ios - swift:在 awakeFromNib() 中展开可选值时意外发现 nil

Question

我可能只是错过了一些东西，但对于我来说，我想不通。

我正在开发一个具有 MVC 结构的应用程序；我将所有需要的字段放在 Xib 上，但我依赖 View 来实际更改字体、大小等。

这是我的代码:

import Foundation
import UIKit

protocol ProductionWellChemistryFormTwoViewDelegate {

}

class ProductionWellChemistryFormTwoView: BaseUIView {

    let fontSizeL : CGFloat = 18
    let fontName : String = "Futura"
    var delegate : ProductionWellChemistryFormTwoViewDelegate!

    @IBOutlet weak var labelTitle: UILabel!
    @IBOutlet weak var labelFieldCode: UILabel!
    @IBOutlet weak var labelGasFlaskNo: UILabel!
    @IBOutlet weak var labelDatePrepared: UILabel!
    @IBOutlet weak var labelDateVacuumed: UILabel!
    @IBOutlet weak var labelClickingSound: UILabel!
    @IBOutlet weak var labelTimeStarted: UILabel!
    @IBOutlet weak var labelTimeFinished: UILabel!
    @IBOutlet weak var labelWHPStarted: UILabel!
    @IBOutlet weak var labelWHPEnded: UILabel!
    @IBOutlet weak var labelSPPStarted: UILabel!
    @IBOutlet weak var labelSPPEnded: UILabel!
    @IBOutlet weak var labelSPStarted: UILabel!
    @IBOutlet weak var labelSPEnded: UILabel!
    @IBOutlet weak var labelRemarks: UILabel!

    @IBOutlet weak var textfieldFieldCode: UITextField!
    @IBOutlet weak var textfieldGasFlaskNo: UITextField!
    @IBOutlet weak var textfieldDatePrepared: UITextField!
    @IBOutlet weak var textfieldDateVacuumed: UITextField!
    @IBOutlet weak var textfieldTimeStarted: UITextField!
    @IBOutlet weak var textfieldTimeFinished: UITextField!
    @IBOutlet weak var textfieldWHPStarted: UITextField!
    @IBOutlet weak var textfieldWHPEnded: UITextField!
    @IBOutlet weak var textfieldSPPStarted: UITextField!
    @IBOutlet weak var textfieldSPPEnded: UITextField!
    @IBOutlet weak var textfieldSPStarted: UITextField!
    @IBOutlet weak var textfieldSPEnded: UITextField!
    @IBOutlet weak var textviewRemarks: UITextView!

    @IBOutlet weak var switchClickSound: UISwitch!

    override func awakeFromNib() {
        self.labelTitle.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelFieldCode.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelGasFlaskNo.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelDatePrepared.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelDateVacuumed.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelClickingSound.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelTimeStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelTimeFinished.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelWHPStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelWHPEnded.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelSPPStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelSPPEnded.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelSPStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelSPEnded.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.labelRemarks.font = UIFont(name: self.fontName, size: self.fontSizeL)

        self.textfieldFieldCode.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldGasFlaskNo.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldDatePrepared.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldDateVacuumed.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldTimeStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldTimeFinished.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldWHPStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldWHPEnded.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldSPPStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldSPPEnded.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldSPStarted.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textfieldSPEnded.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textviewRemarks.font = UIFont(name: self.fontName, size: self.fontSizeL)
        self.textviewRemarks.layer.borderWidth = 1.0
        self.textviewRemarks.layer.borderColor = UIColor.blackColor().CGColor
        self.textviewRemarks.text = ""
    }
}

当我读取 awakeFromNib() 的第一行时，代码抛出异常，无论那是什么(我尝试注释掉第一行，所以它转到了第二行)。

我总共这样做了十几次，所以我真的不确定发生了什么。我唯一能想到的不同之处是尝试通过进入 Xib 的源代码并重命名类 ProductionWellChemistryFormTwoViewer 来修复以前的 Interface Builder 文件中的未知类，一个错误命名的类，然后我现在将其重命名为我的类(没有过去的 View )。

如果我禁用 awakeFromNib() 中的所有内容，应用程序就会运行。

编辑:如果我更改 XIB 源代码中的以下行，该应用程序也可以正常运行，包括字体和所有内容:

<view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="vYc-5l-gfD" userLabel="ContentView" customClass="ProductionWellChemistryFormTwoView" customModule="Integra_Geochemistry" customModuleProvider="target">

回到:

<view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="vYc-5l-gfD" userLabel="ContentView" customClass="ProductionWellChemistryFormTwoViewer"  customModule="Integra_Geochemistry" customModuleProvider="target">

我在 Interface Builder 文件中得到一个 Unknown class _TtC20Integra_Geochemistry36ProductionWellChemistryFormTwoViewer。 错误，但至少它有效。

我将扩展我上面提到的情况，这是发生的事情:

1. 我创建了 XIB。
2. 我创建了 View ，错误地命名为 ProductionWellChemistryFormTwoViewer
3. 将 XIB 的类设置为所述 View 。
4. 发现错误的名字。
5. 将名称更改为 ProductionWellChemistryFormTwoView。弹出一些错误。
6. 手动将对 ProductionWellChemistryFormTwoViewer 的任何引用更改为 ProductionWellChemistryFormTwoView。
7. 注意到运行该应用会产生未知类错误，进入 XIB 源代码，删除 ProductionWellChemistryFormTwoViewer。
8. 然后我得到了上面的错误。

Answer 1

所以很可能您没有链接其中一个 IBOutlets。

有那么多的网点，要找出哪个网点会让人感到困惑，所以我建议您采纳@originaluser2 的建议并使用 IBCollections。

class ProductionWellChemistryFormTwoView: BaseUIView {
    let fontSizeL : CGFloat = 18
    let fontName : String = "Futura"
    var delegate : ProductionWellChemistryFormTwoViewDelegate!

    // By declaring the IBOutlet as an array it tells IB that its a collection
    @IBOutlet var labelCollection: [UILabel]! 
    @IBOutlet var textFieldCollection: [UITextField]!  

    @IBOutlet weak var textviewRemarks: UITextView!

    override func awakeFromNib() {
        let font = UIFont(name: self.fontName, size: self.fontSizeL)
        labelCollection.each{ $0.font = font }
        textFieldCollection.each{ $0.font = font }

        textviewRemarks.layer.borderWidth = 1.0
        textviewRemarks.layer.borderColor = UIColor.blackColor().CGColor
        textviewRemarks.text = ""
    }   
}

然后通过您的 xib 并根据需要连接所有 socket 。