我有一个 UITextField，单击它会在左下角显示一个带小数点的数字键盘。我正在尝试限制该字段，以便用户只能放置 1 个小数点
例如
2.5 OK
2..5 NOT OK
问问题
21674 次
16 回答
43
像这样实现 shouldChangeCharactersInRange 方法：
// Only allow one decimal point
// Example assumes ARC - Implement proper memory management if not using.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
NSArray *arrayOfString = [newString componentsSeparatedByString:@"."];
if ([arrayOfString count] > 2 )
return NO;
return YES;
}
这将创建一个由小数点分割的字符串数组，因此如果有多个小数点，我们将在数组中至少有 3 个元素。
于 2012-05-01T23:42:01.197 回答
15
这是一个带有正则表达式的示例，该示例仅限于一个小数点和 2 个小数点。您可以对其进行调整以满足您的需求。
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
NSString *expression = @"^[0-9]*((\\.|,)[0-9]{0,2})?$";
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:expression options:NSRegularExpressionCaseInsensitive error:&error];
NSUInteger numberOfMatches = [regex numberOfMatchesInString:newString options:0 range:NSMakeRange(0, [newString length])];
return numberOfMatches != 0;
}
于 2014-01-14T02:56:17.697 回答
8
Swift 3实现此 UITextFieldDelegate 方法以防止用户输入无效数字：
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let text = (textField.text ?? "") as NSString
let newText = text.replacingCharacters(in: range, with: string)
if let regex = try? NSRegularExpression(pattern: "^[0-9]*((\\.|,)[0-9]*)?$", 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。您还可以使用此模式限制小数位数：（"^[0-9]*((\\.|,)[0-9]{0,2})?$"在本例中为 2）。
于 2017-06-21T15:22:31.240 回答
7
斯威夫特 4
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
// Allow to remove character (Backspace)
if string == "" {
return true
}
// Block multiple dot
if (textField.text?.contains("."))! && string == "." {
return false
}
// Check here decimal places
if (textField.text?.contains("."))! {
let limitDecimalPlace = 2
let decimalPlace = textField.text?.components(separatedBy: ".").last
if (decimalPlace?.count)! < limitDecimalPlace {
return true
}
else {
return false
}
}
return true
}
Objective-C
//Create this variable in .h file or .m file
float _numberOfDecimal;
//assign value in viewDidLoad method
numberOfDecimal = 2;
#pragma mark - TextFieldDelegate
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
// Allow to remove character (Backspace)
if ([string isEqualToString:@""]) {
return true;
}
// Block multiple dot
if ([textField.text containsString:@"."] && [string isEqualToString:@"."]) {
return false;
}
// Check here decimal places
if ([textField.text containsString:@"."]) {
NSString *strDecimalPlace = [[textField.text componentsSeparatedByString:@"."] lastObject];
if (strDecimalPlace.length < _numberOfDecimal) {
return true;
}
else {
return false;
}
}
return true;
}
于 2018-08-16T08:59:36.963 回答
6
对于 Swift 2.3 以防止用户在两个位置后输入十进制数字 -
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{
let decimalPlacesLimit = 2
let rangeDot = txtPrice.text!.rangeOfString(".", options: .CaseInsensitiveSearch)
if rangeDot?.count > 0
{
if (string == ".")
{
print("textField already contains a separator")
return false
}
else {
var explodedString = txtPrice.text!.componentsSeparatedByString(".")
let decimalPart = explodedString[1]
if decimalPart.characters.count >= decimalPlacesLimit && !(string == "")
{
print("textField already contains \(decimalPlacesLimit) decimal places")
return false
}
}
}
}
于 2017-02-04T07:06:24.327 回答
5
基于公认的答案，以下方法验证了在处理货币格式时有用的三个案例：
- 数额特别大
- 小数点后2个以上字符
- 多于 1 位小数
确保您的文本字段的委托设置正确，您的类符合UITextField协议，并添加以下委托方法。
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
// Check for deletion of the $ sign
if (range.location == 0 && [textField.text hasPrefix:@"$"])
return NO;
NSString *updatedText = [textField.text stringByReplacingCharactersInRange:range withString:string];
NSArray *stringsArray = [updatedText componentsSeparatedByString:@"."];
// Check for an absurdly large amount
if (stringsArray.count > 0)
{
NSString *dollarAmount = stringsArray[0];
if (dollarAmount.length > 6)
return NO;
}
// Check for more than 2 chars after the decimal point
if (stringsArray.count > 1)
{
NSString *centAmount = stringsArray[1];
if (centAmount.length > 2)
return NO;
}
// Check for a second decimal point
if (stringsArray.count > 2)
return NO;
return YES;
}
于 2014-05-27T19:19:44.160 回答
2
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if(textField == min_textfield )
{
if([textField.text rangeOfString:@"."].location == NSNotFound)
{
if([string isEqualToString:@"."] )
{
flag_for_text = 1;
}
else
{
textField.text = [NSMutableString stringWithFormat:@"%@",textField.text];
}
}
else
{
if([string isEqualToString:@"."])
