textView输入中文时和高亮英文输入法时的字数统计

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textViewEditChanged:) name:@"UITextViewTextDidChangeNotification" object:_textView];

- (void)textViewEditChanged:(NSNotification *)obj{
    
    UITextView *textField = (UITextView *)obj.object;
    
    NSLog(@"========%@",textField.text);
    
    NSString *toBeString = textField.text;
    NSString *lang = [[UITextInputMode 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
        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 > 10) {
                textField.text = [toBeString substringToIndex:10];
                
                [[[UIAlertView alloc] initWithTitle:@"dsfsa" message:@"msg" delegate:self cancelButtonTitle:nil otherButtonTitles:@"SURE", nil] show];
                
                [self.textView resignFirstResponder];
            }
        }
        // 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 > 10) {
            textField.text = [toBeString substringToIndex:10];
            
            [[[UIAlertView alloc] initWithTitle:@"dsfsa" message:@"msg" delegate:self cancelButtonTitle:nil otherButtonTitles:@"SURE", nil] show];
        }
    }
    
}

- (void)dealloc{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"UITextViewTextDidChangeNotification" object:_textView];
}