如何在 Swift UIKit 的 if 语句中显示多个警报？

Question

    func submit(_ answer: String) {
        let lowerAnswer = answer.lowercased()
        
        if answer.count == 0 {
            showErrorMessage(errorTitle: "No answer", errorMessage: "Please provide a valid answer")
            return
        }
        
        if isPossible(word: lowerAnswer) {
            if isOriginal(word: lowerAnswer) {
                if isReal(word: lowerAnswer) {
                    userWords.insert(answer, at: 0)
                    
                    let indexPath = IndexPath(row: 0, section: 0)
                    tableView.insertRows(at: [indexPath], with: .automatic)
                    
                    return
                }
                
                showErrorMessage(errorTitle: "Word not recognised", errorMessage: "You can't just make them up, you know!")
                return
            }
            
            showErrorMessage(errorTitle: "This word is already used!", errorMessage: "New word is required!")
            return
        }
        
        guard let title = title?.lowercased() else { return }
        showErrorMessage(errorTitle: "Word not possible", errorMessage: "You can't spell that word from \(title)")
        return
    }
    
    func isPossible(word: String) -> Bool { // Will check if the user is able to formuate a word
        guard var tempWord = title?.lowercased() else { return false }
        
        for letter in word { // Loops through the word provided by the player by checking and adding each letter to "letter" loop constant [This will contain all the letter from that word]
            
            if let positon = tempWord.firstIndex(of: letter) { // Checks if the player's word comtains letters from the start word [from what the player need to create a new word]
                tempWord.remove(at: positon) // Removes the used letter from the start word, that letter will not exist anymore so the player will not be able to use it twice
            } else {
                return false
            }
        }
        
        return true
    }
    
    func isOriginal(word: String) -> Bool { // Will check for duplicate words if any
        return !userWords.contains(word) // If the word is new this method will return "true", if the word was used before this method will return "false"
    }
    
    func isReal(word: String) -> Bool { // Will check is the word is a real word [english]
        let checker = UITextChecker()
        let range = NSRange(location: 0, length: word.utf16.count)
        let misspelledRange = checker.rangeOfMisspelledWord(in: word, range: range, startingAt: 0, wrap: false, language: "en")
        
        
        if word.utf16.count < 3 {
            showErrorMessage(errorTitle: "Word to short", errorMessage: "Please provide a longer word")
            print("This word is to short!")
            return false
            
        } else if title?.utf16.count == word.utf16.count {
            // showErrorMessage(errorTitle: "Invalid answer", errorMessage: "You cannot submit the start word!")
            print("You can't submit the start word!")
            return false
        }
        
        return misspelledRange.location == NSNotFound // if misspelledRange.location == NSNotFound [true = not a valid word]; if misspelledRange.location == NSNotFound [false = we have a valid word        
    }
    
    func showErrorMessage(errorTitle: String, errorMessage: String) {
        let alert = UIAlertController(title: errorTitle, message: errorMessage, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default))
        present(alert, animated: true)
    }
}

如何在“isReal”if 语句中显示 3 个警报？
我试过了，调试控制台告诉我这个：

2021-04-05 23:25:37.577297+0100 Project5[4940:314069] [Presentation] Attempt to present on (from 。

Answer 1

你可以用这样的扩展来做到这一点：

extension UIViewController {
    static func top() -> UIViewController {
        guard let rootViewController = UIApplication.shared.delegate?.window??.rootViewController else { fatalError("No view controller present in app?") }
        var result = rootViewController
        while let vc = result.presentedViewController, !vc.isBeingDismissed {
            result = vc
        }
        return result
    }
}

然后，您可以打电话给UIViewController.top().present(alert, animated: true)，而不是只打电话给present(alert, animated: true)。 这将导致每个附加警报出现在前一个警报之上。用户必须先关闭所有三个警报，然后才能返回您的屏幕。

---

以上回答了您的问题，但我希望一旦您了解用户不得不关闭多个警报的情况后，您将重新考虑您的设计，而是针对所有问题提供一个带有适当文本的警报。或者找一些其他的 UI 来处理这个问题。