Setting a Custom Image for a Back Button on UINavi

问题:

I am trying to set a custom image for the back button that automatically gets place onto a navigation bar when a new view is pushed onto the stack.

I have tried adding the following in the viewDidLoad of the parent viewController:

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

I have also tried the following:

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

Using UIAppearance produces quite strange results:

回答1:

try this code

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;

then define goback method like this

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

回答2:

Since iOS 7.0 there is a new method in API backIndicatorImage. You can use it instead of setBackButtonBackgroundImage if you don't want the image to be stretched to fit the text (for example if you want a fixed size custom back arrow). Here's an example in swift:

let image = UIImage(named: "back_button")

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

You can hide the text from the button using this trick:

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

回答3:

This is the code I'm using and works perfectly in my own iOS 5 app. This code is from application:didFinishLaunchingWithOptions: in the app delegate:

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

You'll may need to use a stretchable image, where the left facing "point" is the left cap

---

or in Swift

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

回答4:

iOS 8+ Swift version (can be converted to ObjC with not much effort). This method preserves all advantages and behaviour of navigation bar related to standard back button (animation on pushing/popping, interactive pop gesture, etc)

// 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)

回答5:

Try the code below, it works for me:

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

回答6:

This code worked for Swift 5 and XCode 10 :

Add this code to AppDelegate's func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool to Apply to all of your view controllers:

//Custom back button
    let barButtonItemAppearance = UIBarButtonItem.appearance()
    barButtonItemAppearance.setTitleTextAttributes([NSAttributedStringKey.foregroundColor: UIColor.clear], for: .normal)
    barButtonItemAppearance.setTitleTextAttributes([NSAttributedStringKey.foregroundColor: UIColor.clear], for: .highlighted)
    let backImg: UIImage = UIImage(named: "back")!
    barButtonItemAppearance.setBackButtonBackgroundImage(backImg, for: .normal, barMetrics: .default)

    let image = UIImage()

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

回答7:

Write this method in common class and call it from the controller in which you want to draw.

(UIButton *)drawNavigationBarBackButton:(UIViewController*)viewController 
{

    UIImage *navBackImage = nil;

    UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
     navBackImage = [UIImage imageNamed:@"Back_Button"];

    [backButton setImage:navBackImage forState:UIControlStateNormal];
    UIBarButtonItem *leftButton = [[UIBarButtonItem alloc] initWithCustomView:backButton];
    viewController.navigationItem.leftBarButtonItem = leftButton;

    return backButton;
}



call from controller class and setting action

- (void)viewDidLoad {

[super viewDidLoad];

 UIButton *backButton = [CommonClass drawNavigationBarBackButton:self];
    [backButton addTarget:self action:@selector(onTapBackButton) forControlEvents:UIControlEventTouchUpInside];
}

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

回答8:

This worked for me:

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