如何根据变量更改 SWIFT 中的图像，单击使用 IF 语句的按钮

Question

这是一个简单的程序，它创建一个随机数并将其与用户在文本字段中输入的数字进行比较。这基本上是一个“猜猜我举起多少根手指？”程序。

我想要做的是在用户猜测正确时根据“var randomNumber”在 UIImageView 中显示图像，并在用户猜测错误或输入大于 5 的数字时显示图像（交叉）。图像在开头显示一个问号。从 0 到 5 的图像是相应地显示 5 根手指的图像。

我必须像这样指定图像吗？我需要写下文件的扩展名吗？

hand.image = UIImage(named: "0")
hand.image = UIImage(named: "1")
hand.image = UIImage(named: "2")
hand.image = UIImage(named: "3")
hand.image = UIImage(named: "4")
hand.image = UIImage(named: "5")
hand.image = UIImage(named: "wrong")
hand.image = UIImage(named: "?")

还是这样？

let image0 = UIImage(named: "0")
let image1 = UIImage(named: "1")
let image2 = UIImage(named: "2")
let image0 = UIImage(named: "3")
let image1 = UIImage(named: "4")
let image2 = UIImage(named: "5")
let image0 = UIImage(named: "wrong")
let image1 = UIImage(named: "?")

我是否需要指定它们？

到目前为止没有任何效果，如果有人可以提供帮助，那就太好了。每次我按下“猜测按钮”时，应用程序都会崩溃。这是一项相当容易的任务，但由于我刚刚开始，我想知道它是如何完成的。提前致谢。

这是我目前的代码。

//
//  ViewController.swift
//  Finger Raten
//
//  Created by Daniel Bleyer on 04.07.15.
//  Copyright (c) 2015 DiBi. All rights reserved.
//

import UIKit

class ViewController: UIViewController{

@IBOutlet var hand: UIImageView!                   //image view

@IBOutlet weak var output: UILabel!                 //result (right/wrong)

@IBOutlet weak var input: UITextField!              //guessed number

@IBAction func guess(sender: AnyObject)        //guess button (comparing both numbers)

{


    var randomNumber = arc4random_uniform(6)  //random number

    var inputInt = input.text.toInt()                            //guessed number

    hand.image = UIImage(named: "0")          //does this code go here? or somewhere else?
    hand.image = UIImage(named: "1")          //does this code go here? or somewhere else?
    hand.image = UIImage(named: "2")          //does this code go here? or somewhere else?
    hand.image = UIImage(named: "3")          //does this code go here? or somewhere else?
    hand.image = UIImage(named: "4")          //does this code go here? or somewhere else?
    hand.image = UIImage(named: "5")          //does this code go here? or somewhere else?
    hand.image = UIImage(named: "wrong")  //does this code go here? or somewhere else?
    hand.image = UIImage(named: "?")          //does this code go here? is it RIGHT? This image
                                                                      //shows at the beginning, it is a question mark.


    if inputInt != nil && inputInt < 6                                                     //conditions (not empty/0-5)

    {

        if inputInt == Int(randomNumber)                                             //comparing random/guessed

        {

        output.text = "Right !";                                                              //right guess
        hand.image = UIImage(named: "\(randomNumber)")              //image showing 0-5 fingers
                                                                                                         //is this the right place?
            input.resignFirstResponder();                                              //hides numpad

        } else  {

                output.text = "Wrong, it was a \(randomNumber)";          //wrong guess, it was a ??
                hand.image = UIImage(named: "wrong)")                       //image of a cross (X)
                                                                                                         //is this the right place?
                    input.resignFirstResponder();                                      //hides numpad
                }


    } else  {

            output.text = "Enter a number from 0-5";                             //field empty or out of range
            hand.image = UIImage(named: "wrong")                            //image of a cross (X)
                                                                                                         //is this the right place?
                input.resignFirstResponder();                                          //hides numpad
            }
}

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.
    }
}

Answer 1

我在您的代码中做了一些清理工作。这未经测试，但我想提供一些关于您没有完全正确做的事情的反馈：何时使用var/let，什么是正确的文件名，不要使用; 等。请阅读评论。当您提供崩溃日志时，我将修改此代码 - 然后我将对其进行测试。

let maxInputInt: Int = 5 // this way you later don't search through the code to change value

override func viewDidLoad() {
    super.viewDidLoad()

    self.reset()
}

func reset() {
    output.text = NSLocalizedString("Enter a number from 0-5", ""); // always provide strings as NSLocalizedString - app is ready to translate in future versions. Without it you'd have to search through all source files
    // BTW you should name variables such way so it's obvious what is it, eg inputTextField, output/input is rather wrong
    hand.image = UIImage(named: "?")
}

func guess(sender: AnyObject) {
    var randomNumber = arc4random_uniform(maxInputInt + 1)

    let inputInt = input.text.toInt() // this won't change, should be declared as let not int
    let wrongImage = UIImage(named: "wrong")

    if inputInt <= maxInputInt { // int is not an object, it cannot be nil, nil is for objects only
        if inputInt == Int(randomNumber) {
            output.text = NSLocalizedString("Right !", "");
            hand.image = UIImage(named: "\(randomNumber)")
        } else {
            output.text = NSLocalizedString("Wrong, it was a \(randomNumber)", "")
            hand.image = wrongImage
        }
    } else {
        hand.image = wrongImage
    }
    input.resignFirstResponder() // you do it under all conditions, so don't repeat yourself (DRY)
}