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Jack Bashford
Jack Bashford

Reputation: 44087

Instance member cannot be used on type - error

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.swift creates 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 answer didn't help. (errors under code).

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!"
        }

    }

}

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

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

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

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

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

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

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

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
    }

}

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

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

GameState.swift: Unchanged.

I would appreciate all help with this.

Upvotes: 2

Views: 24869

Answers (1)

Rakesha Shastri
Rakesha Shastri

Reputation: 11243

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

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

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

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

And then use it like this

playerChoice.checkInputs(opponent: randomSign())

The second error is because you are trying to return an instance of Sign instead of a String. You need to either change the return type to Sign or covert the Sign in outcome to String - outcome.text like @Larme pointed out?

Upvotes: 13

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