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。
:@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。
– (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];(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:NSStringEnumerationByComposedCharacterSequencesusingBlock: ^(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;{contentWidth = CGRectGetWidth(textView.frame);+ textView.contentInset.right+ textView.textContainerInset.left+ textView.textContainerInset.right+ textView+ textView);CGFloat broadHeight = (textView.contentInset.top+ textView.contentInset.bottom+ textView.textContainerInset.top+ textViewcontentWidth -= 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{&& (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];(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:NSStringEnumerationByComposedCharacterSequencesusingBlock: ^(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];= [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];}= [NSString stringWithFormat:@”%ld/%d”,MAX(0,MAX_LIMIT_NUMS – existTextNum),MAX_LIMIT_NUMS];[self refreshTextViewSize:textView];}公用方法送给中意的TA，背面写上：某年某月某日，
