Question

如何验证UITextField的字符串输入？我想检查字符串是否为数字，包括小数点。

Answer 1

你可以这样做几行：

BOOL valid;
NSCharacterSet *alphaNums = [NSCharacterSet decimalDigitCharacterSet];
NSCharacterSet *inStringSet = [NSCharacterSet characterSetWithCharactersInString:myInputField.text];
valid = [alphaNums isSupersetOfSet:inStringSet];    
if (!valid) // Not numeric

- 这是用于验证输入仅为数字字符。查看NSCharacterSet的文档以了解其他选项。您可以使用characterSetWithCharactersInString指定任何有效输入字符集。

Answer 2

有几种方法可以做到这一点：

使用NSNumberFormatter的numberFromString：方法。如果它可以正确解析字符串，则返回NSNumber;如果不能，则返回nil。
使用NSScanner
删除任何非数字字符，查看字符串是否仍然匹配
使用正则表达式

IMO，使用像-[NSString doubleValue]之类的东西不是最好的选择，因为@"0.0"和@"abc"的doubleValue都为0. *值方法如果它们都返回0无法正确转换字符串，因此很难区分@"0"的合法字符串和无效字符串。像C strtol函数之类的东西会有同样的问题。

我认为使用NSNumberFormatter是最好的选择，因为它考虑了区域设置（即欧洲的数字@"1,23"，而美国的数字@"1.23"。）

Answer 3

我在我的Mac应用程序中使用此代码，相同或类似的应该与iPhone一起使用。它基于RegexKitLite正则表达式，并在文本无效时将其变为红色。

static bool TextIsValidValue( NSString* newText, double &value )
{
    bool result = false;

    if ( [newText isMatchedByRegex:@"^(?:|0|[1-9]\\d*)(?:\\.\\d*)?$"] ) {
        result = true;
        value = [newText doubleValue];
    }
    return result;
}

- (IBAction) doTextChanged:(id)sender;
{
    double value;
    if ( TextIsValidValue( [i_pause stringValue], value ) ) {
        [i_pause setTextColor:[NSColor blackColor]];
        // do something with the value
    } else {
        [i_pause setTextColor:[NSColor redColor]];
    }
}

Answer 4

如果您希望只允许用户输入数字，您可以使ViewController实现UITextFieldDelegate的一部分并定义此方法：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
  NSString *resultingString = [textField.text stringByReplacingCharactersInRange: range withString: string];

  // The user deleting all input is perfectly acceptable.
  if ([resultingString length] == 0) {
    return true;
  }

  NSInteger holder;

  NSScanner *scan = [NSScanner scannerWithString: resultingString];

  return [scan scanInteger: &holder] && [scan isAtEnd];
}

可能有更有效的方法，但我发现这是一种非常方便的方式。该方法应该很容易适应验证双打或其他：只需使用scanDouble：或类似。

Answer 5

#pragma mark - UItextfield Delegate

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if ([string isEqualToString:@"("]||[string isEqualToString:@")"]) {
        return TRUE;
    }

    NSLog(@"Range ==%d  ,%d",range.length,range.location);
    //NSRange *CURRANGE = [NSString  rangeOfString:string];

    if (range.location == 0 && range.length == 0) {
        if ([string isEqualToString:@"+"]) {
            return TRUE;
        }
    }
    return [self isNumeric:string];
}

-(BOOL)isNumeric:(NSString*)inputString{
    BOOL isValid = NO;
    NSCharacterSet *alphaNumbersSet = [NSCharacterSet decimalDigitCharacterSet];
    NSCharacterSet *stringSet = [NSCharacterSet characterSetWithCharactersInString:inputString];
    isValid = [alphaNumbersSet isSupersetOfSet:stringSet];
    return isValid;
}

Answer 6

以下是一些将Peter Lewis的上述答案（Check that a input to UITextField is numeric only）与NSPredicates结合起来的单行

    #define REGEX_FOR_NUMBERS   @"^([+-]?)(?:|0|[1-9]\\d*)(?:\\.\\d*)?$"
    #define REGEX_FOR_INTEGERS  @"^([+-]?)(?:|0|[1-9]\\d*)?$"
    #define IS_A_NUMBER(string) [[NSPredicate predicateWithFormat:@"SELF MATCHES %@", REGEX_FOR_NUMBERS] evaluateWithObject:string]
    #define IS_AN_INTEGER(string) [[NSPredicate predicateWithFormat:@"SELF MATCHES %@", REGEX_FOR_INTEGERS] evaluateWithObject:string]

