以下是答案:

在viewDidAppear:animated中(不是在viewDidLoad中)执行以下操作

- (void)viewDidAppear:(BOOL)animated
{
     [self.navigationController.navigationBar.backItem setTitle:@"anything"];

     // then call the super
     [super viewDidAppear:animated];
}

如果你想保持后退按钮的形状。

self.navigationController.navigationBar.backItem.title = @"TEXT";

在Swift中:

self.navigationController?.navigationBar.backItem?.title = "TEXT"

我们有两个VC A和B。

如果你想在B中更改标题，请在A中编写这段代码

- (IBAction)goToBViewController:(UIButton *)sender {

    BViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"VC"];
    UIBarButtonItem *newBackButton = [[UIBarButtonItem alloc] initWithTitle:@"Your title here"
                                                                  style:UIBarButtonItemStylePlain
                                                                 target:nil
                                                                 action:nil];
    [[self navigationItem] setBackBarButtonItem:newBackButton];
    [self.navigationController pushViewController:vc animated:NO];

}

Swift 4.1 Xcode 9.4

let secondViewController = self.storyboard?.instantiateViewController(withIdentifier: "VC"])
let newBackButton = UIBarButtonItem.init(title: "Your title here", style: UIBarButtonItemStyle.plain, target: nil, action: nil)
navigationController?.navigationBar.topItem?.backBarButtonItem = newBackButton
navigationController?.pushViewController(secondViewController!, animated: true)

self.navigationItem.backBarButtonItem = [[[UIBarButtonItem alloc] 
                                              initWithTitle:@"Log out" 
                                              style:UIBarButtonItemStyleDone 
                                              target:nil 
                                              action:nil] autorelease];

你可以把它放在父控制器代码中的任何你喜欢的地方，这允许你为不同的子视图有不同的后退按钮。

这在Swift 4和iOS 11中都适用。最常见的情况是，当用户点击表视图中的一行，一个新的视图控制器被推送到导航堆栈时，我需要这样做。通常我希望返回按钮是被点击的行所表示的对象的名称或某些属性。我通常在didSelectRowAt中这样做。是这样的:

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

    let object = // get the object this row represents

    let backButton = UIBarButtonItem()
    backButton.title = object.name // or whatever
    self.navigationItem.backBarButtonItem = backButton

    // now show or segue to the next view controller
}

这段代码也可以工作。把这个放到导航控制器的根控制器上:

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];