Question

我想知道检查/验证我的影响文本字段的最简单最简单的方法是什么，它只能从1-80输入？我的编码仍然非常生疏，我尝试做了＆＃34; if（Int（impact.text！）！= 1 ... 80）＆＃34;但它没有用。

的ViewController

import UIKit
import FirebaseDatabase

class TryingOut2Controller: UIViewController {

    @IBOutlet var titleLabel: UILabel!
    @IBOutlet var impact: UITextField!
    @IBOutlet var rigour: UITextField!
    @IBOutlet var response: UITextField!
    @IBOutlet var total: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        titleLabel.text = postData[myIndex]

        impact.addTarget(self, action: #selector(textChanged), for: .editingChanged)
        rigour.addTarget(self, action: #selector(textChanged), for: .editingChanged)
        response.addTarget(self, action: #selector(textChanged), for: .editingChanged)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @objc func textChanged() {
        let impactValue = Int(impact.text!)
        let rigourValue = Int(rigour.text!)
        let responseValue = Int(response.text!)
        total.text = String(describing:
            (impactValue ?? 0) + (rigourValue ?? 0) + (responseValue ?? 0)
        )
    }

    @IBAction func button1(_ sender: Any) {

        if (Int(impact.text!) != 1...80)
        {
            //create alert
        }
        else {

        }

Answer 1

最好的方法是实现委托函数textField(_:shouldChangeCharactersIn:replacementString:)（参见https://developer.apple.com/documentation/uikit/uitextfielddelegate/1619599-textfield）

您可以实现此操作以检查当前值加上新输入是否可以转换为Int，并且包含1 ... 80。

Answer 2

最好的方法是添加一个动作方法＆＃34;编辑已更改＆＃34;到你的textField：并检查您的文本字段是否具有大于80的值

   @IBAction func valueChange(_ sender: Any) {
          if let number = Int(self.impact.text!){
               if number > 80 || number < 0 {
                    let alert = UIAlertController(title: "Error", message: "Enter a Valid Number", preferredStyle: .alert)
                    let alertAction = UIAlertAction(title: "OK", style: .default, handler: nil)
                    alert.addAction(alertAction)
                    self.present(alert, animated: true, completion: nil)
               }
          }
     }

Answer 3

字符串甚至可以直接与字母表中的字母或数字进行比较。您可以将范围比较为：例如

    let value = "90"
    if value > "1" && value < "80" {
        print("in range 1-80")
    } else {
        print("out of range 1-80")
        //create alert in your case
    }
    //prints  out of range 1-80

希望有所帮助...... !!!

Answer 4

func textField(textField: UITextField,
    shouldChangeCharactersInRange range: NSRange,
    replacementString string: String) -> Bool
{
    var startString = ""
    if (self.impact.text! = nil)
    {
        startString += self.impact.text!
    }
    startString += string
    var limitNumber = startString.toInt()
    if limitNumber > 80 || limitNumber < 0
    {
        return false
    }
    else
    {
        return true;
    }
}

检查/验证文本字段只能是1-80

4 个答案: