我已经找到了很多关于如何在objective-c中执行此操作的指南,但我希望看到更多以Swift为导向的方法。
我有一个UITextField,用户输入货币价格。文本字段调用十进制键盘。但是,在iPad上,出现的键盘有一系列非小数符号。
基本上,对于每一次按键,我都希望不能将非数字或超过一个小数的任何内容输入到字段中。如果输入小数,我想不可能输入第二个小数。如果删除小数,我想确保用户可以再次输入小数。
关于如何在swift中正确执行此操作的任何想法?
我也看到像这里发布的解决方案: Limit UITextField to one decimal point Swift 但我不知道在哪里放置功能或我应该如何调用它们。每当我尝试在参数中输入NSRange时,我都会收到错误消息,表示我没有正确创建范围。
答案 0 :(得分:12)
这是一个简单的例子:
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var textField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.textField.delegate = self
}
//Textfield delegates
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool { // return NO to not change text
switch string {
case "0","1","2","3","4","5","6","7","8","9":
return true
case ".":
let array = Array(textField.text)
var decimalCount = 0
for character in array {
if character == "." {
decimalCount++
}
}
if decimalCount == 1 {
return false
} else {
return true
}
default:
let array = Array(string)
if array.count == 0 {
return true
}
return false
}
}
}
答案 1 :(得分:7)
通过使用NSScanner测试新字符串是否为数字,需要考虑多个小数:
func textField(textField: UITextField,
shouldChangeCharactersInRange range: NSRange,
replacementString string: String) -> Bool {
// Get the attempted new string by replacing the new characters in the
// appropriate range
let newString = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)
if newString.length > 0 {
// Find out whether the new string is numeric by using an NSScanner.
// The scanDecimal method is invoked with NULL as value to simply scan
// past a decimal integer representation.
let scanner: NSScanner = NSScanner(string:newString)
let isNumeric = scanner.scanDecimal(nil) && scanner.atEnd
return isNumeric
} else {
// To allow for an empty text field
return true
}
}
答案 2 :(得分:7)
Swift 2 版@Steve Rosenberg的解决方案
如果您不需要将输入限制为最多2个小数位(即“12.34”OK,“12.345”不正常),则在开头删除4行。
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var textField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.textField.delegate = self
}
//Textfield delegates
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool { // return false to not change text
// max 2 fractional digits allowed
let newText = (textField.text! as NSString).stringByReplacingCharactersInRange(range, withString: string)
let regex = try! NSRegularExpression(pattern: "\\..{3,}", options: [])
let matches = regex.matchesInString(newText, options:[], range:NSMakeRange(0, newText.characters.count))
guard matches.count == 0 else { return false }
switch string {
case "0","1","2","3","4","5","6","7","8","9":
return true
case ".":
let array = textField.text?.characters.map { String($0) }
var decimalCount = 0
for character in array! {
if character == "." {
decimalCount++
}
}
if decimalCount == 1 {
return false
} else {
return true
}
default:
let array = string.characters.map { String($0) }
if array.count == 0 {
return true
}
return false
}
}
}
答案 3 :(得分:5)
所有答案都使用'。'作为小数的有效分隔符,但在不同的本地化中,它可能是错误的。
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard !string.isEmpty else {
return true
}
let currentText = textField.text ?? ""
let replacementText = (currentText as NSString).replacingCharacters(in: range, with: string)
return replacementText.isDecimal()
}
extension String{
func isDecimal()->Bool{
let formatter = NumberFormatter()
formatter.allowsFloats = true
formatter.locale = Locale.current
return formatter.number(from: self) != nil
}
}
答案 4 :(得分:3)
这是受到了Wye的答案的启发,但它更紧凑,并且在我需要数字/十进制字段的地方工作。您可以通过修改正则表达式来适应只接受整数(取出spark-submit
并留下.?\\d{0,2}
)。同样,如果您不想限制小数点后的位数,则可以删除该限制(只需将其更改为^\\d*$
)
^\\d*\\.?\\d*
这允许构造数字字符串而不会拒绝输入,例如,以下是所有有效输入, func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let newString = (_timeQuantityField.text! as NSString).stringByReplacingCharactersInRange(range, withString: string)
let decimalRegex = try! NSRegularExpression(pattern: "^\\d*\\.?\\d{0,2}$", options: [])
let matches = decimalRegex.matchesInString(newString, options: [], range: NSMakeRange(0, newString.characters.count))
if matches.count == 1
{
return true
}
return false
}
给出有效结果):
(newString as NSString).floatValue
(即空字符串)产生0.0
收益率为0.0 .
收益率为1.0 1.
收益率为0.1 答案 5 :(得分:2)
以下是最简单的方法:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if (textField.text?.componentsSeparatedByString(".").count > 1 && string == ".")
