var iconImageView: UIImageView!

    var menuItemViewModel: SideMenuViewModel! {
        didSet {
            //Set title
            self.titleLabel.text = menuItemViewModel.title

            //Set image
            self.iconImageView.image = menuItemViewModel.image

        }
    }


    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)


        setupUI()
        setupConstraints()

    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    func setupUI() {

        //Add titleLabel
        self.titleLabel = UILabel()
        self.addSubview(self.titleLabel)

        //Add iconImageView
        self.iconImageView = UIImageView()
        self.addSubview(self.iconImageView)

        //Customize titleLabel
        self.titleLabel.font = FontFamily.Avenir.Regular.font(size: 26)
        self.titleLabel.textColor = UIColor.white.withAlphaComponent(0.6)

        //Customize iconImageView
        self.iconImageView.contentMode = .scaleAspectFit

        //Customize cell
        self.selectionStyle = .none
        self.backgroundColor = UIColor.clear
    }

    func setupConstraints() {

        //titleLabel constraints
        self.titleLabel.snp.makeConstraints({ make in
            make.left.equalTo(self.iconImageView.snp.right).offset(-20)
            make.centerY.equalTo(self)
            make.height.equalTo(50)
            make.width.equalTo(100)
        })

        //iconImageView constraints
        self.iconImageView.snp.makeConstraints({ make in
            make.left.equalTo(80)
            make.centerY.equalTo(self)
            make.height.equalTo(50)
            make.width.equalTo(50)
            make.right.equalTo(self.titleLabel.snp.left).offset(20)
        })

    }


}

Answer 1

你注册了手机吗？

tableView.register(MenuCell, forCellReuseIdentifier: self.reuseIdentifier)

如果使用 Storyboard 将类添加到单元格中，则无需注册它，也不应该注册。

此外，当您使用错误的 reuseIdentifier 时，也可能会发生错误。