Adding left button to UINavigationBar (iPhone)
问题 I've created a new navigation based iPhone app. I added this to the RootViewController. - (void)viewDidLoad { [super viewDidLoad]; UIBarButtonItem *addButton = [[UIBarButtonItem alloc] init]; self.navigationItem.leftBarButtonItem = addButton; self.navigationItem.leftBarButtonItem.enabled = YES; } No left button displays however. Is there something I need to do? 回答1: You don't define what the button actually does. This is a line from my app: self.navigationItem.leftBarButtonItem = [