Type "myViewController" does not conform to protocol UIPIckerDataSource in Swift

Question

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 {    ... } 

It says Type "myViewController" does not conform to protocol UIPIckerDataSource over the UIPickerViewDataSource.

Is it a bug of Xcode-Beta 3??

Answer 1

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

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.

Answer 2

Fix-it in XCode 8.1 inserts a deprecated version of the method below if you're using Swift 3:

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {     return componentNumber } 

In XCode 10.0+

func numberOfComponents(in pickerView: UIPickerView) -> Int {     return componentNumber }