在UINavigationBar上为后退按钮设置自定义图像

Question

我正在尝试为后退按钮设置自定义图像，当新视图被压入堆栈时，该按钮会自动进入导航栏。

我尝试在父viewController的viewDidLoad中添加以下内容：

[[UIBarButtonItem appearance] setBackButtonBackgroundImage:[UIImage imageNamed:@"BackButton.png"] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];

我也尝试过以下方法：

UIBarButtonItem *btn = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"BackButton.png"] style:UIBarButtonItemStyleBordered target:nil action:nil];
    self.navigationItem.backBarButtonItem = btn;

使用UIAppearance会产生非常奇怪的结果：

Answer 1

试试这段代码

UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom];  
UIImage *backBtnImage = [UIImage imageNamed:@"BackBtn.png"]  ;  
[backBtn setBackgroundImage:backBtnImage forState:UIControlStateNormal];  
[backBtn addTarget:self action:@selector(goback) forControlEvents:UIControlEventTouchUpInside];  
backBtn.frame = CGRectMake(0, 0, 54, 30);  
UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithCustomView:backBtn] ;  
self.navigationItem.leftBarButtonItem = backButton;

然后像这样定义goback方法

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

Answer 2

从iOS 7.0开始，API backIndicatorImage中有一种新方法。如果您不希望图像被拉伸以适合文本（例如，如果您想要固定大小的自定义后退箭头），则可以使用它而不是setBackButtonBackgroundImage。这是swift中的一个例子：

let image = UIImage(named: "back_button")

UINavigationBar.appearance().backIndicatorImage = image
UINavigationBar.appearance().backIndicatorTransitionMaskImage = image

您可以使用此技巧隐藏按钮中的文本：

UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffsetMake(0, -66), for: .default)

Answer 3

这是我正在使用的代码，并且在我自己的iOS 5应用程序中完美运行。此代码来自app delegate中的application:didFinishLaunchingWithOptions:：

UIImage * backButtonImage = [UIImage imageNamed: @"back-button-image"];
backButtonImage = [backButtonImage stretchableImageWithLeftCapWidth: 15.0 topCapHeight: 30.0];
[[UIBarButtonItem appearance] setBackButtonBackgroundImage: backButtonImage forState: UIControlStateNormal barMetrics: UIBarMetricsDefault];

您可能需要使用可伸缩的图像，其中左侧面向“点”的是左侧盖帽

---

或者在斯威夫特

let backButtonImage = UIImage(named: "back-button-image")
backButtonImage = backButtonImage?.stretchableImageWithLeftCapWidth(15, topCapHeight: 30)
UIBarButtonItem.appearance().setBackButtonBackgroundImage(backButtonImage, forState: .Normal, barMetrics: .Default)

Answer 4

iOS 8+ Swift版本（可以毫不费力地转换为ObjC）。此方法保留了与标准后退按钮相关的导航栏的所有优点和行为（推/弹出动画，交互式弹出手势等）

// Call the code ONE TIME somewhere on app launch to setup custom back button appearance
UINavigationBar.appearance().tintColor = UIColor.blackColor()
// If you need custom positioning for your back button, in this example button will be 1 px up compared to default one
// Also only vertical positioning works, for horizontal add offsets directly to the image
let backImageInsets = UIEdgeInsetsMake(0, 0, -1, 0)
// Get image, change of rendering (so it preserves offsets made in file), applying offsets
let backImage = UIImage(named: "YourButtonImageAssetFileName")?.imageWithRenderingMode(.AlwaysOriginal).imageWithAlignmentRectInsets(backImageInsets)
// Setting images
UINavigationBar.appearance().backIndicatorImage = backImage
UINavigationBar.appearance().backIndicatorTransitionMaskImage = backImage

// Call EACH TIME BEFORE pushing view controller if you don't need title near your back button arrow
self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .Plain, target: nil, action: nil)
// Push controller
self.navigationController?.pushViewController(vc, animated: true)

Answer 5

试试下面的代码，它对我有用：

[[UINavigationBar appearance] setBackIndicatorImage:[UIImage imageNamed:@"back-button-image"]];
[[UINavigationBar appearance] setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"back-button-image"]];

Answer 6

这对我有用：

let button1 = UIBarButtonItem(
    image: #imageLiteral(resourceName: "back_arrow"), 
    style: .plain, 
    target: self, 
    action: #selector(self.backBtnTapped(_:))
)
self.navigationItem.leftBarButtonItem  = button1

Answer 7

此代码适用于Swift 4和XCode 9.4：

将此代码添加到AppDelegate qazxsw poi以应用于所有视图控制器：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool