UINavigationControllerサブクラスがあり、viewDidLoadに次のコードがあります。
self.containerView_ = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, self.navigationController.navigationBar.frameHeight)];
[self.containerView_ setBackgroundColor:[UIColor yellowColor]];
[self.containerView_ setAutoresizingMask:UIViewAutoresizingNone];
self.profileButton_ = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
[self.profileButton_ addTarget:self action:@selector(showProfileView:) forControlEvents:UIControlEventTouchUpInside];
[self.profileButton_ setCenterY:self.navigationController.navigationBar.frameHeight/2];
[self.profileButton_ setImage:[UIImage imageNamed:@"profile_icon.png"] forState:UIControlStateNormal];
self.socialButton_ = [[UIButton alloc] initWithFrame:CGRectMake(self.profileButton_.frameRight + 10, 0, 30, 30)];
[self.socialButton_ addTarget:self action:@selector(showSocialView:) forControlEvents:UIControlEventTouchUpInside];
[self.socialButton_ setCenterY:self.profileButton_.centerY];
[self.socialButton_ setImage:[UIImage imageNamed:@"social_icon.png"] forState:UIControlStateNormal];
self.notesButton_ = [[UIButton alloc] initWithFrame:CGRectMake(self.socialButton_.frameRight + 10, 0, 30, 30)];
[self.notesButton_ addTarget:self action:@selector(showNotesView:) forControlEvents:UIControlEventTouchUpInside];
[self.notesButton_ setCenterY:self.profileButton_.centerY];
[self.notesButton_ setImage:[UIImage imageNamed:@"notes_icon.png"] forState:UIControlStateNormal];
[self.containerView_ addSubview:self.profileButton_];
[self.containerView_ addSubview:self.notesButton_];
[self.containerView_ addSubview:self.socialButton_];
[self.navigationBar addSubview:self.containerView_];
UIButtonは表示されますが、コンテナの背景は黄色でもありません。ボタンを押しても、UIButtonのアクションは呼び出されません。これがなぜなのか、何か考えはありますか?