{
return NO;
}
else
{
textField.text = [NSMutableString stringWithFormat:@"%@",textField.text];
}
}
}
}
于 2012-09-13T05:20:40.307 回答
2
尝试这个 ：-
public func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
if(text == "," || text == "." ){
let countdots = textView.text!.componentsSeparatedByString(".").count - 1
if countdots > 0 && (text == "." || text == "," )
{
return false
}
}
return true
}
于 2016-08-17T05:29:46.807 回答
1
斯威夫特 4
整数的最大数量为 4 即 9999，最大小数位数限制为 2。因此，最大数量可以是 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
// 使用下面的代码 如果您在该文本字段中输入价格并希望在用户开始在该文本字段中输入时自动插入 $，或者您可以在开头放置一些其他字符而不是 $。否则注释以下 3 行 if 条件代码
if currentString.length == 0 {
priceTextField.text = "$"
}
//插入新输入的字符后的新字符串
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
}
于 2018-10-19T12:02:22.750 回答
1
斯威夫特 3
无需创建数组和检查计数。限制用户只能像这样放置 1 个小数点。
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if (textField.text?.contains("."))! && string.contains(".")
{
return false
}
else
{
return true
}
}
于 2017-03-27T07:55:13.047 回答
0
我提出了解决方案，它可以让您控制小数位数，因此用户只能输入一个小数分隔符，您还可以控制小数位数。
只需正确设置decimalPlacesLimit值。
见方法：
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSLog(@"text on the way: %@", string);
NSUInteger decimalPlacesLimit = 2;
NSRange rangeDot = [textField.text rangeOfString:@"." options:NSCaseInsensitiveSearch];
NSRange rangeComma = [textField.text rangeOfString:@"," options:NSCaseInsensitiveSearch];
if (rangeDot.length > 0 || rangeComma.length > 0){
if([string isEqualToString:@"."]) {
NSLog(@"textField already contains a separator");
return NO;
} else {
NSArray *explodedString = [textField.text componentsSeparatedByString:@"."];
NSString *decimalPart = explodedString[1];
if (decimalPart.length >= decimalPlacesLimit && ![string isEqualToString:@""]) {
NSLog(@"textField already contains %d decimal places", decimalPlacesLimit);
return NO;
}
}
}
return YES;
}
于 2014-05-30T06:55:45.080 回答
0
在您将 UITextField 的委托设置为的任何对象中，添加一个响应" [- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string]"的方法。
然后，您可以使用NSNumberFormatter对象，也可以对已经存在的小数点进行暴力检查（NO如果小数点已经存在，则返回）。
于 2012-05-01T20:51:02.900 回答
0
简而言之，数字格式如下[NSString stringWithFormat:@"%9.5f", x];其中 5 是“，”之后的小数。
于 2013-06-17T21:10:25.243 回答
0
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if([string isEqualToString:@"."]) {
BOOL containsDecimal = [textField.text containsString:@"."];
return !containsDecimal;
}
return YES;
}
如果文本字段文本已包含“。” 然后返回 NO 否则返回 YES。
于 2019-03-07T10:39:15.230 回答
0
Swift 4
The efficient and easy way to avoid multiple decimal points (. or ,) in UITextField:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if(string == "," || string == "." ){
if ((textField.text?.contains(","))! || (textField.text?.contains("."))!){
return false
}
}
return true
}
于 2018-05-22T09:34:32.667 回答
0
斯威夫特 5
改进
信息：不允许：
- 开头的分隔符
- 零加另一个数字，除非您在后面添加分隔符
1：设置键盘类型为：Decimal Pad
2：复制过去
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
//!\ set the keyboard type to : Decimal Pad /!\\
// CUSTOM SETUP
let c = NSLocale.current.decimalSeparator ?? "."
let limitBeforeSeparator = 2
let limitAfterSeparator = 2
// ---------
var validatorUserInput:Bool = false
let text = (textField.text ?? "") as NSString
let newText = text.replacingCharacters(in: range, with: string)
// Validator
let pattern = "(?!0[0-9])\\d*(?!\\\(c))^[0-9]{0,\(limitBeforeSeparator)}((\\\(c))[0-9]{0,\(limitAfterSeparator)})?$"
if let regex = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive) {
validatorUserInput = regex.numberOfMatches(in: newText, options: .reportProgress, range: NSRange(location: 0, length: (newText as NSString).length)) > 0
}
if validatorUserInput {
// setting data or something eles before the return
if let char = string.cString(using: String.Encoding.utf8) {
let isBackSpace = strcmp(char, "\\b")
if (isBackSpace == -92 && textField.text?.count == 1) {
print("Backspace was pressed")
print(newText)
// do something...
} else {
print("Number Added")
print(newText)
// do something...
}
}
return validatorUserInput
} else {
return validatorUserInput
}
}
3：方法中设置，如果要x分隔符前后最大位数
let limitBeforeSeparator = 2
let limitAfterSeparator = 2
于 2020-12-15T01:24:00.923 回答