Random Swift3中的随机选择和UILabel

我正在为这个应用程序选择的膳食编写一些代码

我的想法是：我调用arc4random_统一方法，它将返回5个数字，我只需要设置每个数字表示哪些食物，并通过chosenmeat.text显示。谁能告诉我怎么了？ 如果你有不知道我做了什么的代码

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

@IBOutlet weak var meals: UILabel!// not really important

@IBOutlet weak var chosenMeal: UILabel!//This  label is used to the page to show detail about what meal that app recommended,
 while I push  func(checkMeals) that the compiler get me an error : "fatal error: unexpectedly found nil while unwrapping an Optional value"



@IBOutlet weak var pickerView: UIPickerView! // used to chose breakfast or lunch


@IBAction func checkMeals(_ sender: UIButton) {

  breakFast = [ "sandwich","Hamburgers", "beef" ,"vegetable", "egg"]

    if meals.text == "breakfast" {


        let breakFast = arc4random_uniform(5) // 

        switch breakFast {
        case 0:
            chosenMeal.text = "sandwich"
        case 1:
             chosenMeal.text = "Hamburgers"
        case 2:
             self.chosenMeal.text = "beef"
        case 3:
             chosenMeal.text = "vegetable"

        case 4:
             chosenMeal.text = "egg"

        default:
            break

        }

    }   else if meals.text == "lunch" {
     let  lunch = (arc4random_uniform(5)+5)

        switch lunch {
        case 6:
            chosenMeal.text = "some1"
        case 7:
            chosenMeal.text = "some2"
        case 8:
            chosenMeal.text = "some3"
        case 9:
          chosenMeal.text = "some4"

        case 10:
            chosenMeal.text = "some5"

        default:
            break

        }



let foods = ["breakfast", "lunch"]

func numberOfComponents(in pickerView: UIPickerView) -> Int
{
    return 1
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
{
    return foods[row]
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
{
    return foods.count
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
{
    meals.text = foods[row]
}



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.
}

---

}

请确保已在情节提要中正确绑定Chosenmeid UILabel。好的，谢谢。