leftBarButtonItem位置不正确

Question

我正在尝试在导航栏中添加自定义按钮，但导航栏中的位置偏离左侧。这是我正在看的（注意“菜单”按钮太远了）：

以下是我将按钮添加到当前viewcontroller的方法。在ViewDidLoad中调用setupMenu。

 -(void)setupMenu{
    self.navigationItem.leftBarButtonItem = [self leftMenuBarButtonItem];
}

- (UIBarButtonItem *)leftMenuBarButtonItem {
    UIBarButtonItem *menuButton = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"GuidanceNavMenu", nil) style:UIBarButtonItemStylePlain target:self action:@selector(popToOpenMenu)];

    NSMutableParagraphStyle *paragraphStyle = NSMutableParagraphStyle.new;

    [menuButton setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                        [UIFont openSansFontOfSize:14.0f], NSFontAttributeName,
                                        [UIColor blackColor], NSForegroundColorAttributeName,
                                        nil]
                              forState:UIControlStateNormal];

    return menuButton;
}