UITextView 限制字符長度

頁面啟動時添加通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textViewChange:) name:@"UITextViewTextDidChangeNotification" object:self.txtSuggestion];


(BOOL)textView:(UITextView )textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString )text
{
  NSString *toBeString = [textView.text stringByReplacingCharactersInRange:range withString:text];
  if (toBeString.length > kMaxLength && range.length!=1){
  textView.text = [toBeString substringToIndex:kMaxLength];
  return NO;

  }
  return YES;
}

-(void)textViewChange:(NSNotification )obj{
    UITextField textField = (UITextField *)obj.object;

NSString *toBeString = textField.text;
NSString *lang = [[UIApplication sharedApplication]textInputMode].primaryLanguage; // 鍵盤輸入模式
if ([lang isEqualToString:@"zh-Hans"]) { // 簡體中文輸入，包括簡體拼音，健體五筆，簡體手寫
    UITextRange *selectedRange = [textField markedTextRange];
    //獲取高亮部分
    UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
    // 沒有高亮選擇的字，則對已輸入的文字進行字數統計和限制
    if (!position) {
        if (toBeString.length > kMaxLength) {
            textField.text = [toBeString substringToIndex:kMaxLength];
        }
    }
    // 有高亮選擇的字符串，則暫不對文字進行統計和限制
    else{

    }
}
// 中文輸入法以外的直接對其統計限制即可，不考慮其他語種情況
else{
    if (toBeString.length > kMaxLength) {
        textField.text = [toBeString substringToIndex:kMaxLength];
    }  
}  

}
離開頁面時
[[NSNotificationCenter defaultCenter]removeObserver:self name:@"UITextFieldTextDidChangeNotification"

object:self.txtSuggestion];</pre>