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限制输入字数

限制输入字数

作者: 心底碎片 | 来源:发表于2016-08-24 16:31 被阅读270次

目前我是这么操作的

1.UITextField *Name;

//监听键盘输入
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(NameTextDidChange:) name:@"UITextFieldTextDidChangeNotification" object:_Name];

注:name一定不能随便改,不然调不到事件

#pragma mark 限制名字的最大长度4
- (void)NameTextDidChange:(NSNotification *)obj{
    UITextField *textField = (UITextField *)obj.object;
    NSString *toBeString = textField.text;
    NSString *lang = [textField.textInputMode primaryLanguage];
    if ([lang isEqualToString:@"zh-Hans"])// 简体中文输入
    {
        //获取高亮部分
        UITextRange *selectedRange = [textField markedTextRange];
        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)
        {
            if (toBeString.length > 4)
            {
                textField.text = [toBeString substringToIndex:4];
            }
        }
        
    }
    // 中文输入法以外的直接对其统计限制即可,不考虑其他语种情况
    else
    {
        if (toBeString.length > 4)
        {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:4];
            if (rangeIndex.length == 1)
            {
                textField.text = [toBeString substringToIndex:4];
            }
            else
            {
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, 4)];
                textField.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}

2.UITextView *QianMing;

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(QianMingTextDidChange:) name:@"UITextViewTextDidChangeNotification" object:_QianMing];
#pragma mark 限制签名的最大长度100
- (void)QianMingTextDidChange:(NSNotification *)obj{
    UITextView * textView = (UITextView *)obj.object;
    NSString * toBeString = textView.text;
    NSString * lang = [textView.textInputMode primaryLanguage];
    if ([lang isEqualToString:@"zh-Hans"]) {//简体中文
        //获取高亮部分
        UITextRange * selectRange = [textView markedTextRange];
        UITextPosition * position = [textView positionFromPosition:selectRange.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) {
            if (toBeString.length > MAX_LENGTH) {
                textView.text = [toBeString substringToIndex:MAX_LENGTH];
            }
        }
    }else{//中文输入法以外直接对其统计限制即可,不考虑其他语种情况
        if (toBeString.length > MAX_LENGTH) {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_LENGTH];
            if (rangeIndex.length == 1) {
                textView.text = [toBeString substringToIndex:MAX_LENGTH];
            }else{
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_LENGTH)];
                textView.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}

这是以前写的

- (void)viewDidLoad {
    [super viewDidLoad];
    [self.TextField addTarget:self action:@selector(textFieldChanged:) forControlEvents:UIControlEventEditingChanged];
    self.TextField.delegate = self;
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    return YES;
}
- (void)textFieldChanged:(UITextField *)textField{
    NSString * toBeString = textField.text;
    if (![self isINputRuleAndBlank:toBeString]) {
        textField.text = [self disable_emoji:toBeString];
        return;
    }
    //获取当前键盘输入模式
    NSString * lang = [[textField textInputMode] primaryLanguage];
    NSLog(@"%@", lang);
    if ([lang isEqualToString:@"zh-hans"]) {
        //简体中文,第三方输入法,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\\d]*$";
    NSPredicate * pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:str];
    return isMatch;
}
/**
 *字母,数字,中文正则判断(包括空格)(在系统输入法中文输入时会出现拼音之间有空格,需要忽略,当按return键时会自动用字母替换,按空格输入响应汉字)
 */
- (BOOL)isINputRuleAndBlank:(NSString *)str {
    NSString * pattern = @"^[a-zA-Z\u4E00-\u9FA5\\d\\s]*$";
    NSPredicate * pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:str];
    return isMatch;
}
/**
 *
 */
- (NSString *)getSubString:(NSString *)str {
    NSStringEncoding encoding = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    NSData * data = [str dataUsingEncoding:encoding];
    NSInteger length = [data length];
    if (length > MAXLEGTH) {
        NSData * data1 = [data subdataWithRange:NSMakeRange(0, MAXLEGTH)];
        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, MAXLEGTH - 1)];
            content = [[NSString alloc] initWithData:data1 encoding:encoding];
        }
        return content;
    }
    return nil;
}
- (NSString *)disable_emoji:(NSString *)str{
    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:str options:0 range:NSMakeRange(0, str.length) withTemplate:@""];
    return modifiedString;
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [self.view endEditing:YES];
}

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