输入“myViewController”不符合Swift中的协议UIPIckerDataSource [英] Type "myViewController" does not conform to protocol UIPIckerDataSource in Swift

问题描述

我只是在Swift中创建一个新类，它叫做 myViewController ，它是一个 UIViewController 。
现在我正在尝试将其设为UIPickerViewDelegate和DataSource，但我收到了一个奇怪的错误

I just create a new class in Swift, it's called myViewController and it's a UIViewController. Now I'm trying to make it a UIPickerViewDelegate and DataSource but i got a strange error

import UIKit

class myViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
   ...
}

它说类型myViewController不符合UIPickerViewDataSource上的协议UIPIckerDataSource 。

这是Xcode-Beta 3的错误吗？

推荐答案

您需要实现 UIPickerViewDataSource 和 UIPickerViewDelegate ，如果你想要符合这些协议。

You need to implement all the required methods of UIPickerViewDataSource and UIPickerViewDelegate, if you want to conform to these protocols.

Swift在协议方面更像java，因为如果你没有实现协议声明的所有必需方法，你将得到编译时错误而不是运行时异常。

Swift is more like java when it comes to protocols because if you don't implement all the required methods declared by a protocol you are going to get a compile time error instead of a run time exception.

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