editButtonItem doesn't change Edit/Done title

I use a default Bar Button Item editButtonItem here:

@property (nonatomic, assign) BOOL isEditing;

- (void)viewDidLoad {
  [super viewDidLoad];
self.navigationItem.rightBarButtonItem = self.editButtonItem;
[self setupInterface];
}

- (void)setupInterface {
    if (self.dataElement) {
        self.isEditing = NO;
        self.nameTextField.text = self.dataElement.name;;
    } else {
      self.isEditing = YES;
      self.deleteButton.hidden = YES;
    }
  }

- (void)setEditing:(BOOL)editing animated:(BOOL)animated {
  editing = self.isEditing;
  [super setEditing:editing animated:YES];
  if (editing) {
    [self saveAction];
    [self.navigationController popViewControllerAnimated:YES];
  } else {
    self.isEditing = !self.isEditing;
  }
}

- (void)setIsEditing:(BOOL)isEditing {
  _isEditing = isEditing;

    if (isEditing) {
      self.deleteButton.hidden = NO;
      self.nameTextField.userInteractionEnabled = YES;
    } else {
      self.deleteButton.hidden = YES;
      self.nameTextField.userInteractionEnabled = NO;
    }
}

However it doesn't change title of a button from Edit to Done. I know, that it can be changed automatically and don't want to assign it like: self.editButtonItem.title = @"Done";

Found a solution: We have to use only - (void)setEditing:(BOOL)editing animated:(BOOL)animated method.

It could be useful for someone:

- (void)viewDidLoad {
  [super viewDidLoad];
self.navigationItem.rightBarButtonItem = self.editButtonItem;
[self setupInterface];
}

- (void)setupInterface {

    if (self.dataElement) {
        self.nameTextField.text = self.dataElement.name;
    }
}

- (void)setEditing:(BOOL)editing animated:(BOOL)animated {
  [super setEditing:editing animated:YES];

    if (editing) {
        self.deleteButton.hidden = (self.dataElement == nil);
        self.addImageButton.hidden = NO;
        self.nameTextField.userInteractionEnabled = YES;

    } else {
        self.deleteButton.hidden = YES;
        self.addImageButton.hidden = YES;
        self.nameTextField.userInteractionEnabled = NO;

        [self saveAction];
    }
}

For now everything works right.