我如何自定义导航返回按钮在iOS 7及以上没有标题?(即只使用箭头)

self.navigationItem.leftBarButtonItem = self.editButtonItem;

我只是想知道它们是否有self。backbuttonitem;

OR

像这样的东西?

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

当前回答

改变backItem。title = "" to使用topItem。标题= "" 设置navigationItem。hidesBackButton = true & navigationItem。leftBarButtonItem将失去后退手势 记住,我们必须创建2个back映像的实例

我的解决方案将改变图像和保持后面的手势:

navigationController?.navigationBar.backIndicatorImage = UIImage(named: "back")
navigationController?.navigationBar.backIndicatorTransitionMaskImage = UIImage(named: "back")
navigationController?.navigationBar.topItem?.title = ""

其他回答

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。

你可以在viewWillDisappear上将当前ViewController的标题改为@"",当它即将再次显示时,将标题重新设置为之前的标题。

-(void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    self.title = @"Previous Title";
}

-(void) viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    self.title = @"";
}

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
    }
}
}

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];
}

你可以子类化UINavigationController,将自己设置为委托,并在委托方法navigationController:willShowViewController:animated中设置backBarButtonItem:

@interface Custom_NavigationController : UINavigationController <UINavigationControllerDelegate>

@end

@implementation Custom_NavigationController

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.delegate = self;
}

#pragma mark - UINavigationControllerDelegate

- (void)navigationController:(UINavigationController *)navigationController     willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    viewController.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
}

@end