Swift不符合協議

Question

將使用Swift 6構建的應用程序拉到現在使用6 beta的系統后，我得到了“ EventFormViewController不符合協議UIPickerViewDataSource”的信息。 我已經為此苦苦掙扎了幾天，有什么建議嗎？

import UIKit

var eventChoices = [
    ["5","10","15","30","45","60","90","120","150","180"],
    ["Hospital Committee","Peer Review","EHR Improvement","Quality Improvement","Business Development"], ]

class EventFormViewController: UIViewController,UIPickerViewDataSource,UIPickerViewDelegate{


    @IBOutlet weak var eventPicker: UIPickerView!
    @IBOutlet weak var eventLabel: UILabel!
    @IBOutlet weak var commentField: UITextField!


    func updateLabel(){
        let selectedTime = eventChoices[0][eventPicker.selectedRowInComponent(0)]
        let event = eventChoices[1][eventPicker.selectedRowInComponent(1)]


        eventLabel.text = "Chose \(event) for \(selectedTime) mins"
    }

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

    override func viewDidLoad() {
        super.viewDidLoad()

        }


        // Do any additional setup after loading the view.




    }

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

    // returns the number of 'columns' to display. func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return eventChoices.count }

    // returns the # of rows in each component..
    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{

        return eventChoices[component].count



    }



    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
        return eventChoices[component][row]    }

    func pickerView(pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
        if (component == 0) {
            return 50.0;
        }
        return 300.0;
    }



    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

Answer 1

您的代碼中存在很多問題。

1

函數頭被注釋。

// returns the number of 'columns' to display. func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return eventChoices.count }

應該是這樣的：

// returns the number of 'columns' to display.
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
{
    return eventChoices.count
}

2

您viewDidLoad在viewDidLoad實現之后關閉類定義。

應該是這樣的：

import UIKit

var eventChoices = [
    ["5","10","15","30","45","60","90","120","150","180"],
    ["Hospital Committee","Peer Review","EHR Improvement","Quality Improvement","Business Development"], ]

class EventFormViewController: UIViewController,UIPickerViewDataSource,UIPickerViewDelegate
{


    @IBOutlet weak var eventPicker: UIPickerView!
    @IBOutlet weak var eventLabel: UILabel!
    @IBOutlet weak var commentField: UITextField!


    func updateLabel()
    {
        let selectedTime = eventChoices[0][eventPicker.selectedRowInComponent(0)]
        let event = eventChoices[1][eventPicker.selectedRowInComponent(1)]


        eventLabel.text = "Chose \(event) for \(selectedTime) mins"
    }

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

    override func viewDidLoad()
    {
        super.viewDidLoad()
    }

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

    // returns the number of 'columns' to display.
    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
    {
        return eventChoices.count
    }

    // returns the # of rows in each component..
    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
    {
        return eventChoices[component].count
    }

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String!
    {
        return eventChoices[component][row]
    }

    func pickerView(pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat
    {
        var width  = 300.0 
        if (component == 0)
        {
            width = 50.0;
        }
        return width;
    }



    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */
}

Answer 2

您遇到一些輸入錯誤：

在didReceiveMemoryWarning之前，您需要使用一個方括號將類關閉。 因此，您的其他方法不在UIPickerViewDelegate的類中，因此委托認為，這些方法不存在。

因此，將方括號移到代碼末尾以關閉該類。

其次，在didReceiveMemoryWarning方法之后，您會犯一個錯誤。 您已經注釋掉了方法標頭：

 // returns the number of 'columns' to display. func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return eventChoices.count }

因此，將其更改為如下所示：

 // returns the number of 'columns' to display. 
 func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return eventChoices.count 
 }

最后但並非最不重要的一點是，您需要重寫didReceiveMemoryWarning方法。 因此更改：

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

對此：

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