【发布时间】：2019-02-15 18:36:15
【问题描述】：
我遇到了一个奇怪的错误，并且尝试修复它没有运气。我有一些链接文件，我正在一个文件 (ViewController) 中调用另一个文件 (Sign.swift) 中定义的函数。 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 也没有帮助。 （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!"
}
}
}
我在两个文件中都遇到错误：错误 1（ViewController.swift 中的注释行）具有以下错误消息：
实例成员“checkInputs”不能用于“Sign”类型；你是否 意思是改用这种类型的值？
很遗憾，我不明白上述消息的含义是什么，我是 Swift 新手。
错误 2（Sign.swift 中的注释行）有此消息：
无法将“GameState”类型的返回表达式转换为返回类型 '字符串'
再说一次，我不明白这里发生了什么。我的GameState.swift 文件中没有任何错误，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：我已经更新了我的代码，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：新错误出现在每行注释Error Emoji，并带有以下错误消息：
实例成员 'emoji' 不能用于类型 'Sign'
GameState.swift：不变。
我将不胜感激。
【问题讨论】：
-
checkInputs是实例函数，而不是static函数。您需要使用Sign类型的值调用它或将其设为static。后者看起来像。 -
你需要知道，在OOP中，有Instance/Object方法和Class方法。如何定义它们取决于语言（在 Swift 中是静态的还是非静态的），但与在 Swift 中一样，您正在调用
checkInputs()方法，因为它是一个类而不是一个实例，但它被定义为一个实例方法。对于另一个问题，您的意思是return outcome.text吗？