限制TextField只能输入文字英文或数字

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遇到一个需求，就像需要填写企业名称，但是企业名称只能输入中文，英文或者数字，上网百度了一下，需要用到正则效验！！上网搜到一篇大神的文章，但是有点bug，也是解决这个需求，就是系统的9宫格不知为啥不能用了，我改了一下，完美了，感谢一下大神~大神的链接在此 !!感谢感谢！！！

话不多说，上代码

1. 添加代理及文本输入变化通知UIControlEventEditingChanged

#define kMaxLength 20
[_nameTextfield addTarget:self action:@selector(textFieldChanged:) forControlEvents:UIControlEventEditingChanged];
    
    _nameTextfield.delegate = self ;

2.实现以下代理及通知

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    
    if ([self isInputRuleNotBlank:string] || [string isEqualToString:@""]) {//当输入符合规则和退格键时允许改变输入框
        return YES;
    } else {
        return NO;
    }
}
- (void)textFieldChanged:(UITextField *)textField {
    
    
    NSString *toBeString = textField.text;
    
    if (![self isInputRuleAndBlank:toBeString]) {
        textField.text = [self disable_emoji:toBeString];
        return;
    }
    
    NSString *lang = [[textField textInputMode] primaryLanguage]; // 获取当前键盘输入模式
    NSLog(@"%@",lang);
    if([lang isEqualToString:@"zh-Hans"]) { //简体中文输入,第三方输入法（搜狗）所有模式下都会显示“zh-Hans”
        UITextRange *selectedRange = [textField markedTextRange];
        //获取高亮部分
        UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
        //没有高亮选择的字，则对已输入的文字进行字数统计和限制
        if(!position) {
            NSString *getStr = [self getSubString:toBeString];
            if(getStr && getStr.length > 0) {
                textField.text = getStr;
            }
        }
    } else{
        NSString *getStr = [self getSubString:toBeString];
        if(getStr && getStr.length > 0) {
            textField.text= getStr;
        }
    }
}
/**
 * 字母、数字、中文正则判断（不包括空格）
 */
- (BOOL)isInputRuleNotBlank:(NSString *)str {
    NSString *pattern = @"^[a-zA-Z\u4E00-\u9FA5\\d➋➌➍➎➏➐➑➒]*$";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:str];
    return isMatch;
}
/**
 * 字母、数字、中文正则判断（包括空格）（在系统输入法中文输入时会出现拼音之间有空格，需要忽略，当按return键时会自动用字母替换，按空格输入响应汉字）
 */
- (BOOL)isInputRuleAndBlank:(NSString *)str {
    
    NSString *pattern = @"^[a-zA-Z\u4E00-\u9FA5\\d\\s]*$";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:str];
    return isMatch;
}
/**
 *  获得 kMaxLength长度的字符
 */
-(NSString *)getSubString:(NSString*)string
{
    NSStringEncoding encoding = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    NSData* data = [string dataUsingEncoding:encoding];
    NSInteger length = [data length];
    if (length > kMaxLength) {
        NSData *data1 = [data subdataWithRange:NSMakeRange(0, kMaxLength)];
        NSString *content = [[NSString alloc] initWithData:data1 encoding:encoding];//注意：当截取kMaxLength长度字符时把中文字符截断返回的content会是nil
        if (!content || content.length == 0) {
            data1 = [data subdataWithRange:NSMakeRange(0, kMaxLength - 1)];
            content =  [[NSString alloc] initWithData:data1 encoding:encoding];
        }
        return content;
    }
    return nil;
}
- (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;
}

上述demo在此,限制UITextView的字数和字数监控，表情异常的情况和禁用表情请看飞向云端的鱼