转载：http://www.jianshu.com/p/2d1c06f2dfa4
#define MAX_STARWORDS_LENGTH 30
- (void)textViewDidChange:(UITextView *)textView{
// NSString * nsTextContent=textView.text;
// NSInteger existTextNum=[nsTextContent length];
// NSLog(@"剩余：%ld",30-existTextNum);
NSString *toBeString = textView.text;
NSArray *current = [UITextInputMode activeInputModes];
UITextInputMode *currentInputMode = [current firstObject];
NSString *lang = [currentInputMode 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
//获取高亮部分
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 > MAX_STARWORDS_LENGTH)
{
NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];
if (rangeIndex.length == 1){
textView.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];
}else{
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_STARWORDS_LENGTH)];
textView.text = [toBeString substringWithRange:rangeRange];
}
}
}else{//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
if (toBeString.length > MAX_STARWORDS_LENGTH){
NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];
if (rangeIndex.length == 1){
textView.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];
}else{
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_STARWORDS_LENGTH)];
textView.text = [toBeString substringWithRange:rangeRange];
}
}
}
}