IOS UITextField &UITextView

UITextField

限制textField长度

曾经，以为输入框只是输入字符的，但真的认真为一个登陆界面输入框而改了六七次以后，发现好烦人啊，先谢谢测试的不厌其烦，不杀之恩，不想再用IOS的输入框就是这样子的来敷衍产品汪，认真思考了一下，还真有点不好搞啊，于是呼，找了点测试过能用的代码，贴这里给我们这些菜鸟用，万恶的复制啊，你ctrl v一下，不带走一片云彩。

 [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textFiledEditChanged:)
                                                name:@"UITextFieldTextDidChangeNotification"
                                              object:self.textField];

#define kMaxLength 10
-(void)textFiledEditChanged:(NSNotification *)obj{
    [self setNeedsStatusBarAppearanceUpdate];

    UITextField *textField = (UITextField *)obj.object;

    NSString *toBeString = textField.text;
    NSString *lang = [[[UITextInputMode activeInputModes] firstObject]primaryLanguage]; // 键盘输入模式
    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 = [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) {
            if (toBeString.length > kMaxLength) {
                textField.text = [toBeString substringToIndex:kMaxLength];
            }
        }
        // 有高亮选择的字符串，则暂不对文字进行统计和限制
        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
    else{
        if (toBeString.length > kMaxLength) {
            textField.text = [toBeString substringToIndex:kMaxLength];
        }
    }

}

UITextView

限制textView长度

这个代码着实有点长啊，不过都包含了中，英文字符输入时限制，而且带emoji时截取显示半个或乱码字符也处理一下，看着挺强大了，万恶的复制啊，都别那么懒了，附上原文链接，想研究的，可以去看看http://blog.csdn.net/fengsh998/article/details/45421107。

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range
 replacementText:(NSString *)text
{
    UITextRange *selectedRange = [textView markedTextRange];
    //获取高亮部分
    UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];
    //获取高亮部分内容
    //NSString * selectedtext = [textView textInRange:selectedRange];

    //如果有高亮且当前字数开始位置小于最大限制时允许输入
    if (selectedRange && pos) {
        NSInteger startOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.start];
        NSInteger endOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.end];
        NSRange offsetRange = NSMakeRange(startOffset, endOffset - startOffset);

        if (offsetRange.location < MAX_LIMIT_NUMS) {
            return YES;
        }
        else
        {
            return NO;
        }
    }
    NSString *comcatstr = [textView.text stringByReplacingCharactersInRange:range withString:text];

    NSInteger caninputlen = MAX_LIMIT_NUMS - comcatstr.length;

    if (caninputlen >= 0)
    {
        return YES;
    }
    else
    {
        NSInteger len = text.length + caninputlen;
        //防止当text.length + caninputlen < 0时，使得rg.length为一个非法最大正数出错
        NSRange rg = {0,MAX(len,0)};

        if (rg.length > 0)
        {
            NSString *s = @"";
            //判断是否只普通的字符或asc码(对于中文和表情返回NO)
            BOOL asc = [text canBeConvertedToEncoding:NSASCIIStringEncoding];
            if (asc) {
                s = [text substringWithRange:rg];//因为是ascii码直接取就可以了不会错
            }
            else
            {
                __block NSInteger idx = 0;
                __block NSString  *trimString = @"";//截取出的字串
                                                    //使用字符串遍历，这个方法能准确知道每个emoji是占一个unicode还是两个
                [text enumerateSubstringsInRange:NSMakeRange(0, [text length])
                                         options:NSStringEnumerationByComposedCharacterSequences
                                      usingBlock: ^(NSString* substring, NSRange substringRange, NSRange enclosingRange, BOOL* stop) {

                                          if (idx >= rg.length) {
                                              *stop = YES; //取出所需要就break，提高效率
                                              return ;
                                          }

                                          trimString = [trimString stringByAppendingString:substring];

