将数据从父 ViewController 传递到子 VC，无需故事板 - Swift 5答案

【问题标题】：Pass data from a Parent ViewController to Child VC without Storyboards - Swift 5将数据从父 ViewController 传递到子 VC，无需故事板 - Swift 5
【发布时间】：2020-03-10 12:53:19
【问题描述】：

一旦我通过 Github API 的 UITextField 获取数据，我就找不到将数据传递给子 VC 的方法

protocol GithubManagerDelegate {
    func didUpdateGithub(_ githubManager: GithubManager, github: GithubModel)
    func didFailWithError(error: Error)
}

struct GithubManager {
    let profileUrl = "https://api.github.com/users"
    let clientId = // deleted this
    let secretId = // deleted this

    var delegate: GithubManagerDelegate?

    func fetchProfile(profileName: String) {
        let urlString = "\(profileUrl)/\(profileName)?client_id=\(clientId)&client_secret=\(secretId)"

        performRequest(with: urlString)
    }


    func performRequest(with urlString: String) {
        if let url = URL(string: urlString) {
            let session = URLSession(configuration: .default)
            let task = session.dataTask(with: url) { (data, response, error) in
                if error != nil {
                    self.delegate?.didFailWithError(error: error!)
                    return
                }

                if let safeData = data {
                    if let github = self.parseJSON(safeData) {
                        self.delegate?.didUpdateGithub(self, github: github)
                        print(github)
                    }
                }
            }
            task.resume()
        }

    }

    func parseJSON(_ githubData: Data) -> GithubModel? {
        let decoder = JSONDecoder()

        do {
            let decodeData = try decoder.decode(GithubData.self, from: githubData)
            let name = decodeData.name ?? "The user does not have a name"
            let login = decodeData.login ?? "No username by this name." // TODO: Change to give a alert
            let avatarUrl = decodeData.avatar_url
            let blog = decodeData.blog ?? "No Blog"
            let bio = decodeData.bio ?? "No Bio"
            let location = decodeData.location ?? "No location"
            let followers = decodeData.followers
            let following = decodeData.following


            let github = GithubModel(githubName: login, githubUser: name, githubAvatar: avatarUrl, githubBio: bio, githubLocation: location, githubBlog: blog, githubFollowers: followers, githubFollowing: following)

            return github

        } catch {
            delegate?.didFailWithError(error: error)
            return nil
        }
    }
}

在 textFieldDidEndEditing 的父 VC 中，我获取输入文本并使用它从 GithubAPI 获取信息

if let username = searchTextField.text {
            DispatchQueue.main.async {
                self.githubManager.fetchProfile(profileName: username)
            }
        }

然后在我的子 VC 中，我使用 GithubManagerDelegate，我在哪里使用 DispatchQueue，用信息填充标签。但是信息是空的，因为一旦收到数据，我就无法将其传递给孩子。

func didUpdateGithub(_ githubManager: GithubManager, github: GithubModel) {
        DispatchQueue.main.async {
            self.usernameLabel.text = github.githubName
        }
    }

我从 ParentVC 到 ChildVC 的方式：

navigationController?.pushViewController(profileVC, animated: true)

希望我让自己清楚问题是什么......

【问题讨论】：

在profileVC中创建一个变量名，在推送profileVC之前设置好

标签： ios swift api viewcontroller

【解决方案1】：

当您尝试在parent ViewController 和child ViewController 之间传递数据时，您应该将子节点添加到子节点而不是导航。

在child 视图控制器中：var passingName: String?

举例

let child = #YourChildViewController insitiate it.
        self.addChild(child)
        child.passingName = passingName
        self.view.addSubview(child.view)
        child.didMove(toParent: self)

希望这个解决方案对你有帮助

【讨论】：