{
return false
}
return string == "" || (string == "." || Float(string) != nil)
}
答案 6 :(得分:2)
经过测试并在 Swift 3和Swift 4 中工作,您也可以进行以下检查
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let existingTextHasDecimalSeparator = textField.text?.rangeOfString(".")
let replacementTextHasDecimalSeparator = string.rangeOfString(".")
if existingTextHasDecimalSeparator != nil && replacementTextHasDecimalSeparator != nil {
return false
}
else {
return true
}
}
答案 7 :(得分:2)
这是Swift 4解决方案:
import struct Foundation.CharacterSet
extension String {
var onlyNumbers: String {
let charset = CharacterSet.punctuationCharacters.union(CharacterSet.decimalDigits).inverted
return components(separatedBy: charset).joined()
}
}
答案 8 :(得分:2)
Swift 3 实现此UITextFieldDelegate方法以防止用户输入无效的数字:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let text = (textField.text ?? "") as NSString
let newText = text.replacingCharacters(in: range, with: string)
if let regex = try? NSRegularExpression(pattern: "^[0-9]*((\\.|,)[0-9]{0,2})?$", options: .caseInsensitive) {
return regex.numberOfMatches(in: newText, options: .reportProgress, range: NSRange(location: 0, length: (newText as NSString).length)) > 0
}
return false
}
它使用逗号或点作为小数分隔符,并允许2个小数位。
答案 9 :(得分:1)
这是我使用的。如果返回false,则调用者将使用textField.deleteBackward()
删除最后一个(违规)字符。
func isValidNumber(text: String) -> Bool {
let validChars: Set<Character> = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "."]
return (Set(text).isSubset(of: validChars) && ((text.components(separatedBy: ".").count - 1) <= 1))
}
或者您可以在函数中完成所有操作:
func isValidNumber2(textField: UITextField) -> Bool {
let validChars: Set<Character> = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "."]
let validNum = Set(textField.text!).isSubset(of: validChars) && ((textField.text!.components(separatedBy: ".").count - 1) <= 1)
if !validNum {
textField.deleteBackward()
}
return (validNum)
}
两者都简短,清晰,简单,高效。 (似乎第二个更干净......意见?)但是他们没有将输入限制在一个小数点......
答案 10 :(得分:1)
改善Naishta在 Swift 4 中的回应,这里有一个片段,允许您将文本字段长度限制为10个字符(额外奖励 - 不是帖子创建者要求的)和单个小数点:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let text = textField.text else { return true }
// Max 10 characters.
let newLength = text.count + string.count - range.length
if newLength > 10 { return false }
// Max one decimal point.
let existingTextHasDecimalSeparator = text.range(of: ".")
let replacementTextHasDecimalSeparator = string.range(of: ".")
if existingTextHasDecimalSeparator != nil && replacementTextHasDecimalSeparator != nil { return false }
return true
}
答案 11 :(得分:1)
以同样的方式做。下面的代码并没有防范多个.
,但也可以做你想要的。像你一样延伸它。
class Foo: NSObject, UITextFieldDelegate {
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
var result = true
if countElements(string) > 0 {
let numericInput = NSCharacterSet(charactersInString: "0123456789.-").invertedSet
if let badRange = string.rangeOfCharacterFromSet(numericInput) {
let substring = string.substringToIndex(badRange.startIndex)
let oldString: NSString = textField.text // necessary so we can use the NSRange object passed in.
