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

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
    }
}
}

其他回答

你可以用这个。这对我来说是完美的,只是添加一个UIButton作为UIBarButtonItem的定制视图。

试试下面的代码

    self.navigationItem.leftBarButtonItem=[self backButton];


- (UIBarButtonItem *)backButton
{
    UIImage *image = [UIImage imageNamed:@"back-btn.png"];
    CGRect buttonFrame = CGRectMake(0, 0, image.size.width, image.size.height);

    UIButton *button = [[UIButton alloc] initWithFrame:buttonFrame];
    [button addTarget:self action:@selector(backButtonPressed) forControlEvents:UIControlEventTouchUpInside];
    [button setImage:image forState:UIControlStateNormal];

    UIBarButtonItem *item= [[UIBarButtonItem alloc] initWithCustomView:button];

    return item;
}

iOS6的简单破解也适用于iOS7:

[UIBarButtonItem.appearance setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault];

编辑: 不要使用这种方法。详情见评论。

你可以把这个类别放在AppDelegate中。m文件。 移除UINavigation中所有默认后退按钮的文本。只有箭头“<”或设置自定义图像,如果你需要。

objective - c:

...

@end

@implementation UINavigationItem (Extension)

- (UIBarButtonItem *)backBarButtonItem {

    return [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
}

@end

为你的根视图控制器创建一个带有标题的UILabel,并将它分配给视图控制器的navigationItem.titleView。

现在将标题设置为空字符串,你按下一个视图控制器将有一个没有文本的返回按钮。

self.navigationItem.titleView = titleLabel; //Assuming you've created titleLabel above
self.title = @"";

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
            }
        }
    }

}