UITextField 限制小数输入金额

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (textField.text.length > 10) {
        return range.location < 11;
    }else{
        BOOL isHaveDian = YES;
        if ([textField.text rangeOfString:@"."].location==NSNotFound) {
            isHaveDian=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
            {
                //首字母不能为小数点
                if([textField.text length]==0){
                    if(single == '.'){
                        [textField.text stringByReplacingCharactersInRange:range withString:@""];
                        return NO;

                    }
                }
                if([textField.text length]==1 && [textField.text isEqualToString:@"0"]){
                    if(single != '.'){
                        [textField.text stringByReplacingCharactersInRange:range withString:@""];
                        return NO;

                    }
                }
                if (single=='.')
                {
                    if(!isHaveDian)//text中还没有小数点
                    {
                        isHaveDian=YES;
                        return YES;
                    }else
                    {
                        [textField.text stringByReplacingCharactersInRange:range withString:@""];
                        return NO;
                    }
                }
                else
                {
                    if (isHaveDian)//存在小数点
                    {
                        //判断小数点的位数
                        NSRange ran=[textField.text rangeOfString:@"."];
                        NSInteger tt=range.location-ran.location;
                        if (tt <= 2){//2表示小数点后能输入两位，4就是能输入4位
                            return YES;
                        }else{
                            return NO;
                        }
                    }
                    else
                    {
                        return YES;
                    }
                }
            }else{//输入的数据格式不正确
                [textField.text stringByReplacingCharactersInRange:range withString:@""];
                return NO;
            }
        }
        else
        {
            return YES;
        }
    }
}