ios 无法将“Int”类型的值转换为预期的参数类型“UInt32”
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Cannot convert value of type 'Int' to expected argument type 'UInt32'
提问by Tom Fox
Any ideas on what I can do to fix this error, I am trying to get ten random numbers so I can then query firebase for a set of questions which contain the random numbers. Screenshot down below. I have also added the code...
关于我可以做些什么来修复这个错误的任何想法，我正在尝试获取十个随机数，以便我可以在 firebase 中查询一组包含随机数的问题。下面截图。我还添加了代码...
import UIKit
import Firebase
class QuestionViewController: UIViewController {
var amountOfQuestions = 2
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(true)
//Use a for loop to get 10 questions
for _ in 1...10{
//generate a random number between 1 and the amount of questions you have
var randomNumber = Int(arc4random_uniform(amountOfQuestions - 1)) + 1
//The reference to your questions in firebase (this is an example from firebase itself)
let ref = Firebase(url: "https://dinosaur-facts.firebaseio.com/dinosaurs")
//Order the questions on their value and get the one that has the random value
ref.queryOrderedByChild("value").queryEqualToValue(randomNumber)
.observeEventType(.ChildAdded, withBlock: {
snapshot in
//Do something with the question
println(snapshot.key)
})
} }
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func truepressed(sender: AnyObject) {
}
@IBAction func falsePressed(sender: AnyObject) {
}
采纳答案by JAL
Make your amountOfQuestionsvariable an UInt32rather than an Intinferred by the compiler.
使您的amountOfQuestions变量成为UInt32而不是Int编译器推断的变量。
var amountOfQuestions: UInt32 = 2
// ...
var randomNumber = Int(arc4random_uniform(amountOfQuestions - 1)) + 1
arc4random_uniformrequires a UInt32.
arc4random_uniform需要一个UInt32.
From the Darwin docs:
从达尔文文档：
arc4random_uniform(u_int32_t upper_bound);
回答by yesthisisjoe
Declare amountOfQuestions as a UInt32:
将 amountOfQuestions 声明为 UInt32：
var amountOfQuestions: UInt32 = 2
PS: If you want to be grammatically correct it's numberof questions.
PS：如果你想在语法上正确，那就是问题的数量。
回答by gaskbr
First thing: The method "arc4random_uniform" expects an argument of type UInt32, so when you put that subtraction there, it converted the '1' you wrote to UInt32.
第一件事：方法“arc4random_uniform”需要一个 UInt32 类型的参数，所以当你把减法放在那里时，它会将你写的“1”转换为 UInt32。
Second thing: In swift you can't subtract a UInt32 (the '1' in your formula) from an Int (in this case 'amountOfQuestions').
第二件事：在 swift 中，您不能从 Int（在本例中为“amountOfQuestions”）中减去 UInt32（公式中的“1”）。
To solve it all, you'll have to consider changing the declaration of 'amountOfQuestions' to:
要解决这一切，您必须考虑将 'amountOfQuestions' 的声明更改为：
var amountOfQuestions = UInt32(2)
That should do the trick :)
这应该够了吧 ：）
