iOS 7 custom back button

Question

I want to use custom back button. in iOS 6 everything is perfect but iOS 7 is strange.

[[UIBarButtonItem appearance] setBackButtonBackgroundImage:[[UIImage imageNamed:@"back_button_normal"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 12.0, 0, 12.0)] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];

first, it has no iOS 7 arrow and no background image.

(Russian locale)

then, if you press the button background image appears. Also i had background image set for UIControlStateHighlighted state and when you hold the button pressed highlighted image appears too. After any back button once pressed all back buttons have background image.

BUT! If you present modal view controller, dismiss it, then push any view controller - iOS 7 arrow will appear at every back button.

I use DP5. Is that a UIKit bug?

PS Also i tried to create back button manually, using UIBarButtonItem, set background image to it, then self.navigationItem.backBarButtonItem = barButtonItem; Did not help. Then i tried to set background image to disabled state and change enabled property of my bar button item, did not help too.

Solution 1

This is not a bug, this how Back button looks in iOS 7. For example:

You should probably use the new concept for your application, and not to set background image for back button in iOS 7.

If you still want you back button have the same as it looked in iOS6 than you should probably create those back buttons manually:

- (void)loadView
{
    [super loadView];

    UIButton *backButton = [[UIButton alloc] initWithFrame: CGRectMake(0, 0, 60.0f, 30.0f)];
    UIImage *backImage = [[UIImage imageNamed:@"back_button_normal.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 12.0f, 0, 12.0f)];
    [backButton setBackgroundImage:backImage  forState:UIControlStateNormal];
    [backButton setTitle:@"Back" forState:UIControlStateNormal];
    [backButton addTarget:self action:@selector(popBack) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *backButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
    self.navigationItem.leftBarButtonItem = backButtonItem;
}

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

Edit: Not to break Swipe Gesture (Here is a source)

self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;

Solution 2

The custom background image not appearing on the first push was fixed in iOS 7 GM.

To hide standard back indicator use this code:

if ([UINavigationBar instancesRespondToSelector:@selector(setBackIndicatorImage:)]) { // iOS 7
    [navigationBarAppearance setBackIndicatorImage:[UIImage imageNamed:@"transparent_1px"]];
    [navigationBarAppearance setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"transparent_1px"]];
}

Solution 3

The custom background image not appearing initially was not fixed in iOS7 GM or final, as far as I can tell. I see the same problem. It does seem to be an Apple bug; the private view Apple uses simply does not get a setNeedsDisplay call when it needs it on initial display. Doing anything to it which causes that call should fix it -- like pressing on it (which likely changes internal state so it calls setNeedsDisplay on itself), or bringing a modal up (which probably forces a redisplay of the entire view hierarchy on the next viewWillAppear: call).

Using leftBarItems instead also can work, but that may cause a lot of maintenance issues with existing code (some screens may have their own left items, expecting that when set back to nil they restore the original back item, for example).

As mentioned, ideally you would be able to change to a borderless look on iOS7, which means that the bug isn't really apparent (since there is no background image). For some iOS6/iOS7 transition situations though, that may be difficult (lots of screens, and/or the need to support older iOS versions for a while and too hard to have two looks implemented, and it doesn't look good borderless without other changes). If that's the case, the following patch should work:

#import <objc/runtime.h>

@implementation UINavigationBar (BackButtonDisplayFix)

+ (void)load
{
    if ([UIDevice currentDevice].systemVersion.intValue >= 7)
    {
        /*
         * We first try to simply add an override version of didAddSubview: to the class.  If it
         * fails, that means that the class already has its own override implementation of the method
         * (which we are expecting in this case), so use a method-swap version instead.
         */
        Method didAddMethod = class_getInstanceMethod(self, @selector(_displaybugfixsuper_didAddSubview:));
        if (!class_addMethod(self, @selector(didAddSubview:),
                             method_getImplementation(didAddMethod),
                             method_getTypeEncoding(didAddMethod)))
        {
            Method existMethod = class_getInstanceMethod(self, @selector(didAddSubview:));
            Method replacement = class_getInstanceMethod(self, @selector(_displaybugfix_didAddSubview:));
            method_exchangeImplementations(existMethod, replacement);
        }
    }
}

- (void)_displaybugfixsuper_didAddSubview:(UIView *)subview
{
    [super didAddSubview:subview];
    [subview setNeedsDisplay];
}

- (void)_displaybugfix_didAddSubview:(UIView *)subview
{
    [self _displaybugfix_didAddSubview:subview]; // calls the existing method
    [subview setNeedsDisplay];
}

@end

Note: UINavigationBar does currently have an override of the method in question, so I'd expect the method_exchangeImplementations style to be used. I just added the other stuff for safety in case Apple changes their code. We may go borderless ourselves, but I did find this approach worked as an option (until a more thorough UI uplift), at least.

Additional note: This bug appears to be fixed in iOS 7.1. So, the patch could be conditionalized to only install the methods if running >= 7.0 and < 7.1.

Solution 4

There is a better solution that doesn't involve method swizzling.

You need to add UINavigationViewControllerDelegate method somewhere in your app.

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
dispatch_async(dispatch_get_main_queue(), ^{
    [[navigationController.navigationBar subviews] makeObjectsPerformSelector:@selector(setNeedsDisplay)];
});

}

Solution 5

My solution is for iOS 7 and above.

At first, make default back button invisible.

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];

then, set default backIndicatorImage of back button using custom image.

[UINavigationBar appearance].backIndicatorImage = [[UIImage imageNamed:@"topbar_icon_back_n.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
[UINavigationBar appearance].backIndicatorTransitionMaskImage = [[UIImage imageNamed:@"topbar_icon_back_p.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

At this point, make custom UINavigationBar for resizing _UINavigationBarBackIndicatorView which contains above backIndicatorImage.

const CGPoint SANavigationBarOffset = {-8, 11.5};

@implementation SANavigationBar

- (void)layoutSubviews
{
    [super layoutSubviews];

    // set back button position
    NSArray *classNamesToReposition = @[@"_UINavigationBarBackIndicatorView"];

    for (UIView *view in [self subviews]) {
        if ([classNamesToReposition containsObject:NSStringFromClass([view class])]) {
            CGRect frame = [view frame];
            frame.origin.x = 0;
            frame.origin.y = 0;

            [view setFrame:frame];
        }
    }
}

@end

then, set it as my navigationBar

// set custom NavagationBar for back button position
[self.navigationController setValue:[[SANavigationBar alloc] init] forKey:@"navigationBar"];

View more solutions

Comments

[Vinzzz]

iOS 7 is still under NDA... You should look at UINavigationBar new properties introduced with iOS 7, there might be a solution for you there

[rordulu]

see this thread: stackoverflow.com/questions/18099073/…

[user2893370]

I am facing the same issue dude. Did you get any solution for this?

[storoj]

Thanks for reply. Unfortunately it is too expensive to manage back button using leftBarButtonItem in existing project, so we decided to follow the guideline and remove background images for bar buttons in iOS 7. Looks really nice.

[B.S.]

It is nice decision to move forward to the new iOS7 concept

[jAckOdE]

How to hide the back arrow?

[eagle.dan.1349]

Too extensive. You don't need to init itwith custom button. Things can be done easier by customizing appearance of this single BarButtonItem to look like good ol' back button.

[Jin]

Thanks! I use this by subclassing the UINavigationBar and overriding the didAddSubview.

[Lucien]

Thanks a lot! The first two steps are enough to change the default arrow image and hide the back button text.