Swift: display a random array index every button click - swift

Question

I have a swift class that reads lines from a text document and prints out the first line. After, every time a button is clicked a new line is read out.
What I want is to have a random line printed out the first time, and then a random line printed out after every button click.
Here's what I have so far:
import Foundation
import UIKit
class InfoController: UIViewController {
// MARK: Properties
#IBOutlet weak var difficultylevel: UILabel!
var i:Int = 0
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func readFile(){
if let path = NSBundle.mainBundle().pathForResource("easymath", ofType: "txt"){
var data = String(contentsOfFile:path, encoding: NSUTF8StringEncoding, error: nil)
if let content = data {
let myStrings = content.componentsSeparatedByCharactersInSet(NSCharacterSet.newlineCharacterSet())
let randomIndex = Int(arc4random_uniform(UInt32(myStrings.count)))
difficultylevel.text = myStrings[randomIndex]
}
}
}
#IBAction func difficultybutton(sender: UIButton) {
difficultylevel.text = // TODO insert random index of "myStrings" array here
}
}
However, I cannot access the myStrings array at the TODO portion inside the button click. Any help on how to set this up?

Answer 1

Variable scope in Swift is limited to the brackets of the function. So to make myStrings available outside of your readFile() function, you need to declare it as a property for the class:
#IBOutlet var difficultyLevel: UILabel? // BTW your IBOutlet should not be weak
var i: Int = 0
var myStrings: [String]?
Since you are going to use the random functionality over and over, we can abstract the function like this
func randomString() -> String? {
if let strings = myStrings {
let randomIndex = Int(arc4random_uniform(UInt32(myStrings.count)))
return strings[randomIndex]
}
return nil
}
then your instantiation will be like this
if let content = data {
myStrings = content.componentsSeparatedByCharactersInSet(NSCharacterSet.newlineCharacterSet())
difficultyLevel.text = randomString()
}
Then, your difficultybutton function will be (with an abstracted random string function)
// Changed the name for better readibility
#IBAction func difficultyButtonTapped(sender: UIButton) {
difficultyLevel.text = randomString()
}
Finally, there isn't any code that calls the readFile function, so you should add it to probably the viewDidLoad function as #CharlesCaldwell points out
override func viewDidLoad() {
super.viewDidLoad()
readFile()
}