引言需求：（輸入框限制輸入多少字符）
1、一個字母、符號、數字相當于一個字符
2、一個漢字相當于兩個字符
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武林網網站的支持！
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