iOS 所有对textField的变态限制

限制输入金额的输入框 支付时输入框

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSIndexPath *amountIndexPath = nil;
    if (self.accountBookmodel)
    {
        amountIndexPath = [NSIndexPath indexPathForRow:0 inSection:2];
    }else
    {
        amountIndexPath = [NSIndexPath indexPathForRow:0 inSection:1];
    }
    //NSIndexPath *amountIndexPath = [NSIndexPath indexPathForRow:0 inSection:2];
    LHChargeAccountTableViewCell *amountCell = [self.tableView cellForRowAtIndexPath:amountIndexPath];

    
    if (textField == amountCell.detailTextField) {
        
        _isHaveDian=NO;
        if ([textField.text rangeOfString:@"."].location!=NSNotFound) {
            _isHaveDian = YES;
        }
        if ([textField.text rangeOfString:@"0"].location==NSNotFound) {
            _isFirstZero = NO;
        }
        
        if ([string length]>0)
        {
            unichar single=[string characterAtIndex:0];//当前输入的字符
            if ((single >='0' && single<='9') || single=='.')//数据格式正确
            {
                if ([textField.text length] > 15)
                {
                    return NO;
                }
                if([textField.text length]==0){
                    if(single == '.'){
                        //首字母不能为小数点
                        return NO;
                    }
                    if (single == '0') {
                        _isFirstZero = YES;
                        return YES;
                    }
                }
                
                if (single=='.'){
                    if(!_isHaveDian)//text中还没有小数点
                    {
                        _isHaveDian=YES;
                        return YES;
                    }else{
                        return NO;
                    }
                }else if(single=='0'){
                    if ((_isFirstZero&&_isHaveDian)||(!_isFirstZero&&_isHaveDian)) {
                        //首位有0有.（0.01）或首位没0有.（10200.00）可输入两位数的0
                        if([textField.text isEqualToString:@"0.0"]){
                            return NO;
                        }
                        NSRange ran=[textField.text rangeOfString:@"."];
                        int tt=(int)(range.location-ran.location);
                        if (tt <= 2){
                            return YES;
                        }else{
                            return NO;
                        }
                    }else if (_isFirstZero&&!_isHaveDian){
                        //首位有0没.不能再输入0
                        return NO;
                    }else{
                        return YES;
                    }
                }else{
                    if (_isHaveDian){
                        //存在小数点，保留两位小数
                        NSRange ran=[textField.text rangeOfString:@"."];
                        int tt= (int)(range.location-ran.location);
                        if (tt <= 2){
                            return YES;
                        }else{
                            return NO;
                        }
                    }else if(_isFirstZero&&!_isHaveDian){
                        //首位有0没点
                        return NO;
                    }else{
                        return YES;
                    }
                }
            }else{
                //输入的数据格式不正确
                return NO;
            }
        }else{
            return YES;
        }
    }
    return YES;
}

限制textField输入字数 包含中文、字母

- (void)tfDidChange:(UITextField *)textField
{
    NSInteger max_length = 10;
    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 > max_length)
            {
                textField.text = [toBeString substringToIndex:max_length];
            }
        }
        
    }
    // 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 > max_length)
        {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:max_length];
            if (rangeIndex.length == 1)
            {
                textField.text = [toBeString substringToIndex:max_length];
            }
            else
            {
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, max_length)];
                textField.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}

普通字母 输入限制

- (void)tfDidChange:(UITextField *)textField
{
    if (textField == _phoneTextField) {
        if (textField.text.length > 11)
        {
            [MyAlert showMsg:@"联系方式最多能输入11位" cancelDelay:1.5];
            textField.text = [textField.text substringToIndex:11];
        }
    }
}

限制输入字母+数字 不能输入标点

-(BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString*)string{
    if (_myIndexPath.row == 2) {
        
        NSUInteger lengthOfString = string.length;
        //lengthofstring的值始终是1
        for (NSInteger loopIndex = 0; loopIndex < lengthOfString; loopIndex++) {
            unichar character = [string characterAtIndex:loopIndex];
            //将输入的值转化为ASCII值（即内部索引值），可以参考ASCII表

            // 48-57;{0,9};65-90;{A..Z};97-122:{a..z}
            if (character < 48) {
                return NO;
            }
            if (character > 57 && character < 65) {
                return NO;
            }
            if (character > 90 && character < 97) {
                return NO;
            }
            if (character > 122) {
                return NO;
            }
        }
        
        //限制长度
        NSUInteger proposedNewLenght = textField.text.length - range.length + string.length;
        if (proposedNewLenght > 18) {
            [MyAlert showMsg:@"纳税人识别号不能超过18位" cancelDelay:1];
            return NO;
        }
        return YES;
    }
    return YES;
}

小写字母转大写字母

- (void)textFieldDidEndEditing:(UITextField *)textField {
    textField.text = [textField.text uppercaseString];
}

禁止输入空格

- (void)textFieldChange:(UITextField *)textField
{
    textField.text =[textField.text stringByReplacingOccurrencesOfString:@" " withString:@""];
}

去除字符串前后空格

NSString *str  = @"   ds re 43   ";
str = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
//替换后的str：@"ds re 43"

限制开头不能输入空格

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if ([string isEqualToString:@" "])
    {
        return NO;
    }
    return YES;
}

限制textView输入字数 包含字数提示_statusLabel

- (void)textViewDidChangeSelection:(UITextView *)textView{
    
    NSInteger maxLength = 30;
    NSString *toBeString = textView.text;
    NSString *lang = [textView.textInputMode primaryLanguage];
    if ([lang isEqualToString:@"zh-Hans"]) {// 简体中文输入，包括简体拼音，健体五笔，简体手写
        UITextRange *selectedRange = [textView markedTextRange];
        UITextPosition *position = [textView 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 > maxLength) {
                textView.text = [toBeString substringToIndex:maxLength];
            }
            self.numLabel.text = [NSString stringWithFormat:@"%lu/30",textView.text.length];
        }
        // 有高亮选择的字符串，则暂不对文字进行统计和限制
        else{
        }
    }else {// 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
        if (toBeString.length > maxLength) {
            textView.text = [toBeString substringToIndex:maxLength];
        }
        self.numLabel.text = [NSString stringWithFormat:@"%lu/30",textView.text.length];
    }
}