ios - 如何将变量分离到其他文件并访问

Question

我是 swift 和 IOS 的新手，我不知道将变量(mylessons)分离到其他文件(.swift)或(.json)以实现 MVC。有人可以教我吗？非常感谢

class LessonsTableViewController: UITableViewController {

var mylessons = [["title":"Posture", "subtitle":"Set up your body",
"bgimage":"Ln1", "lesimage":"Posture_pic", "lestitle":"So starting from 
the head and moving down:", "lescontent":"1) The top back part of your 
head should be pointing up.."], ..]

override func viewDidLoad() {
    super.viewDidLoad()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}


override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 150
}

override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}
..
}

Answer 1

引用您给定的代码片段，以实现 MVC ，您应该为 lesson 创建一个模型 - 其中包含所需的属性 - 因此，mylessons 数组应包含 lesson 的对象。 p>

如果您想将不同文件中的层分开(这是一个好主意)，您可能需要创建一个文件 - 例如，Lesson.swift - 其中包含您的模型，如下所示:

Lesson.swift:

// Note that I decalred it as 'struct'
// instead of 'class' do what is suitable
// for your requirements...
struct Lesson {
    var title:String?
    var subtitle: String?
    var bgImage: String?
    var lesImage: String?
    var lesTitle: String?
}

View Controller :

// note that myLessons data type is: '[Lesson]'
var myLessons =  [Lesson(title: "Posture",
                         subtitle: "Set up your body",
                         bgImage: "Ln1",
                         lesImage: "Posture_pic",
                         lesTitle: "So starting from the head and moving down",
                         lesContent: "1) The top back part of your head should be pointing up..")]

备注:如果您正在实现table​View:​cell​For​Row​At​Index​Path:​，您应该像这样访问每一行的类(class):

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    //....

    let currentLesson = myLessons[indexPath.row]

    // ...
}

<小时/>

另外:

如果您能够将给定的字典转换为类(class)对象，那就太好了，实际上这是可能的，通过添加以下字典扩展:

extension Dictionary where Key: ExpressibleByStringLiteral, Value: ExpressibleByStringLiteral {
    func toLesson() -> Lesson {
        var lessonToRetrun = Lesson()

        if let title = self["title"] as? String {
            lessonToRetrun.title = title
        }

        if let subtitle = self["subtitle"] as? String {
            lessonToRetrun.subtitle = subtitle
        }

        if let bgimage = self["bgimage"] as? String {
            lessonToRetrun.bgImage = bgimage
        }

        if let lesimage = self["lesimage"] as? String {
            lessonToRetrun.lesImage = lesimage
        }

        if let lestitle = self["lestitle"] as? String {
            lessonToRetrun.lesTitle = lestitle
        }

        if let lescontent = self["lescontent"] as? String {
            lessonToRetrun.lesContent = lescontent
        }

        return lessonToRetrun
    }
}

你将能够做到:

let lessonDict = ["title":"Posture",
                  "subtitle":"Set up your body",
                  "bgimage":"Ln1", "lesimage":"Posture_pic",
                  "lestitle":"So starting from the head and moving down:",
                  "lescontent":"1) The top back part of your head should be pointing up.."]

let convertedLesson = lessonDict.toLesson()

print(convertedLesson)
// Lesson(title: Optional("Posture"), subtitle: Optional("Set up your body"), bgImage: Optional("Ln1"), lesImage: Optional("Posture_pic"), lesTitle: Optional("So starting from the head and moving down:"), lesContent: Optional("1) The top back part of your head should be pointing up.."))

但您必须非常确定 key 是相同的。

希望这有帮助。