textField.text = oldString.stringByReplacingCharactersInRange(range, withString: substring)
result = false
}
}
return result
}
}
答案 12 :(得分:0)
我们可以做得更好,而无需对允许的字符和分隔符进行硬编码。尤其是分隔符,因为它在不同的区域可能有所不同。我们还需要注意,用户可能会移动光标并粘贴文本。这是一个考虑到这一点的验证功能:
static func validateDecimalNumberText(for textField: UITextField, replacementStringRange: NSRange, string: String) -> Bool {
// Back key
if string.isEmpty {
return true
}
// Allowed charachters include decimal digits and the separator determined by number foramtter's (current) locale
let numberFormatter = NumberFormatter()
numberFormatter.maximumFractionDigits = 2
let allowedCharacters = CharacterSet.decimalDigits.union(CharacterSet(charactersIn: numberFormatter.decimalSeparator))
let characterSet = CharacterSet(charactersIn: string)
// False if string contains not allowed characters
if !allowedCharacters.isSuperset(of: characterSet) {
return false
}
// Check for decimal separator
if let input = textField.text {
if let range = input.range(of: numberFormatter.decimalSeparator) {
let endIndex = input.index(input.startIndex, offsetBy: input.distance(from: input.startIndex, to: range.upperBound))
let decimals = input.substring(from: endIndex)
// If the replacement string contains a decimal seperator and there is already one, return false
if input.contains(numberFormatter.decimalSeparator) && string == numberFormatter.decimalSeparator {
return false
}
// If a replacement string is before the separator then true
if replacementStringRange.location < endIndex.encodedOffset {
return true
} else {
// If the string will exceed the max number of fraction digits, then return false, else true
return string.count + decimals.count <= numberFormatter.maximumFractionDigits
}
}
}
return true
}
还有textfield委托方法:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return Utils.validateDecimalNumberText(for: textField, replacementStringRange: range, string: string)
}
答案 13 :(得分:0)
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if (range.location == 0 && string == ".") {
return false
}
else if string == "."{
if textField.text?.componentsSeparatedByString(".").count > 1{
return false
}
}
let aSet = NSCharacterSet(charactersInString:"0123456789.").invertedSet
let compSepByCharInSet = string.componentsSeparatedByCharactersInSet(aSet)
let numberFiltered = compSepByCharInSet.joinWithSeparator("")
return string == numberFiltered
}
答案 14 :(得分:0)
雨燕4 使用@SteveRosenberg的答案并根据我的要求写了这个
最大整数个数为4,即9999,最大十进制数限制为2。因此,最大个数可以为9999.99
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// 100 is the tag value of our textfield
/*or you may use "if textfield == myTextField{" if you have an IBOutlet to that textfield */
if textField.tag == 100 {
//max length limit of text is 8
if textField.text!.count > 8 && string != "" {
return false
}
let maxLength = 8
let currentString: NSString = textField.text! as NSString
// Use following code If you are inputting price to that text field and want $ to get inserted automatically at start when user starts typing in that textfield or you may put some other character at start instead of $. Otherwise comment the following 3 lines of if condition code
if currentString.length == 0 {
priceTextField.text = "$"
}
//new string after inserting the new entered characters
let newString: NSString =
currentString.replacingCharacters(in: range, with: string) as NSString
if newString.length > maxLength{
return false
}
if (textField.text!.range(of: ".") != nil) {
let numStr = newString.components(separatedBy: ".")
if numStr.count>1{
let decStr = numStr[1]
if decStr.length > 2{
return false
}
}
}
var priceStr: String = newString as String
if (textField.text!.range(of: "$") != nil) {
priceStr = priceStr.replacingOccurrences(of: "$", with: "")
}
let price: Double = Double(priceStr) ?? 0
if price > 9999.99{
return false
}
switch string {
case "0","1","2","3","4","5","6","7","8","9":
return true
case ".":
let array = Array(textField.text!)
var decimalCount = 0
for character in array {
if character == "." {
decimalCount = decimalCount + 1
}
}
if decimalCount == 1 {
return false
} else {
return true
}
default:
let array = Array(string)
if array.count == 0 {
return true
}
return false
}
}
return true
}
答案 15 :(得分:0)
Swift 4.2
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let numberCharSet = CharacterSet(charactersIn: ".").union(CharacterSet.decimalDigits)
let characterSet = CharacterSet(charactersIn: string)
return numberCharSet.isSuperset(of: characterSet)
}
这允许从0 to 9
起的数字和小数点.
答案 16 :(得分:0)
如果需要指定小数点,请更改[.,]
。
let regex = try! NSRegularExpression(pattern: "^[0-9]*([.,][0-9]{0,2})?$", options: .caseInsensitive)
if let newText = (textFieldView.textField.text as NSString?)?.replacingCharacters(in: range, with: string) {
return regex.firstMatch(in: newText, options: [], range: NSRange(location: 0, length: newText.count)) != nil
} else {
return false
}
答案 17 :(得分:0)
现在我正在使用不带正则表达式的解决方案。希望对您有帮助:D
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let currentText = (textField.text as NSString?)?.replacingCharacters(in: range, with: string) else { return true }
if textField == txtFieldWeight || textField == txtFieldHeight {
let newText = currentText.replacingOccurrences(of: ",", with: ".")
let isDecimal = Float(newText) != nil
return isDecimal
}
return true
}
答案 18 :(得分:-1)
SWIFT 3.2和4.0 Chis会将用户限制在十进制后的两位数,并限制它们添加一个小数点。 确保将键盘类型设置为十进制。
public func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// if keyboard type is decimal then apply just one dot
if(textField.keyboardType == .decimalPad)
{
// geting counts of dot
let countdots = (textField.text?.components(separatedBy:".").count)! - 1
// if there is more then one dot then
if(countdots > 0)
{
// creating array by dot
var digitArray = textField.text?.components(separatedBy:".")
let decimalDigits = digitArray![1]
// limiting only 2 digits after decimal point
if(decimalDigits.count > 1 )
{
return false;
}
}
// limiting to only 1 decimal point
if countdots > 0 && string == "."
{
return false
}
}
return true
}