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)];
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
}
}
}
目标:
自定义UINavigationBar上的所有后退按钮为白色图标
步骤:
1. 在AppDelete的didFinishLaunchingWithOptions方法中:
UIImage *backBtnIcon = [UIImage imageNamed:@"navBackBtn"];
if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
[UINavigationBar appearance].tintColor = [UIColor whiteColor];
[UINavigationBar appearance].backIndicatorImage = backBtnIcon;
[UINavigationBar appearance].backIndicatorTransitionMaskImage = backBtnIcon;
}else{
UIImage *backButtonImage = [backBtnIcon resizableImageWithCapInsets:UIEdgeInsetsMake(0, backBtnIcon.size.width - 1, 0, 0)];
[[UIBarButtonItem appearance] setBackButtonBackgroundImage:backButtonImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -backButtonImage.size.height*2) forBarMetrics:UIBarMetricsDefault];
}
2.在普通超级ViewController类的viewDidLoad方法中:
if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@""
style:UIBarButtonItemStylePlain
target:nil
action:nil];
[self.navigationItem setBackBarButtonItem:backItem];
}else{
//do nothing
}