iOS开发中UITextView使用小结

　　最近项目开发中用到了多行文本框限制文字输入个数限制，之前的话在textViewDidChange方法中截取超出字数就可以。测试人员发现在拼音转汉字的过程中，YYTextView不会二次确认textViewDidChange方法，输入字数只能最后确认结束弹框的时候计算，影响体验效果，后转用自己封装的继承UITextView替换。另外拼音转汉字的情况下，在输入文本中间一直输入，依然会出现输入字数计算不准确的问题。下面列出解决问题实现的代码。

　　

#pragma mark- UITextViewDelegate

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

[self.activityTextView resignFirstResponder];

}

-(void)updateSpeechButtonStatus{

if (self.activityTextView.text.length >= MAX_NUM) {

self.btnSpeech.enabled = NO;

}else{

self.btnSpeech.enabled = YES;

}

}

//动态显示可输入文本字数

-(void)changeTextNumber:(UITextView *)textView{

if (textView.text.length <= MAX_NUM) {

self.numLabel.text = [NSString stringWithFormat:@"%lu/%lu",(unsigned long)textView.text.length,(MAX_NUM - textView.text.length)];

}else{

self.numLabel.text = [NSString stringWithFormat:@"%@/%@",[NSString stringWithFormat:@"%d",MAX_NUM],@"0"];

}

}

-(void)textViewDidChange:(UITextView *)textView{

UITextRange *selectedRange = [textView markedTextRange];

//获取高亮部分

UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

//如果是拼音转汉语状态不统计字数，确认输入后统计

if (selectedRange && pos) {

return;

}

[self changeTextNumber:textView];

[self updateSpeechButtonStatus];

}

-(void)textViewDidEndEditing:(UITextView *)textView{

textView.text = [EaseEmoji stringReplaceEmoji:textView.text];

[self changeTextNumber:textView];

[self updateSpeechButtonStatus];

}

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text

{

BOOL isLimit = [CCCommonAPI textViewTextCountLimit:textView range:range text:text maxCount:[NSString stringWithFormat:@"%d",MAX_NUM] isAllowEmoji:YES completeBlock:^{

//执行这里block的时候不执行textViewDidChange，block里面的内容就是textViewDidChange里面的操作

[self changeTextNumber:textView];

[self updateSpeechButtonStatus];

}];

return isLimit;

}

//textview字数限制处理

+ (BOOL)textViewTextCountLimit:(UITextView *)textView range:(NSRange)range text:(NSString *)text maxCount:(NSString *)maxCountStr isAllowEmoji:(BOOL)isAllowEmoji completeBlock:(nonnull CommonTextLimitCompletion)completeBlock{

if (!isAllowEmoji) {

//不允许输入表情的时候返回NO

if ([[[UITextInputMode currentInputMode] primaryLanguage] isEqualToString:@"emoji"]) {

return NO;

}

}

//对于退格删除键开放限制

if (text.length == 0) {return YES;}

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

NSInteger caninputlen = [maxCountStr intValue] - 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]];

completeBlock();

//手动截取更改，不再调用didchange

return NO;

}else{

UITextRange *selectedRange = [textView markedTextRange];

//获取高亮部分

UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

if (selectedRange && pos) {

//如果拼音转汉语状态继续输入

return YES;

}else{

return NO;

}

}

}

}