UITextField转换为UILabel [英] UITextField to Int to UILabel

问题描述

我已经习惯了C#和Java，Swift绝对是另一种野兽！

I'm used to C# and java, swift is definitely a different beast!

我一直在努力几个小时才能使它正常工作.这也是很简单的事情！我只想从UITextField中获取文本并将其转换为Int，然后将Int发送到UILabel！

I've been struggling for hours trying to get this to work. It is something so simple as well! I just want to get the text from a UITextField and turn it into an Int and then send the Int to a UILabel!!

互联网上的许多答案根本没有用！

So many answers on the internet haven't worked at all!

这是我现在遇到的错误. (使用Xcode 8.2.1和Swift 3.0.2 )

This is the error i'm getting now. (using Xcode 8.2.1 and Swift 3.0.2)

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var firstTextField: UITextField!
    @IBOutlet weak var secondTextField: UITextField!
    @IBOutlet weak var sumLabel: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func calculateButton(_ sender: UIButton) {
        let firstNumber = Int(firstTextField.text!)
        let secondNumber = Int(secondTextField.text!)

        //ERROR: 'init' has been renamed to 'init'(describing:)'
        sumLabel.text = String(firstNumber + secondNumber)
    }

}

谢谢大家！

推荐答案

首先获取Int:

let firstNumber = Int(firstTextField.text!) ?? 0

当无法将文本解析为Int时，?? 0提供默认值.

The ?? 0 provides a default value when the text cannot be parsed to an Int.

转换回String很简单:

sumLabel.text = String(firstNumber)

但是，如果要获取分组分隔符，则可能要使用NumberFormatter.

However, you might want to use NumberFormatter instead if you want to get grouping separators.

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