引言需求：（輸入框限制輸入多少字符）

1、一個字母、符號、數字相當於一個字符
2、一個漢字相當於兩個字符
3、不能輸入特殊字符
4、不能輸入emoji表情

直接上代碼

一、注冊通知

  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldChange:) name:UITextFieldTextDidChangeNotification object:nil];
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldChange:) name:UITextViewTextDidChangeNotification object:nil];

二、通知實現

- (void)textFieldChange:(UITextField *)textField
{
  //判斷輸入(不能輸入特殊字符)
  [RestrictionInput restrictionInputTextField:self.titleTextField maxNumber:100 showView:self showErrorMessage:@"商品名稱0~100字符~"];
  [RestrictionInput restrictionInputTextView:self.infoTextView maxNumber:200 showView:self showErrorMessage:@"商品描述0~200字符~"];
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
  if ([RestrictionInput isInputRuleAndBlank:text] || [text isEqualToString:@""]) {//當輸入符合規則和退格鍵時允許改變輸入框
    return YES;
  } else {
    return NO;
  }
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
  if ([RestrictionInput isInputRuleAndBlank:string] || [string isEqualToString:@""]) {//當輸入符合規則和退格鍵時允許改變輸入框
    return YES;
  } else {
    return NO;
  }
}

三、封裝類（RestrictionInput）

.h

#import <Foundation/Foundation.h>
@interface RestrictionInput : NSObject
+ (void)restrictionInputTextField:(UITextField *)inputClass maxNumber:(NSInteger)maxNumber showView:(UIView *)showView showErrorMessage:(NSString *)errorMessage;
+ (void)restrictionInputTextView:(UITextView *)inputClass maxNumber:(NSInteger)maxNumber showView:(UIView *)showView showErrorMessage:(NSString *)errorMessage;
+ (BOOL)isInputRuleAndBlank:(NSString *)str;

.m

#import "RestrictionInput.h"
@implementation RestrictionInput
+ (void)restrictionInputTextField:(UITextField *)inputClass maxNumber:(NSInteger)maxNumber showView:(UIView *)showView showErrorMessage:(NSString *)errorMessage
{
  NSString *toBeString = inputClass.text;
  if (![self isInputRuleAndBlank:toBeString]) {
    inputClass.text = [self disable_emoji:toBeString];
    return;
  }
  NSString *lang = [[inputClass textInputMode] primaryLanguage]; // 獲取當前鍵盤輸入模式
  if([lang isEqualToString:@"zh-Hans"]) { //簡體中文輸入,第三方輸入法（搜狗）所有模式下都會顯示“zh-Hans”
    UITextRange *selectedRange = [inputClass markedTextRange];
    //獲取高亮部分
    UITextPosition *position = [inputClass positionFromPosition:selectedRange.start offset:0];
    //沒有高亮選擇的字，則對已輸入的文字進行字數統計和限制
    if(!position) {
      NSString *getStr = [self getSubString:toBeString maxNumber:maxNumber];
      if(getStr && getStr.length > 0) {
        inputClass.text = getStr;
        [showView showHudText:errorMessage hideDelay:1.0 completionBlock:nil];
        NSLog(@"%@", inputClass.text);
      }
    }
  } else{
    NSString *getStr = [self getSubString:toBeString maxNumber:maxNumber];
    if(getStr && getStr.length > 0) {
      inputClass.text= getStr;
      [showView showHudText:errorMessage hideDelay:1.0 completionBlock:nil];
      NSLog(@"%@",inputClass.text);
    }
  }
}
+ (void)restrictionInputTextView:(UITextView *)inputClass maxNumber:(NSInteger)maxNumber showView:(UIView *)showView showErrorMessage:(NSString *)errorMessage
{
  NSString *toBeString = inputClass.text;
  if (![self isInputRuleAndBlank:toBeString]) {
    inputClass.text = [self disable_emoji:toBeString];
    return;
  }
  NSString *lang = [[inputClass textInputMode] primaryLanguage]; // 獲取當前鍵盤輸入模式
  if([lang isEqualToString:@"zh-Hans"]) { //簡體中文輸入,第三方輸入法（搜狗）所有模式下都會顯示“zh-Hans”
    UITextRange *selectedRange = [inputClass markedTextRange];
    //獲取高亮部分
    UITextPosition *position = [inputClass positionFromPosition:selectedRange.start offset:0];
    //沒有高亮選擇的字，則對已輸入的文字進行字數統計和限制
    if(!position) {
      NSString *getStr = [self getSubString:toBeString maxNumber:maxNumber];
      if(getStr && getStr.length > 0) {
        inputClass.text = getStr;
        [showView showHudText:errorMessage hideDelay:1.0 completionBlock:nil];
        NSLog(@"%@", inputClass.text);
      }
    }
  } else{
    NSString *getStr = [self getSubString:toBeString maxNumber:maxNumber];
    if(getStr && getStr.length > 0) {
      inputClass.text= getStr;
      [showView showHudText:errorMessage hideDelay:1.0 completionBlock:nil];
      NSLog(@"%@",inputClass.text);
    }
  }
}
/**
 * 獲得 kMaxLength長度的字符
 */
+ (NSString *)getSubString:(NSString*)string maxNumber:(NSInteger)maxNumber
{
  NSStringEncoding encoding = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
  NSData* data = [string dataUsingEncoding:encoding];
  NSInteger length = [data length];
  if (length > maxNumber) {
    NSData *data1 = [data subdataWithRange:NSMakeRange(0, maxNumber)];
    NSString *content = [[NSString alloc] initWithData:data1 encoding:encoding];//【注意4】：當截取kMaxLength長度字符時把中文字符截斷返回的content會是nil
    if (!content || content.length == 0) {
      data1 = [data subdataWithRange:NSMakeRange(0, maxNumber - 1)];
      content = [[NSString alloc] initWithData:data1 encoding:encoding];
    }
    return content;
  }
  return nil;
}
/**
 * 字母、數字、中文正則判斷（不包括空格）
 */
+ (BOOL)isInputRuleNotBlank:(NSString *)str {
  NSString *pattern = @"^[➋➌➍➎➏➐➑➒\a-zA-Z\u4E00-\u9FA5\\d]*$";
  NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
  BOOL isMatch = [pred evaluateWithObject:str];
  return isMatch;
}
/**
 * 字母、數字、中文正則判斷（包括空格）【注意3】
 */
+ (BOOL)isInputRuleAndBlank:(NSString *)str {
  //九宮格無法輸入解決需要加上正則 \➋➌➍➎➏➐➑➒
  NSString *pattern = @"^[➋➌➍➎➏➐➑➒\a-zA-Z\u4E00-\u9FA5\\d\\s]*$";
  NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
  BOOL isMatch = [pred evaluateWithObject:str];
  return isMatch;
}
+ (NSString *)disable_emoji:(NSString *)text{
  NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"[^\\u0020-\\u007E\\u00A0-\\u00BE\\u2E80-\\uA4CF\\uF900-\\uFAFF\\uFE30-\\uFE4F\\uFF00-\\uFFEF\\u0080-\\u009F\\u2000-\\u201f\r\n]"options:NSRegularExpressionCaseInsensitive error:nil];
  NSString *modifiedString = [regex stringByReplacingMatchesInString:text
                                options:0
                                 range:NSMakeRange(0, [text length])
                             withTemplate:@""];
  return modifiedString;
}

以上所述是小編給大家介紹的iOS UITextField、UITextView只限輸入中文、英文、數字及實時限制字符個數封裝實現，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對本站網站的支持！