如何以编程方式设置导航栏的标题？

self.navigationItem.title = @\"The title\";

navigationBar.topItem?.title = \"Your Title\"

  self.title = @\"Title\";

self.navigationItem.title = @\"title\";

UINavigationBar* navbar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 64)];

/* Create navigation item object & set the title of navigation bar. */
UINavigationItem* navItem = [[UINavigationItem alloc] initWithTitle:self.shoppingItem.name];

/* Create left button item. */
UIBarButtonItem* cancelBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(onTapCancel:)];
navItem.leftBarButtonItem = cancelBtn;

/* Create left button item. */
UIBarButtonItem* doneBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(onTapDone:)];
navItem.rightBarButtonItem = doneBtn;

/* Assign the navigation item to the navigation bar.*/
[navbar setItems:@[navItem]];

/* add navigation bar to the root view.*/
[self.view addSubview:navbar];

initWithNibName:

  self.navigationItem.title = @\"title\";