Swift 3 viewDidLoad（） - 致命錯誤：意外地發現零，同時展開一個可選值

我已經嘗試了所有以前的建議來解決這個問題，但仍然沒有運氣。它正在工作（UIPickerView正確填充），但現在應用程序崩潰後viewDidLoad（）運行。已驗證所有IBOutlet已正確連接。嘗試重新創建可可觸摸文件。Swift 3 viewDidLoad（） - 致命錯誤：意外地發現零，同時展開一個可選值

這是我的視圖控制器代碼。這應該是我忽視的一些小事。幫幫我！！

class SettingsVC: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate { 

@IBOutlet weak var targetCadenceLabel: UILabel? 
@IBOutlet weak var cadenceStepper: UIStepper? 
@IBOutlet weak var goalPicker: UIPickerView? 

var pickerDataSource = ["improve SPM", "maintain SPM"] 

override func viewDidLoad() { 
    super.viewDidLoad() 
    self.goalPicker?.dataSource = self 
    self.goalPicker?.delegate = self 


    //MARK: Setup Tab Bar 
    let tabBarItem = self.tabBarItem 
    let incomingSelectedImage: UIImage! = UIImage(named: "settings_icon")?.withRenderingMode(.alwaysOriginal) 
    tabBarItem?.selectedImage = incomingSelectedImage 
    tabBarItem?.setTitleTextAttributes([NSForegroundColorAttributeName : UIColor(red: 60/255, green: 159/255, blue: 255/255, alpha: 1.0)], for: UIControlState.selected) 
} 


//MARK: - Delegates and data sources 
//MARK: Data Sources 
func numberOfComponents(in pickerView: UIPickerView) -> Int { 
    return 1 
} 

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int { 
    return pickerDataSource.count 
} 

//MARK: Delegates 
func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? { 
    let titleData = pickerDataSource[row] 
    let myFont = UIFont.systemFont(ofSize: 18) 
    let fontColor = UIColor(red: 60/255, green: 159/255, blue: 255/255, alpha: 1.0) 
    let myTitle = NSAttributedString(string: titleData, attributes: [NSFontAttributeName: myFont,NSForegroundColorAttributeName:fontColor]) 
    return myTitle 
} 

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) { 

} 

@IBAction func cadenceStepper(_ sender: UIStepper) { 
    targetCadenceLabel?.text = Int(sender.value).description 
} 

@IBAction func goPremiumTapped(_ sender: UIButton) { 
    print("Go Premium Button Tapped") 
}  
}

來源

2016-09-28 Jerett Gordon

設置一個異常斷點，發現哪一行導致崩潰的 – Paulw11

請參閱http://www.raywenderlich.com/10209/my-app-crashed-now-what-part-1學習如何調試碰撞。結合重複問題，你可以找出你的問題。 – rmaddy

檢查零條件第一就是這樣，然後分配給tabbaritem圖像..... 如果讓incomingSelectedImage =的UIImage（命名爲：「settings_icon」）？withRenderingMode（.alwaysOriginal）{？ tabBarItem .selectedImage = incomingSelectedImage } –

您正在展開中只有一個在你的viewDidLoad線和多數民衆贊成在這裏：

let incomingSelectedImage: UIImage! = UIImage(named: "settings_icon")?.withRenderingMode(.alwaysOriginal)

與異常斷點，這是代碼崩潰行確認後，你可能想要做

let incomingSelectedImage:UIImage? ..........................

來源

2016-09-28 02:26:44

Swift 3 viewDidLoad（） - 致命錯誤：意外地發現零，同時展開一個可選值

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