                                          idx++;
                                      }];

                s = trimString;
            }
            //rang是指从当前光标处进行替换处理(注意如果执行此句后面返回的是YES会触发didchange事件)
            [textView setText:[textView.text stringByReplacingCharactersInRange:range withString:s]];
            //既然是超出部分截取了，哪一定是最大限制了。
//            self.textField.text = [NSString stringWithFormat:@"%d/%ld",0,(long)MAX_LIMIT_NUMS];
        }
        return NO;
    }

}

- (void)textViewDidChange:(UITextView *)textView
{
    UITextRange *selectedRange = [textView markedTextRange];
    //获取高亮部分
    UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

    //如果在变化中是高亮部分在变，就不要计算字符了
    if (selectedRange && pos) {
        return;
    }

    NSString  *nsTextContent = textView.text;
    NSInteger existTextNum = nsTextContent.length;

    if (existTextNum > MAX_LIMIT_NUMS)
    {
        //截取到最大位置的字符(由于超出截部分在should时被处理了所在这里这了提高效率不再判断)
        NSString *s = [nsTextContent substringToIndex:MAX_LIMIT_NUMS];

        [textView setText:s];
    }

    //不让显示负数 口口日
//    self.textField.text = [NSString stringWithFormat:@"%ld/%d",MAX(0,MAX_LIMIT_NUMS - existTextNum),MAX_LIMIT_NUMS];
}

UITextView的动态适应高度处理

- (CGSize)getStringRectInTextView:(NSString *)string InTextView:(UITextView *)textView;
{
    //
    //    NSLog(@"行高  ＝ %f container = %@,xxx = %f",self.textview.font.lineHeight,self.textview.textContainer,self.textview.textContainer.lineFragmentPadding);
    //
    //实际textView显示时我们设定的宽
    CGFloat contentWidth = CGRectGetWidth(textView.frame);
    //但事实上内容需要除去显示的边框值
    CGFloat broadWith    = (textView.contentInset.left + textView.contentInset.right
                            + textView.textContainerInset.left
                            + textView.textContainerInset.right
                            + textView.textContainer.lineFragmentPadding/*左边距*/
                            + textView.textContainer.lineFragmentPadding/*右边距*/);

    CGFloat broadHeight  = (textView.contentInset.top
                            + textView.contentInset.bottom
                            + textView.textContainerInset.top
                            + textView.textContainerInset.bottom);//+self.textview.textContainer.lineFragmentPadding/*top*//*+theTextView.textContainer.lineFragmentPadding*//*there is no bottom padding*/);

    //由于求的是普通字符串产生的Rect来适应textView的宽
    contentWidth -= broadWith;

    CGSize InSize = CGSizeMake(contentWidth, MAXFLOAT);

    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
    paragraphStyle.lineBreakMode = textView.textContainer.lineBreakMode;
    NSDictionary *dic = @{NSFontAttributeName:textView.font, NSParagraphStyleAttributeName:[paragraphStyle copy]};

    CGSize calculatedSize =  [string boundingRectWithSize:InSize options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:dic context:nil].size;

    CGSize adjustedSize = CGSizeMake(ceilf(calculatedSize.width),calculatedSize.height + broadHeight);//ceilf(calculatedSize.height)
    return adjustedSize;
}

- (void)refreshTextViewSize:(UITextView *)textView
{
    CGSize size = [self getStringRectInTextView:textView.text InTextView:textView];//[textView sizeThatFits:CGSizeMake(CGRectGetWidth(textView.frame), MAXFLOAT)];
    if (self.autoAdpterRect && (size.height > CGRectGetHeight(textView.frame)))
    {
        CGRect frame = textView.frame;
        frame.size.height = size.height;
        textView.frame = frame;
    }
}

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range
 replacementText:(NSString *)text
{
    //对于退格删除键开放限制
    if (text.length == 0) {
        return YES;
    }

    UITextRange *selectedRange = [textView markedTextRange];
    //获取高亮部分
    UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];
    //获取高亮部分内容
    //NSString * selectedtext = [textView textInRange:selectedRange];

    //如果有高亮且当前字数开始位置小于最大限制时允许输入
    if (selectedRange && pos) {
        NSInteger startOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.start];
        NSInteger endOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.end];
        NSRange offsetRange = NSMakeRange(startOffset, endOffset - startOffset);

        if (offsetRange.location < MAX_LIMIT_NUMS) {
            return YES;
        }
        else
        {
            return NO;
        }
    }


