ios - TableView Controller 的按钮并执行过滤功能

Question

请原谅我是一个新程序员，对编码不熟悉所以我的问题是我想在 Viewcontroller1 中创建一个按钮，它触发操作转到另一个 View Controller (我做到了)，并同时调用 TutorListTableViewController (在另一个类中)的函数(过滤 TableView )

我不确定调用另一个类的函数是否是正确的方法。如果是的话，我仍然无法成功调用该函数。任何帮助深表感谢!错误显示如下:

ViewController1 的按钮操作

@IBAction func englishGO(_ sender: Any) {
    self.tabBarController?.selectedIndex = 1
    TutorListViewController.observeEnglishCases()
}

TutorListTableViewController的功能

func observeEnglishCases(){
    let casesRef = Database.database().reference().child("cases")
    let queryRef = casesRef.child("school").queryEqual(toValue: "Ling")
    queryRef.observe(.value, with: { snapshot in

        var tempPosts = [Case]()


        for child in snapshot.children {
            if let childSnapshot = child as? DataSnapshot,
                let dict = childSnapshot.value as? [String:Any],
                let name = dict["name"] as? String,
                let gender = dict["gender"] as? String,
                let school = dict["school"] as? String,
                let year = dict["year"] as? String,
                let major = dict["major"] as? String,
                let tutorsubject = dict["tutorsubject"] as? String,
                let tutoryear = dict["tutoryear"] as? String,
                let tutorperformance = dict["tutorperformance"] as? String,
                let region = dict["region"] as? String,
                let minimumprice = dict["minimumprice"] as? String,
                let thingtospeak = dict["thingtospeak"] as? String,
                let photoURL = dict["photoURL"] as? String,
                let url = URL(string:photoURL){
                let caser = Case(name: name, gender: gender, school: school, year: year, major: major, tutorsubject: tutorsubject, tutoryear: tutoryear, tutorperformance: tutorperformance, region: region, minimumprice: minimumprice, thingtospeak: thingtospeak, photoURL: url)
                tempPosts.insert(caser, at:0)
            }
        }
        self.cases = tempPosts
        self.tutorCasesCollectionView.reloadData()
    })

}

Answer 1

正如已经指出的，您需要阅读如何传递信息。 (委托(delegate)、通知、 block )为您提供稍后的总体思路:

• ViewController1 可以有一个委托(delegate)来告诉某人“englishGO”已被点击
• 某人必须引用 TutorListViewController 实例，并且当检测到“englishGO”点击时，它会在该实例上调用 observeEnglishCases()

但是，在您当前的实现中，这可能有效:

@IBAction func englishGO(_ sender: Any) {
    self.tabBarController?.selectedIndex = 1
    (self.tabBarController.viewControllers[1] as? TutorListViewController)?. observeEnglishCases()
}

observeEnglishCases() 是一个实例方法，必须这样调用。通过编写 TutorListViewController.observeEnglishCases()，您调用了一个类方法，该方法可能在您的代码中不存在。