当尝试将UITextField文本转换为Int Xcode 7时，给出了一个错误

I'm new to programming and after doing some tutorials online I decided to make my own app with Xcode 7 to be able to run my app on my iPhone. But when I try to get input data from a text field and put it into a var it gives me an error. I have tried to use the following:

我是编程新手，在网上做了一些教程之后，我决定用Xcode 7制作自己的应用程序，以便能够在我的iPhone上运行我的应用程序。但是当我尝试从文本字段获取输入数据并将其放入var时，它会给我一个错误。我试过使用以下内容：

var initialChips = 0
var initialBlind = 0

@IBOutlet weak var txtBlind: UITextField!
@IBOutlet weak var txtChips: UITextField!
@IBOutlet weak var doneBtn: UIBarButtonItem!

@IBAction func doneBtn(sender: AnyObject) {

    let initialChips:Int? = Int(txtChips.text)
    let initialBlind:Int? = Int(txtBlind.text)
}

Xcode will ask to put a "!" after ".text" but after doing that it gives me a warning: "Initialization of immutable value 'initialChips' (or 'initialBlind' was never used: consider replacing with assignment to '_'or removing it".

Xcode会要求放一个“！”在“.text”之后，但在这之后它给了我一个警告：“初始化不可变值'initialChips'（或'initialBlind'从未使用过：考虑用赋值替换为'_'或删除它”。

What can I do to set a value to my var?

我该怎么做才能为我的var设置一个值？

2 个解决方案

#1

The thing is that the let initialChips:Int? = Int(txtChips.text) generates a new variable called initialChips (different from the variable from the class). The difference between let and var is that let is inmutable and var is not. You should do:

那件事就是让initialChips：Int？ = Int（txtChips.text）生成一个名为initialChips的新变量（与该类中的变量不同）。 let和var之间的区别在于let是不可变的而var不是。你应该做：

initialChips = Int(txtChips.text)

To assign the integer from the UITextField to your class variable rather than declaring a new inmutable variable (with the same name) and do nothing with it.

将UITextField中的整数分配给类变量，而不是声明一个新的不可变变量（具有相同的名称），并且不对其执行任何操作。

Of course, the same happens with initialBlind

当然，initialBlind也是如此

EDIT:

编辑：

Try the following:

请尝试以下方法：

@IBAction func doneBtn(sender: AnyObject) {

    if let initialChips = Int(txtChips.text!) {
        self.initialChips = initialChips
    }else {
        self.initialChips = 0
    }

    if let initialBind = Int(txtBind.text!) {
        self.initialBind = initialBind
    }else {
        self.initialBind = 0
    }
}

#2

You should add the ! after the closing parenthesis, not after .text, like so:

你应该添加！在右括号之后，而不是在.text之后，如下：

let initialChips:Int? = Int(txtChips.text)!

#1

initialChips = Int(txtChips.text)