core-data - UIPickerView 与 Core Data Swift4

Question

我正在尝试重用 swift 7.3 中的代码。我觉得我很亲近。当我在模拟器上尝试代码时，选择器视图是空的，但是当我尝试使用它时，我只显示一个数据。

我也尝试适应和其他代码将数据从核心数据加载到它，没有工作。

任何想法？

谢谢

    import CoreData
    class ViewController: UIViewController, UIPickerViewDelegate, UIImagePickerControllerDelegate {
        @IBOutlet weak var TextField: UITextField!
        @IBOutlet weak var stylePicker: UIPickerView!
        var styleData = [PilotBase]()
        override func viewDidLoad() {
            super.viewDidLoad()
            let appDelegate = UIApplication.shared.delegate as! AppDelegate
            let context = appDelegate.persistentContainer.viewContext
            let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "PilotBase")
            do {
                styleData = try context.fetch(fetchRequest) as! [PilotBase]
            } catch let err as NSError {
               print(err.debugDescription)
            } 
            let request = NSFetchRequest<NSFetchRequestResult>(entityName: "PilotBase")
            request.returnsObjectsAsFaults = false   
            do{
                let result = try context.fetch(request)
                for data in result as! [NSManagedObject]{
                    print(data.value(forKey: "name") as! String)
                }
            }catch{
                print("Failed")
            }     
        }
        func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
            return 1
        } 
        func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
            if component == 0 {
                return styleData.count
            } else {
                return 0
            }    
        } 
        func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {  
            if component == 0 {
                return styleData[row].name
            } else {
                return nil
            }
        } 
        func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {     
            print(styleData[row])
            stylePicker.selectRow(row, inComponent: 0, animated: true)
                    TextField.text = styleData[row].name  
        }
}

将数据添加到 Core Data 的代码下方。

    @IBAction func Save(_ sender: Any) {
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let entity = NSEntityDescription.entity(forEntityName: "PilotBase", in: context)
    let newUser = NSManagedObject(entity: entity!, insertInto: context)

    newUser.setValue(TextField.text!, forKey: "name")


    do{
        try context.save()
    }catch{
        print("failed saving")
    }
}

标签： core-dataswift3uipickerview