xcode 实例成员不能用于类型 - 错误

Instance member cannot be used on type - error

提问by Hyman Bashford

I have been having a strange error, and have had no luck in trying to fix it. I've got some linked files, and I'm calling a function in one file (ViewController) that's defined in another file (Sign.swift). The function in Sign.swiftcreates output defined in another file (GameState.swift). I'm not sure what's wrong with this, I've done a lot of research, and even this answerdidn't help. (errors under code).

我遇到了一个奇怪的错误，并且没有尝试修复它。我有一些链接文件，我正在调用另一个文件 ( ViewController) 中定义的文件 ( ) 中的函数Sign.swift。函数 inSign.swift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，即使这个答案也没有帮助。（代码下的错误）。

ViewController.swift:

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:

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:

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!"
        }

    }

}

I am getting errors in both files: Error 1 (commented line in ViewController.swift) has the below error message:

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

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

实例成员“checkInputs”不能用于“Sign”类型；您的意思是使用这种类型的值吗？

Unfortunately I don't understand what I'm mean to fix from the above message, I'm new to Swift.

不幸的是，我不明白我想从上面的消息中解决什么问题，我是 Swift 的新手。

Error 2 (commented line in Sign.swift) has this message:

错误 2（中的注释行Sign.swift）有以下消息：

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

无法将“GameState”类型的返回表达式转换为“String”类型

Again, I don't understand what's happening here. I don't have any errors in my GameState.swiftfile though, so that means all errors should be in ViewController.swiftand Sign.swift. How should I fix these errors?

同样，我不明白这里发生了什么。GameState.swift不过，我的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 中Sign.swift。我应该如何修复这些错误？

EDIT:I have updated my code, it now looks like this:

编辑：我已经更新了我的代码，现在看起来像这样：

ViewController.swift:

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:

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
    }

}

Note:New errors are on every line with the comment Error Emoji, with this error message:

注意：新的错误出现在每一行带有注释的地方Error Emoji，错误信息如下：

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

实例成员 'emoji' 不能用于类型 'Sign'

GameState.swift: Unchanged.

GameState.swift:不变。

I would appreciate all help with this.

我将不胜感激。

回答by Rakesha Shastri

If you need to use the method without an instance, you need to declare the method as static.

如果需要在没有实例的情况下使用该方法，则需要将该方法声明为static.

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

Note: You do not seem to using the userthat you pass. IMO you could skip asking for that parameter and use it as an instance method with playerChoice.

注意：您似乎没有使用user您通过的 。IMO 您可以跳过要求该参数并将其用作playerChoice.

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

And then use it like this

然后像这样使用它

playerChoice.checkInputs(opponent: randomSign())

The second error is because you are trying to return an instance of Signinstead of a String. You need to either change the return type to Signor covert the Signin outcometo String- outcome.textlike @Larme pointed out?

第二个错误是因为您试图返回一个实例Sign而不是一个String. 您需要或是改变返回类型Sign或隐蔽的Sign在outcome以String-outcome.text像@Larme指出？