ios - 不符合协议(protocol) UIPickerViewDataSource

Question

我不知道我的代码有什么问题。我尝试按照教程进行操作，但发生了同样的错误。

错误:

Type 'FourthViewController' does not conform to protocol 'UIPickerViewDataSource'

这是我的代码:

import UIKit

let characters = ["Jaja Bink", "Luke", "Han Solo", "Princess Leia"];

let weapons = ["LightSaber", "Pistol", "Keris"];

class FourthViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

    @IBOutlet weak var doublePicker: UIPickerView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 2
    }


    func pickerView(pickerView: UIPickerView,
                    titleForRow row: Int,
                                forComponent component: Int) -> String? {

        if component == 0 {
            return characters[row]
        } else {
            return weapons[row]
        }

    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int? {
        if component == 0 {
            return characters.count
        } else {
            return weapons.count
        }
    }

}

Answer 1

替换 UIPickerViewDataSource 协议(protocol)方法的弃用版本，如果您使用的是 Swift 3 可能适合您。

已弃用的协议(protocol)方法

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 1
}

Swift 3 协议(protocol)的最新方法

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

注意:对于其他必需的协议(protocol)方法也是如此。即

Deprecated:

func pickerView(pickerView: UIPickerView!, numberOfRowsInComponent component: Int) -> Int

Recent Version:

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int