Adding left button to UINavigationBar (iPhone)

Question

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?

Answer 1

You don't define what the button actually does. This is a line from my app:

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelEdit:)]; 

cancelEdit:, the selector, is in the current class (self) and is defined as:

- (void) cancelEdit: (id) sender; 

Answer 2

There is actually another answer, which is not listed here, but might be very useful in many cases. If you do not want to use UINavigationController, then self.navigationItem is not an option for you.

UIBarButtonItem *barButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"imageName"] style:UIBarButtonItemStyleBordered target:self action:@selector(action:)]; UINavigationItem *navigationItem = [[UINavigationItem alloc] initWithTitle:@"Bar Title"]; navigationItem.leftBarButtonItem = barButton; [navigationBar pushNavigationItem:navigationItem animated:NO]; 

You might want that when creating lightweight UIViewController with bar and buttons, but do not want navigation overhead.