限制 Text Field 输入的内容类型：只允许输入数字

效果如下：

 

ViewController.h

1 #import <UIKit/UIKit.h>

2 

3 @interface ViewController : UIViewController<UITextFieldDelegate>

4 @property (strong, nonatomic) IBOutlet UITextField *txtLimitInput;

5 

6 @end

ViewController.m

  1 #import "ViewController.h"

  2 

  3 @interface ViewController ()

  4 - (void)layoutUI;

  5 - (BOOL)validateNumberByASCII:(NSString *)string;

  6 - (BOOL)validateNumberByRange:(NSString *)string;

  7 - (BOOL)validateNumberByRegExp:(NSString *)string;

  8 @end

  9 

 10 @implementation ViewController

 11 

 12 - (void)viewDidLoad {

 13     [super viewDidLoad];

 14     

 15     [self layoutUI];

 16 }

 17 

 18 - (void)didReceiveMemoryWarning {

 19     [super didReceiveMemoryWarning];

 20     // Dispose of any resources that can be recreated.

 21 }

 22 

 23 - (void)layoutUI {

 24     _txtLimitInput.placeholder = @"请输入数字";

 25     

 26     //第一种方式：设置键盘类型

 27     //_txtLimitInput.keyboardType = UIKeyboardTypeDecimalPad;

 28     

 29     //第二种方式：通过 UITextFieldDelegate 的 shouldChangeCharactersInRange: 方法

 30     _txtLimitInput.delegate = self;

 31 }

 32 

 33 #pragma mark - 三种判断字符串内容是否是有效数字的方式

 34 /**

 35  *  『ASCII码』判断字符串内容是否是有效数字

 36  *

 37  *  @param string 需要验证的字符串

 38  *

 39  *  @return 字符串内容是否是有效数字

 40  */

 41 - (BOOL)validateNumberByASCII:(NSString *)string {

 42     BOOL isValid = YES;

 43     NSUInteger len = string.length;

 44     if (len > 0) {

 45         for (NSUInteger i=0; i<len; i++) {

 46             NSUInteger asciiCode = [string characterAtIndex:i];

 47             if (asciiCode < 48 || asciiCode > 57) {

 48                 isValid = NO;

 49                 break;

 50             }

 51         }

 52     }

 53     return isValid;

 54 }

 55 

 56 /**

 57  *  『字符范围』判断字符串内容是否是有效数字

 58  *

 59  *  @param string 需要验证的字符串

 60  *

 61  *  @return 字符串内容是否是有效数字

 62  */

 63 - (BOOL)validateNumberByRange:(NSString *)string {

 64     BOOL isValid = YES;

 65     NSUInteger len = string.length;

 66     if (len > 0) {

 67         NSCharacterSet *validNumberCS = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];

 68         NSUInteger singleStrIndex = 0;

 69         do {

 70             NSString *singleStr = [string substringWithRange:NSMakeRange(singleStrIndex, 1)];

 71             NSRange range = [singleStr rangeOfCharacterFromSet:validNumberCS];

 72             if (range.length == 0) {

 73                 isValid = NO;

 74                 break;

 75             }

 76             singleStrIndex++;

 77         } while (singleStrIndex < len);

 78     }

 79     return isValid;

 80 }

 81 

 82 /**

 83  *  『正则表达式；推荐使用，不用循环遍历，控制更灵活』判断字符串内容是否是有效数字

 84  *

 85  *  @param string 需要验证的字符串

 86  *

 87  *  @return 字符串内容是否是有效数字

 88  */

 89 - (BOOL)validateNumberByRegExp:(NSString *)string {

 90     BOOL isValid = YES;

 91     NSUInteger len = string.length;

 92     if (len > 0) {

 93         NSString *numberRegex = @"^[0-9]*$";

 94         NSPredicate *numberPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", numberRegex];

 95         isValid = [numberPredicate evaluateWithObject:string];

 96     }

 97     return isValid;

 98 }

 99 

100 #pragma mark - UITextFieldDelegate

101 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

102     //return [self validateNumberByASCII:string];

103     //return [self validateNumberByRange:string];

104     return [self validateNumberByRegExp:string]; //推荐方式

105 }

106 

107 @end

Main.storyboard

 1 <?xml version="1.0" encoding="UTF-8" standalone="no"?>

 2 <document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="7706" systemVersion="14E46" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="vXZ-lx-hvc">

 3     <dependencies>

 4         <deployment identifier="iOS"/>

 5         <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="7703"/>

 6     </dependencies>

 7     <scenes>

 8         <!--View Controller-->

 9         <scene sceneID="ufC-wZ-h7g">

10             <objects>

11                 <viewController id="vXZ-lx-hvc" customClass="ViewController" sceneMemberID="viewController">

12                     <layoutGuides>

13                         <viewControllerLayoutGuide type="top" id="jyV-Pf-zRb"/>

14                         <viewControllerLayoutGuide type="bottom" id="2fi-mo-0CV"/>

15                     </layoutGuides>

16                     <view key="view" contentMode="scaleToFill" id="kh9-bI-dsS">

17                         <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>

18                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>

19                         <subviews>

20                             <textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" borderStyle="roundedRect" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="mb3-C5-UpN">

21                                 <rect key="frame" x="200" y="285" width="200" height="30"/>

22                                 <constraints>

23                                     <constraint firstAttribute="width" constant="200" id="8dl-R0-OzV"/>

24                                 </constraints>

25                                 <fontDescription key="fontDescription" type="system" pointSize="14"/>

26                                 <textInputTraits key="textInputTraits"/>

27                             </textField>

28                             <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="限制 Text Field 输入的内容类型" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="8zf-7E-ija">

29                                 <rect key="frame" x="200" y="255" width="196" height="17"/>

30                                 <fontDescription key="fontDescription" type="system" pointSize="14"/>

31                                 <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="calibratedRGB"/>

32                                 <nil key="highlightedColor"/>

33                             </label>

34                         </subviews>

35                         <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>

36                         <constraints>

37                             <constraint firstItem="mb3-C5-UpN" firstAttribute="centerX" secondItem="kh9-bI-dsS" secondAttribute="centerX" id="Dh5-bw-2LN"/>

38                             <constraint firstItem="mb3-C5-UpN" firstAttribute="centerY" secondItem="kh9-bI-dsS" secondAttribute="centerY" id="Lby-hq-mya"/>

39                             <constraint firstItem="mb3-C5-UpN" firstAttribute="leading" secondItem="8zf-7E-ija" secondAttribute="leading" id="SyI-SC-iNN"/>

40                             <constraint firstItem="mb3-C5-UpN" firstAttribute="top" secondItem="8zf-7E-ija" secondAttribute="bottom" constant="13" id="yuO-kC-OCZ"/>

41                         </constraints>

42                     </view>

43                     <connections>

44                         <outlet property="txtLimitInput" destination="mb3-C5-UpN" id="cYi-Ep-sWq"/>

45                     </connections>

46                 </viewController>

47                 <placeholder placeholderIdentifier="IBFirstResponder" id="x5A-6p-PRh" sceneMemberID="firstResponder"/>

48             </objects>

49         </scene>

50     </scenes>

51 </document>