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@IBOutlet weak var enterName: UITextField!
@IBOutlet weak var presentName: UITextView!
@IBOutlet weak var independceStatue: UITextField!
@IBOutlet weak var driverSelection: UITextField!
var entity : [Entity] = []
var nameList : [String] = []
var period1 = ""
var counting = 0
override func viewDidLoad() {
super.viewDidLoad()
let context = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
let request = NSFetchRequest(entityName: "Entity")
var results : [AnyObject]?
do{
results = try context.executeFetchRequest(request)
} catch {
results = nil
}
if results != nil {
self.entity = results as! [Entity]
}
if !entity.isEmpty{
presentName.text = entity.last?.period1Core
}
}
func setValues() {
nameList = [enterName.text!]
}
@IBAction func setName(sender: UIButton) {
setValues()
for item in nameList{
period1 += (item + " ")
}
presentName.text = period1
enterName.text = ""
}
@IBAction func start(sender: UIButton) {
let context = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
let entity = NSEntityDescription.insertNewObjectForEntityForName("Entity", inManagedObjectContext: context) as! Entity
entity.period1Core = presentName.text
do {
try context.save()
print("Item Saved")
} catch _ {
print("Saved Failed")
}
**Problem ->** let randomIndex = Int(arc4random_uniform(UInt32(nameList.count)))
driverSelection.text! = nameList[randomIndex]
print(randomIndex)
}
我试图随机出从数组名nameList
挑一个元素,但是当我运行程序和打印randomIndex
,第一次后,我按下按钮,将始终返回数组中的最后一个元素。无法随机挑选一个元素的数组雨燕
如果我退出模拟器并再次运行它,当我按下按钮时,它会返回我fatal error Array Index is out of range
。我的代码有什么问题,为什么我不能从数组中随机选择一个元素?
在哪一行,您在接收到所述运行时错误的参数值可能会出现在开始崩溃'致命错误数组索引超出范围',因为'arc4random_uniform'函数总是返回一个介于0和传递的参数之间的随机数字,在行driverSelection.text中减去1. –
! = nameList [randomIndex] – 123558
对不起,我不小心指向错误的行在driverSelection.text接收到错误! = nameList [randomIndex] – 123558