Answer 7

对于整数测试，它将是：

- (BOOL) isIntegerNumber: (NSString*)input
{
    return [input integerValue] != 0 || [input isEqualToString:@"0"];
}

Answer 8

您可以使用字符串的doubleValue，如

NSString *string=@"1.22";
double a=[string doubleValue];

我认为如果字符串无效，这将返回一个0.0（它可能会抛出一个异常，在这种情况下你可以抓住它，文档说0.0 tho）。更多信息here

Answer 9

你有完全相同的问题，我没有看到我用过的答案，所以在这里。

我通过IB创建并连接了我的文本字段。当我通过Control + Drag将它连接到我的代码时，我选择了Action，然后选择了Editing Changed事件。这会在每个字符条目上触发该方法。您可以使用其他事件来适应。

之后，我使用这个简单的代码来替换文本。请注意，我创建了自己的字符集以包含小数/句点字符和数字。基本上将无效字符上的字符串分开，然后用空字符串重新加入它们。

- (IBAction)myTextFieldEditingChangedMethod:(UITextField *)sender {
        NSCharacterSet *validCharacterSet = [NSCharacterSet characterSetWithCharactersInString:@".0123456789"];
        NSCharacterSet *invalidCharacterSet = validCharacterSet.invertedSet;
        sender.text = [[sender.text componentsSeparatedByCharactersInSet:invalidCharacterSet] componentsJoinedByString:@""];
}

现金： Remove all but numbers from NSString

Answer 10

游戏的后期但这里有一个方便的小类我用它来计算小数位和用于它的本地符号。链接到其要点here

@interface NSString (Extension)

- (BOOL) isAnEmail;
- (BOOL) isNumeric;

@end

@implementation NSString (Extension)

/**
 *  Determines if the current string is a valid email address.
 *
 *  @return BOOL - True if the string is a valid email address.
 */

- (BOOL) isAnEmail
{
    NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

    return [emailTest evaluateWithObject:self];
}

/**
 *  Determines if the current NSString is numeric or not. It also accounts for the localised (Germany for example use "," instead of ".") decimal point and includes these as a valid number.
 *
 *  @return BOOL - True if the string is numeric.
 */

- (BOOL) isNumeric
{
    NSString *localDecimalSymbol = [[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator];
    NSMutableCharacterSet *decimalCharacterSet = [NSMutableCharacterSet characterSetWithCharactersInString:localDecimalSymbol];
    [decimalCharacterSet formUnionWithCharacterSet:[NSCharacterSet alphanumericCharacterSet]];

    NSCharacterSet* nonNumbers = [decimalCharacterSet invertedSet];
    NSRange r = [self rangeOfCharacterFromSet: nonNumbers];

    if (r.location == NSNotFound)
    {
        // check to see how many times the decimal symbol appears in the string. It should only appear once for the number to be numeric.
        int numberOfOccurances = [[self componentsSeparatedByString:localDecimalSymbol] count]-1;
        return (numberOfOccurances > 1) ? NO : YES;
    }
    else return NO;
}

@end

Answer 11

IMO实现目标的最佳方法是显示数字键盘而不是普通键盘。这限制了用户可以使用哪些密钥。这减轻了进行验证的需要，更重要的是它可以防止用户犯错误。数字键盘输入数字也更好，因为键数要大得多。

在界面构建器中选择UITextField，转到Attributes Inspector并将“Keyboard Type”更改为“Decimal Pad”。

这会使键盘看起来像这样：

唯一要做的就是确保用户不输入两位小数。您可以在编辑时执行此操作。将以下代码添加到视图控制器。输入后，此代码会删除第二个小数位。用户看起来好像第一个位置没有出现第二个十进制数。

- (void)viewDidLoad
{
  [super viewDidLoad];

  [self.textField addTarget:self
                    action:@selector(textFieldDidChange:)
           forControlEvents:UIControlEventEditingChanged];
}

- (void)textFieldDidChange:(UITextField *)textField
{
  NSString *text = textField.text;
  NSRange range = [text rangeOfString:@"."];

  if (range.location != NSNotFound &&
      [text hasSuffix:@"."] &&
      range.location != (text.length - 1))
  {
    // There's more than one decimal
    textField.text = [text substringToIndex:text.length - 1];
  }
}

