Question

我有一个莫名其妙的情况，我将变量passageText设置为某个值，但它不会更新UITextView。

这是我的控制器代码：

import UIKit
import CoreData

class FavoritesDetailsViewController: UIViewController, UITextViewDelegate {

@IBOutlet weak var referenceLabel: UILabel!

//I've confirmed that the UITextView is connected to this outlet
@IBOutlet weak var passageText: UITextView!

var specifiedFavorite : String = ""

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    referenceLabel.text? = specifiedFavorite

    print("The FavoritesDetailsViewController viewDidLoad")

    print("The Value of variable specifiedFavorite sent from segue is: \(specifiedFavorite)")

    let appDelegate = UIApplication.shared.delegate as! AppDelegate

    let context = appDelegate.persistentContainer.viewContext

    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Passages")

    request.predicate = NSPredicate(format: "reference == %@", specifiedFavorite)

    request.returnsObjectsAsFaults = false

    do {

        let results = try context.fetch(request)

        print("fetch request was successful")

        if results.count > 0 {

            print("The number of results returned is: \(results.count)")

            for result in results as! [NSManagedObject] {

                print("We got results!")

                if let returnedText = result.value(forKey: "passagetext") as? String {

                    self.passageText.text! = returnedText

                    print("This is the text from the passageText textview: \(self.passageText.text!)")

                }

            }

        }

    } catch {

        print("Couldn't fetch results")

    }    
}

override func viewDidLoad() {
    super.viewDidLoad()

    print("The FavoritesDetailsViewController viewDidLoad")

    print("The Value of variable specifiedFavorite sent from segue is: \(specifiedFavorite)")

    print(specifiedFavorite)
}
}

以下是我的日志输出：

The Value of variable specifiedFavorite sent from segue is: Genesis 3:1
fetch request was successful
The number of results returned is: 1
We got results!
This is the text from the passageText textview: The Fall
Now  the serpent was more crafty than any other beast....

所以看来UITextView文本名为＆＃34; passageText＆＃34;已经设置得当。

self.passageText.text! = returnedText

我知道无法添加.text通常是一个新手错误，我想我在这里避免了。我还确认UITextView已连接到我的IBOutlet。我不确定为什么用户界面没有更新到新值。我可以用一些新鲜的眼睛。

Answer 1

好吧，我会把这个白垩体验起来。问题是我的自动布局约束设置不正确，因此UITextView在UI中不可见。这很容易被忽略，因为在Xcode中，textview是可见的。但是不要忽视那些红线和Xcode警告！它们表明即使应用程序编译和运行也会影响正常功能的问题。希望有人从我的错误中学习。

变量不设置textview文本

1 个答案: