ios - 实例成员不能用于类型 - 错误

Question

我遇到了一个奇怪的错误，但没有成功地修复它。我有一些链接文件，我在一个文件 (ViewController) 中调用一个函数，该函数在另一个文件 (Sign.swift) 中定义。 Sign.swift 中的函数创建在另一个文件 (GameState.swift) 中定义的输出。我不确定这有什么问题，我做了很多研究，甚至 this answer没有帮助。 (代码下的错误)。

ViewController.swift:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

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

    @IBOutlet weak var computerLabel: UILabel!
    @IBOutlet weak var output: UILabel!
    @IBOutlet weak var rockButton: UIButton!
    @IBOutlet weak var paperButton: UIButton!
    @IBOutlet weak var scissorsButton: UIButton!
    @IBOutlet weak var playAgain: UIButton!

    @IBAction func rockButtonPressed(_ sender: UIButton) {
        computerLabel.text = randomSign()
        var playerChoice = Sign.rock
        var output = Sign.checkInputs(playerChoice, computerLabel.text) //Error 1 is here
    }

    @IBAction func paperButtonPressed(_ sender: UIButton) {

    }

    @IBAction func scissorsButtonPressed(_ sender: UIButton) {

    }

    @IBAction func playAgainPressed(_ sender: UIButton) {

    }


}

Sign.swift:

import Foundation
import GameplayKit

let randomChoice = GKRandomDistribution(lowestValue: 0, highestValue: 2)

func randomSign() -> String {
    let sign = randomChoice.nextInt()
    if sign == 0 {
        return "👊"
    }
    else if sign == 1 {
        return "🖐"
    }
    else {
        return "✌️"
    }
}

enum Sign {
    case rock, paper, scissors

    var emoji: String {

        switch self {

        case .rock:
            return "👊"
        case.paper:
            return "🖐"
        case.scissors:
            return "✌️"
        }
    }

    func checkInputs(_ user: Sign, opponent: Sign) -> String {
        var outcome = GameState.draw
        if (opponent == .rock) {
            if (emoji == "👊") {
                outcome = .draw
            }
            else if (emoji == "🖐") {
                outcome = .win
            }
            else {
                outcome = .lose
            }
        }
        else if (opponent == .paper) {
            if (emoji == "👊") {
                outcome = .lose
            }
            else if (emoji == "🖐") {
                outcome = .draw
            }
            else {
                outcome = .win
            }
        }
        else if (opponent == .scissors) {
            if (emoji == "👊") {
                outcome = .win
            }
            else if (emoji == "🖐") {
                outcome = .lose
            }
            else {
                outcome = .draw
            }
        }

        return outcome //Error 2 is here
    }

}

GameState.swift:

import Foundation

enum GameState {
    case start, win, lose, draw

    var text: String {

        switch self {
        case.start:
            return "Game started!"

        case.win:
            return "You win!"

        case.lose:
            return "You lose!"

        case.draw:
            return"It's a draw!"
        }

    }

}

我在两个文件中都收到错误:错误 1(ViewController.swift 中的注释行)有以下错误消息:

Instance member 'checkInputs` cannot be used on type 'Sign'; did you mean to use a value of this type instead?

不幸的是，我不明白我要从上面的消息中修复什么，我是 Swift 的新手。

错误 2(Sign.swift 中的注释行)包含此消息:

Cannot convert return expression of type 'GameState' to return type 'String'

同样，我不明白这里发生了什么。我的 GameState.swift 文件中没有任何错误，所以这意味着所有错误都应该在 ViewController.swift 和 Sign.swift 中>。我应该如何修复这些错误？

编辑:我更新了我的代码，现在看起来像这样:

ViewController.swift:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

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

    func computerChoose() {

    }

    @IBOutlet weak var computerLabel: UILabel!
    @IBOutlet weak var output: UILabel!
    @IBOutlet weak var rockButton: UIButton!
    @IBOutlet weak var paperButton: UIButton!
    @IBOutlet weak var scissorsButton: UIButton!
    @IBOutlet weak var playAgain: UIButton!

    @IBAction func rockButtonPressed(_ sender: UIButton) {
        var random = randomSign()
        var stringRandom = ""
        switch random {
        case .rock :
            stringRandom = "👊"
        case .paper:
            stringRandom = "🖐"
        case .scissors:
            stringRandom = "✌️"
        }
        var playerChoice = Sign.rock
        var output = Sign.checkInputs(random)
        computerLabel.text = stringRandom
    }

    @IBAction func paperButtonPressed(_ sender: UIButton) {

    }

    @IBAction func scissorsButtonPressed(_ sender: UIButton) {

    }

    @IBAction func playAgainPressed(_ sender: UIButton) {

    }


}

Sign.swift:

import Foundation
import GameplayKit

let randomChoice = GKRandomDistribution(lowestValue: 0, highestValue: 2)

func randomSign() -> Sign {
    let sign = randomChoice.nextInt()
    if sign == 0 {
        return .rock
    }
    else if sign == 1 {
        return .paper
    }
    else {
        return .scissors
    }
}

enum Sign {
    case rock, paper, scissors

    var emoji: String {

        switch self {

        case .rock:
            return "👊"
        case.paper:
            return "🖐"
        case.scissors:
            return "✌️"
        }
    }

    static func checkInputs(_ opponent: Sign) -> GameState {
        var outcome = GameState.draw
        if (opponent == .rock) {
            if (emoji == "👊") { //Error Emoji
                outcome = .draw
            }
            else if (emoji == "🖐") { //Error Emoji
                outcome = .win
            }
            else {
                outcome = .lose
            }
        }
        else if (opponent == .paper) { //Error Emoji
            if (emoji == "👊") {
                outcome = .lose
            }
            else if (emoji == "🖐") { //Error Emoji
                outcome = .draw
            }
            else {
                outcome = .win
            }
        }
        else if (opponent == .scissors) {
            if (emoji == "👊") { //Error Emoji
                outcome = .win
            }
            else if (emoji == "🖐") { //Error Emoji
                outcome = .lose
            }
            else {
                outcome = .draw
            }
        }

        return outcome
    }

}

注意:新错误出现在带有注释 Error Emoji 的每一行，错误消息如下:

Instance member 'emoji' cannot be used on type 'Sign'

GameState.swift:未更改。

在此方面，我将不胜感激。

Answer 1

如果您需要在没有实例的情况下使用该方法，您需要将该方法声明为static。

static func checkInputs(_ user: Sign, opponent: Sign) -> String

注意:您似乎没有使用您传递的 user。在我看来，您可以跳过询问该参数并将其用作 playerChoice 的实例方法。

func checkInputs(opponent: Sign) -> String {
    // Your logic
}

然后像这样使用它

playerChoice.checkInputs(opponent: randomSign())

第二个错误是因为您试图返回 Sign 的实例而不是 String。您需要将返回类型更改为 Sign 或将 outcome 中的 Sign 转换为 String - outcome.text 就像@Larme 指出的那样？