你不能以你想要的方式访问导航backButtonItem，你需要创建自己的返回按钮，如下所示:

- (void)loadView
{
    [super loadView];
    UIButton *backButton = [[UIButton alloc] initWithFrame: CGRectMake(0, 0, 44.0f, 30.0f)];
    [backButton setImage:[UIImage imageNamed:@"back.png"]  forState:UIControlStateNormal];
    [backButton addTarget:self action:@selector(popVC) forControlEvents:UIControlEventTouchUpInside];
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
}

当然了:

- (void) popVC{
  [self.navigationController popViewControllerAnimated:YES];
}

iOS7有新的界面规则，所以当你推送一个UIView时，最好至少保留后退箭头。 通过编程方式更改“返回”文本非常容易。只需要在推送视图之前添加这段代码(如果你使用的是StoryBoards，可以使用prepareForSegue):

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
      self.navigationItem.backBarButtonItem=[[UIBarButtonItem alloc] initWithTitle:@"NEW TITLE" style:UIBarButtonItemStylePlain target:nil action:nil];
}

这将改变默认的“后退”文本，但将保持iOS7风格的后退箭头。 你也可以在推送视图之前改变后退箭头的颜色:

- (void)viewDidLoad{
     //NavBar background color:
     self.navigationController.navigationBar.barTintColor=[UIColor redColor];
//NavBar tint color for elements:
     self.navigationController.navigationBar.tintColor=[UIColor whiteColor];
}

希望这对你有所帮助!

我从iOS 5开始就一直在使用这个解决方案，没有任何问题。我在视图控制器中调用了一个实用函数。你需要在viewDidLoad或之后的任何点中做。

void updateBackButtonTextForViewController(UIViewController *viewController, NSString *text)
{
    if(! viewController.navigationItem.backBarButtonItem)
    {
        viewController.navigationItem.backBarButtonItem =
        [[UIBarButtonItem alloc] initWithTitle:text
                                         style:UIBarButtonItemStylePlain
                                        target:nil action:nil];
    }
    else
    {
        viewController.navigationItem.backBarButtonItem.title = text;
    }
}

在某些情况下，导航项可能已经存在，在其他情况下需要创建它。这在不影响导航项标题的情况下解释了这两种情况。它允许你通过简单地传入@""来删除标题。

所有的答案都不能解决问题。在每个视图控制器中设置后退按钮标题，并且添加偏移量仍然会使下一个视图控制器标题向右移动，这是不可接受的。

这里是使用方法swizzling的方法，只需创建新的扩展UINavigationItem

import UIKit

extension UINavigationItem {
    public override class func initialize() {

    struct Static {
        static var token: dispatch_once_t = 0
    }

    // make sure this isn't a subclass
    if self !== UINavigationItem.self {
        return
    }

    dispatch_once(&Static.token) {
        let originalSelector = Selector("backBarButtonItem")
        let swizzledSelector = #selector(UINavigationItem.noTitleBackBarButtonItem)

        let originalMethod = class_getInstanceMethod(self, originalSelector)
        let swizzledMethod = class_getInstanceMethod(self, swizzledSelector)

        let didAddMethod = class_addMethod(self, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))

        if didAddMethod {
            class_replaceMethod(self, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod))
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod)
        }
    }
}

// MARK: - Method Swizzling

struct AssociatedKeys {
    static var ArrowBackButtonKey = "noTitleArrowBackButtonKey"
}

func noTitleBackBarButtonItem() -> UIBarButtonItem? {
    if let item = self.noTitleBackBarButtonItem() {
        return item
    }

    if let item = objc_getAssociatedObject(self, &AssociatedKeys.ArrowBackButtonKey) as? UIBarButtonItem {
        return item
    } else {
        let newItem = UIBarButtonItem(title: " ", style: UIBarButtonItemStyle.Plain, target: nil, action: nil)
        objc_setAssociatedObject(self, &AssociatedKeys.ArrowBackButtonKey, newItem as UIBarButtonItem?, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        return newItem
    }
}
}

这在iOS6和ios7上都很有效

Xamarin (c#)选项

var buttonStyleItems = UIBarButtonItem.AppearanceWhenContainedIn(typeof(SettingsNavigationController));
buttonStyleItems.SetBackButtonTitlePositionAdjustment(new UIOffset(-1000, -1000), UIBarMetrics.Default);

objective - c选项

[[UIBarButtonItem外观]setBackButtonTitlePositionAdjustment:UIOffsetMake(-1000， -1000) forBarMetrics:UIBarMetricsDefault];

唯一对我有效的方法是:

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

更新:

当我改变segue动画标志为真(之前是假的)，唯一适合我的方法是:

navigationController?.navigationBar.topItem?.title = ""