Answer 12

@property (strong) NSNumberFormatter *numberFormatter;
@property (strong) NSString *oldStringValue;

- (void)awakeFromNib 
{
  [super awakeFromNib];
  self.numberFormatter = [[NSNumberFormatter alloc] init];
  self.oldStringValue = self.stringValue;
  [self setDelegate:self];
}

- (void)controlTextDidChange:(NSNotification *)obj
{
  NSNumber *number = [self.numberFormatter numberFromString:self.stringValue];
  if (number) {
    self.oldStringValue = self.stringValue;
  } else {
    self.stringValue = self.oldStringValue;
  }
}

Answer 13

旧帖子，但值得一提的是Apple在iOS 4.0中引入了NSRegularExpression。（以彼得的回应中的正则表达式）

// Look for 0-n digits from start to finish
NSRegularExpression *noFunnyStuff = [NSRegularExpression regularExpressionWithPattern:@"^(?:|0|[1-9]\\d*)(?:\\.\\d*)?$" options:0 error:nil];

// There should be just one match
if ([noFunnyStuff numberOfMatchesInString:<#theString#> options:0 range:NSMakeRange(0, <#theString#>.length)] == 1)
{
    // Yay, digits!
}

我建议将NSRegularExpression实例存储在某处。

Answer 14

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if(string.length > 0)
    {
        NSCharacterSet *numbersOnly = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];
        NSCharacterSet *characterSetFromTextField = [NSCharacterSet characterSetWithCharactersInString:string];

        BOOL stringIsValid = [numbersOnly isSupersetOfSet:characterSetFromTextField];
        return stringIsValid;
    }
    return YES;
}

Answer 15

我想要一个只允许整数的文本字段。这是我最终得到的结果（使用此处和其他地方的信息）：

创建整数格式化程序（在UIApplicationDelegate中，以便可以重用）：

@property (nonatomic, retain) NSNumberFormatter *integerNumberFormatter;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Create and configure an NSNumberFormatter for integers
    integerNumberFormatter = [[NSNumberFormatter alloc] init];
    [integerNumberFormatter setMaximumFractionDigits:0];

    return YES;
}

在UITextFieldDelegate中使用过滤器：

@interface MyTableViewController : UITableViewController <UITextFieldDelegate> {
    ictAppDelegate *appDelegate;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    // Make sure the proposed string is a number
    NSNumberFormatter *inf = [appDelegate integerNumberFormatter];
    NSString* proposedString = [textField.text stringByReplacingCharactersInRange:range withString:string];
    NSNumber *proposedNumber = [inf numberFromString:proposedString];
    if (proposedNumber) {
        // Make sure the proposed number is an integer
        NSString *integerString = [inf stringFromNumber:proposedNumber];
        if ([integerString isEqualToString:proposedString]) {
            // proposed string is an integer
            return YES;
        }
    }

    // Warn the user we're rejecting the change
    AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);
    return NO;
}

Answer 16

不那么优雅，但很简单：）

- (BOOL) isNumber: (NSString*)input
{
    return [input doubleValue] != 0 || [input isEqualToString:@"0"] || [input isEqualToString:@"0.0"];
}

Answer 17

在Swift 3中使用单个（。）点与iPad和iPhone一起使用的文本字段中接受小数值

 func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let inverseSet = NSCharacterSet(charactersIn:"0123456789").inverted

        let components = string.components(separatedBy: inverseSet)

        let filtered = components.joined(separator: "")

        if filtered == string {
            return true
        } else {
            if string == "." {
                let countdots = textField.text!.components(separatedBy:".").count - 1
                if countdots == 0 {
                    return true
                }else{
                    if countdots > 0 && string == "." {
                        return false
                    } else {
                        return true
                    }
                }
            }else{
                return false
            }
        }
    }

Answer 18

这个答案如前所述使用NSFormatter。看看：

@interface NSString (NSNumber)
- (BOOL) isNumberWithLocale:(NSLocale *) stringLocale;  
- (BOOL) isNumber;
- (NSNumber *) getNumber; 
- (NSNumber *) getNumberWithLocale:(NSLocale*) stringLocale;
@end

@implementation NSString (NSNumber)
- (BOOL) isNumberWithLocale:(NSLocale *) stringLocale
{
    return [self getNumberWithLocale:stringLocale] != nil;
}
- (BOOL) isNumber
{
    return [ self getNumber ] != nil;
}
- (NSNumber *) getNumber
{
    NSLocale *l_en = [[NSLocale alloc] initWithLocaleIdentifier: @"en_US"] ;  
    return [self getNumberWithLocale: [l_en autorelease] ];
}

- (NSNumber *) getNumberWithLocale:(NSLocale*) stringLocale
{
    NSNumberFormatter *formatter = [[ [ NSNumberFormatter alloc ] init ] autorelease];
    [formatter setLocale: stringLocale ];
    return [ formatter numberFromString:self ]; 
}
@end

我希望它有助于某人。 =）

Answer 19

更加国际化（不仅仅是美国色;-)）只需在上面的代码中替换

-(NSNumber *) getNumber
{
  NSString* localeIdentifier = [[NSLocale autoupdatingCurrentLocale] localeIdentifier];
  NSLocale *l_en = [[NSLocale alloc] initWithLocaleIdentifier: localeIdentifier] ;
  return [self getNumberWithLocale: [l_en autorelease] ];
}

Answer 20

   #import "NSString+Extension.h"

//@interface NSString (Extension)
//
//- (BOOL) isAnEmail;
//- (BOOL) isNumeric;
//
//@end

@implementation NSString (Extension)
 - (BOOL) isNumeric
    {
        NSString *emailRegex = @"[0-9]+";
        NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

        return [emailTest evaluateWithObject:self];

    //    NSString *localDecimalSymbol = [[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator];
    //    NSMutableCharacterSet *decimalCharacterSet = [NSMutableCharacterSet characterSetWithCharactersInString:localDecimalSymbol];
    //    [decimalCharacterSet formUnionWithCharacterSet:[NSCharacterSet alphanumericCharacterSet]];
    //    
    //    NSCharacterSet* nonNumbers = [decimalCharacterSet invertedSet];
    //    NSRange r = [self rangeOfCharacterFromSet: nonNumbers];
    //    
    //    if (r.location == NSNotFound)
    //    {
    //        // check to see how many times the decimal symbol appears in the string. It should only appear once for the number to be numeric.
    //        int numberOfOccurances = [[self componentsSeparatedByString:localDecimalSymbol] count]-1;
    //        return (numberOfOccurances > 1) ? NO : YES;
    //    }
    //    else return NO;
    }

Answer 21

在Swift 4中：

let formatString = "12345"
if let number = Decimal(string:formatString){

    print("String contains only number")
}
else{
    print("String doesn't contains only number")
}

Answer 22

这包括：小数部分控制（包括允许的小数位数），复制/粘贴控制，国际分隔符。

步骤：

确保您的视图控制器继承自UITextFieldDelegate

class MyViewController：UIViewController，UITextFieldDelegate {...
在viewDidLoad中，将控件委托设置为self：

覆盖func viewDidLoad（）{ super.viewDidLoad（）; yourTextField.delegate = self }
实施以下方法并更新＆＃34; decsAllowed＆＃34;常数与所需的小数位数或0如果你想要一个自然数。

Swift 4

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    let decsAllowed: Int = 2
    let candidateText = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
    let decSeparator: String = NumberFormatter().decimalSeparator!;

    let splitted = candidateText.components(separatedBy: decSeparator)
    let decSeparatorsFound = splitted.count - 1
    let decimalPart = decSeparatorsFound > 0 ? splitted.last! : ""
    let decimalPartCount = decimalPart.characters.count

    let characterSet = NSMutableCharacterSet.decimalDigit()
    if decsAllowed > 0 {characterSet.addCharacters(in: decSeparator)}

    let valid = characterSet.isSuperset(of: CharacterSet(charactersIn: candidateText)) &&
                decSeparatorsFound <= 1 &&
                decsAllowed >= decimalPartCount

    return valid
}

如果之后您需要将该字符串安全地转换为数字，您可以使用Double（yourstring）或Int（yourstring）类型转换，或更具学术性的方式：

let formatter = NumberFormatter()
let theNumber: NSNumber = formatter.number(from: yourTextField.text)!

检查UITextField的输入是否仅为数字

22 个答案:

Swift 4