iOS textfield输入长度限制汉字无效

-(void)textFiledEditChanged:(NSNotification *)obj{

UITextField *textField = (UITextField *)obj.object;

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 > 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];

}

}

}

-(void)dealloc{

[[NSNotificationCenter
defaultCenter]removeObserver:self

name:@"UITextFieldTextDidChangeNotification"

object:_albumNameTextField];

}