Ios Swift重新加载集合视图不工作

我不熟悉斯威夫特。我遵循一些教程来开发社交应用程序，比如twitter应用程序。我开始执行以下按钮功能。它的调用是另一个API调用，但相同的响应只需稍加修改（例如，follower属性的数量增加一个）。电话也工作得很好。但是集合视图没有重新加载。我的代码是

ViewConroller

import LBTAComponents
import TRON
import SwiftyJSON

class HomeDatasourceController: DatasourceController {

    let errorMessageLabel: UILabel = {
        let label = UILabel()
        label.text = "Apologies something went wrong. Please try again later..."
        label.textAlignment = .center
        label.numberOfLines = 0
        label.isHidden = true
        return label
    }()

    override func willTransition(to newCollection: UITraitCollection, with coordinator: UIViewControllerTransitionCoordinator) {
        collectionViewLayout.invalidateLayout()
    }

    func follow(){
    print("inside controller")
    Service.sharedInstance.fetchfollowHomeFeed { (homeDatasource, err) in
    if let err = err {
        self.errorMessageLabel.isHidden = false

    if let apiError = err as? APIError<Service.JSONError> {

    if apiError.response?.statusCode != 200 {
    self.errorMessageLabel.text = "Status code was not 200"
    }
    }

    return
    }
    self.datasource = homeDatasource
        self.collectionView?.reloadData()
    }
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        view.addSubview(errorMessageLabel)
        errorMessageLabel.fillSuperview() //LBTA method call

        collectionView?.backgroundColor = UIColor(r: 232, g: 236, b: 241)

        setupNavigationBarItems()

        Service.sharedInstance.fetchHomeFeed { (homeDatasource, err) in
            if let err = err {
                self.errorMessageLabel.isHidden = false

                if let apiError = err as? APIError<Service.JSONError> {

                    if apiError.response?.statusCode != 200 {
                        self.errorMessageLabel.text = "Status code was not 200"
                    }
                }

                return
            }

            self.datasource = homeDatasource
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }

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

        //first section of users
        if indexPath.section == 0 {
            guard let user = self.datasource?.item(indexPath) as? User else { return .zero }

            let estimatedHeight = estimatedHeightForText(user.bioText)
            return CGSize(width: view.frame.width, height: estimatedHeight + 66)
        } else if indexPath.section == 1 {
            //our tweets size estimation

            guard let tweet = datasource?.item(indexPath) as? Tweet else { return .zero }

            let estimatedHeight = estimatedHeightForText(tweet.message)

            return CGSize(width: view.frame.width, height: estimatedHeight + 74)
        }


        return CGSize(width: view.frame.width, height: 200)
    }

    private func estimatedHeightForText(_ text: String) -> CGFloat {
        let approximateWidthOfBioTextView = view.frame.width - 12 - 50 - 12 - 2
        let size = CGSize(width: approximateWidthOfBioTextView, height: 1000)
        let attributes = [NSFontAttributeName: UIFont.systemFont(ofSize: 15)]

        let estimatedFrame = NSString(string: text).boundingRect(with: size, options: .usesLineFragmentOrigin, attributes: attributes, context: nil)

        return estimatedFrame.height
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        if section == 1 {
            return .zero
        }
        return CGSize(width: view.frame.width, height: 50)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        if section == 1 {
            return .zero
        }
        return CGSize(width: view.frame.width, height: 64)
    }

}

---

它使用.i尝试了

self.collectionView？.reloadData（）

，但没有重新加载。请帮助我解决此问题。下载我的完整源代码请帮助我

我看到了您的项目并发现了您所做的问题。 在类UserCell.swift中，应使用下一个代码：

func follow(){
    print("inside source")
    guard let link = controller as? HomeDatasourceController else { return }
    link.follow()
}

解释问题

import LBTAComponents
import TRON
import SwiftyJSON

extension Collection where Iterator.Element == JSON {
    func decode<T: JSONDecodable>() throws -> [T] {
        return try map{try T(json: $0)}
    }
}

class HomeDatasource: Datasource, JSONDecodable {

    let users: [User]

    required init(json: JSON) throws {
        guard let usersJsonArray = json["users"].array, let tweetsJsonArray = json["tweets"].array else {
            throw NSError(domain: "com.letsbuildthatapp", code: 1, userInfo: [NSLocalizedDescriptionKey: "Parsing JSON was not valid."])
        }

//        self.users = usersJsonArray.map{User(json: $0)}
//        self.tweets = tweetsJsonArray.map{Tweet(json: $0)}

        self.users = try usersJsonArray.decode()
        self.tweets = try tweetsJsonArray.decode()

    }

    let tweets: [Tweet]

    override func footerClasses() -> [DatasourceCell.Type]? {
        return [UserFooter.self]
    }

    override func headerClasses() -> [DatasourceCell.Type]? {
        return [UserHeader.self]
    }

    override func cellClasses() -> [DatasourceCell.Type] {
        return [UserCell.self, TweetCell.self]
    }

    override func item(_ indexPath: IndexPath) -> Any? {
        if indexPath.section == 1 {
            return tweets[indexPath.item]
        }
        return users[indexPath.item]
    }

    override func numberOfSections() -> Int {
        return 2
    }

    override func numberOfItems(_ section: Int) -> Int {
        if section == 1 {
            return tweets.count
        }
        return users.count
    }

}

这是你项目中的代码

func follow(){
    print("inside source")
    var link = HomeDatasourceController() // in this place you create a new local instance of class 'HomeDatasourceController'
    link.follow()
}

---

您试图在哪里重新加载集合视图？@rmaddy after

self.datasource=homeDatasource

但它没有重新加载查看我的完整代码。您需要在问题中发布相关代码。我共享完整的源代码。您可以通过此链接“”发现预览链接工作不正常，但我假设重新加载的数据代码在异步块之外，因此无法重新加载。正如rmaddy所说，您确实需要在这里发布所有相关代码。

func follow(){
    print("inside source")
    var link = HomeDatasourceController() // in this place you create a new local instance of class 'HomeDatasourceController'
    link.follow()
}