    NSString *comcatstr = [textView.text stringByReplacingCharactersInRange:range withString:text];

    NSInteger caninputlen = MAX_LIMIT_NUMS - comcatstr.length;

    if (caninputlen >= 0)
    {
        //加入动态计算高度
        CGSize size = [self getStringRectInTextView:comcatstr InTextView:textView];
        CGRect frame = textView.frame;
        frame.size.height = size.height;

        textView.frame = frame;
        return YES;
    }
    else
    {
        NSInteger len = text.length + caninputlen;
        //防止当text.length + caninputlen < 0时，使得rg.length为一个非法最大正数出错
        NSRange rg = {0,MAX(len,0)};

        if (rg.length > 0)
        {
            NSString *s = @"";
            //判断是否只普通的字符或asc码(对于中文和表情返回NO)
            BOOL asc = [text canBeConvertedToEncoding:NSASCIIStringEncoding];
            if (asc) {
                s = [text substringWithRange:rg];//因为是ascii码直接取就可以了不会错
            }
            else
            {
                __block NSInteger idx = 0;
                __block NSString  *trimString = @"";//截取出的字串
                //使用字符串遍历，这个方法能准确知道每个emoji是占一个unicode还是两个
                [text enumerateSubstringsInRange:NSMakeRange(0, [text length])
                                              options:NSStringEnumerationByComposedCharacterSequences
                                           usingBlock: ^(NSString* substring, NSRange substringRange, NSRange enclosingRange, BOOL* stop) {

                                               NSInteger steplen = substring.length;
                                               if (idx >= rg.length) {
                                                   *stop = YES; //取出所需要就break，提高效率
                                                   return ;
                                               }

                                               trimString = [trimString stringByAppendingString:substring];

                                               idx = idx + steplen;
                                           }];

                s = trimString;
            }
            //rang是指从当前光标处进行替换处理(注意如果执行此句后面返回的是YES会触发didchange事件)
            [textView setText:[textView.text stringByReplacingCharactersInRange:range withString:s]];

            //由于后面反回的是NO不触发didchange
            [self refreshTextViewSize:textView];
            //既然是超出部分截取了，哪一定是最大限制了。
            self.lbNums.text = [NSString stringWithFormat:@"%d/%ld",0,(long)MAX_LIMIT_NUMS];
        }
        return NO;
    }

}


- (void)textViewDidChange:(UITextView *)textView
{
    UITextRange *selectedRange = [textView markedTextRange];
    //获取高亮部分
    UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

    //如果在变化中是高亮部分在变，就不要计算字符了
    if (selectedRange && pos) {
        return;
    }

    NSString  *nsTextContent = textView.text;
    NSInteger existTextNum = nsTextContent.length;

    if (existTextNum > MAX_LIMIT_NUMS)
    {
        //截取到最大位置的字符(由于超出截部分在should时被处理了所在这里这了提高效率不再判断)
        NSString *s = [nsTextContent substringToIndex:MAX_LIMIT_NUMS];

        [textView setText:s];
    }

    //不让显示负数 口口日
    self.lbNums.text = [NSString stringWithFormat:@"%ld/%d",MAX(0,MAX_LIMIT_NUMS - existTextNum),MAX_LIMIT_NUMS];

    [self refreshTextViewSize:textView];
}

公用方法

stringByReplacingCharactersInRange: withString: 實現字符串删除，替换

NSString *str = @"1234567890";  
[str stringByReplacingCharactersInRange:NSMakeRange(str.length-1, 1) withString:@""];  

NSLog(@"str = %@",  str);  // str = 123456789  

[str stringByReplacingCharactersInRange:NSMakeRange(str.length-1, 1) withString:@"1"];  

解释：NSMakeRange(str.length-1, 1),将字符串str定位到第九个字符即‘9’，取长度为1的字符串，即9后第一个字符串 ‘0’，用字符串@“”替代‘0’，即所得的结果为“123456789”