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

我写了一个扩展,使这更容易:

extension UIViewController {

    /// Convenience for setting the back button, which will be used on any view controller that this one pushes onto the stack
    @objc var backButtonTitle: String? {
        get {
            return navigationItem.backBarButtonItem?.title
        }
        set {
            if let existingBackBarButtonItem = navigationItem.backBarButtonItem {
                existingBackBarButtonItem.title = newValue
            }
            else {
                let newNavigationItem = UIBarButtonItem(title: newValue, style:.plain, target: nil, action: nil)
                navigationItem.backBarButtonItem = newNavigationItem
            }
        }
    }

}

其他回答

添加新的UIBarButtonItem到左边的UINavigationItem 改变UIBarButtonItem的使用方式 现在,点击UINavigationItem,并从outlets滑动barBackButtonItem到左UIBarButtonItem

虽然Kyle Begeman的回答完全做到了,但在每个视图控制器中都使用这种代码是相当烦人的。我最终得到了一个简单的UINavigationItem类别。小心,这里有龙!抱歉,我的意思是:

#import <objc/runtime.h>

@implementation UINavigationItem (ArrowBackButton)

static char kArrowBackButtonKey;

+ (void)load {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Method m1 = class_getInstanceMethod(self, @selector(backBarButtonItem));
        Method m2 = class_getInstanceMethod(self, @selector(arrowBackButton_backBarButtonItem));
        method_exchangeImplementations(m1, m2);
    });
}

- (UIBarButtonItem *)arrowBackButton_backBarButtonItem {
    UIBarButtonItem *item = [self arrowBackButton_backBarButtonItem];
    if (item) {
        return item;
    }

    item = objc_getAssociatedObject(self, &kArrowBackButtonKey);
    if (!item) {
        item = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStyleBordered target:nil action:NULL];
        objc_setAssociatedObject(self, &kArrowBackButtonKey, item, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
    return item;
}

@end

编辑:2014-04-09:当我获得声誉时,我感到抱歉,因为我不再使用这个技巧了。我推荐凯尔的答案。还要注意self。navigationitem。backbarbuttonitem的self不是返回按钮显示的视图控制器,而是要返回的前一个视图控制器。

如果之前的视图控制器不需要标题文本,只需用空白字符串填充标题;

self.navigationItem.title = @"";
[self.navigationController pushViewController:viewController animated:YES];

这将防止在被推送的视图控制器上显示带雪佛龙的“返回”。

编辑:即使你使用非空白标题文本,在viewWillAppear中设置前一个视图控制器的标题:除了标题可以闪烁在闪烁时,视图控制器弹出。我认为“推特应用程序”似乎做了更微妙的hack来避免闪烁。

我在viewDidLoad中应用了以下代码,它可以工作:

  // this will set the back button title
self.navigationController.navigationBar.topItem.title = @"Test";

 // this line set the back button and default icon color  

//[[self.navigationController.navigationBar.subviews lastObject] setTintColor:[UIColor blackColor]];

this line change the back default icon to your custom icon
[[self.navigationController.navigationBar.subviews lastObject] setTintColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"menuicon"]]];

只是更新我使用矢量图标

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