Changing back button in iOS 7 disables swipe to na

Question

I have an iOS 7 app where I am setting a custom back button like this:

    UIImage *backButtonImage = [UIImage imageNamed:@"back-button"];
    UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];

    [backButton setImage:backButtonImage forState:UIControlStateNormal];
    backButton.frame = CGRectMake(0, 0, 20, 20);

    [backButton addTarget:self
                   action:@selector(popViewController)
         forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *backBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
    viewController.navigationItem.leftBarButtonItem = backBarButtonItem;

But this disables the iOS 7 "swipe left to right" gesture to navigate to the previous controller. Does anyone know how I can set a custom button and still keep this gesture enabled?

EDIT: I tried to set the viewController.navigationItem.backBarButtonItem instead, but this doesn't seem to show my custom image.

Answer 1

I also hide the back button, replacing it with a custom leftBarItem.
Removing interactivePopGestureRecognizer delegate after push action worked for me:

[self.navigationController pushViewController:vcToPush animated:YES];

// Enabling iOS 7 screen-edge-pan-gesture for pop action
if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
    self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}

Answer 2

Use the backIndicatorImage and backIndicatorTransitionMaskImage properties of the UINavigationBar if at all possible. Setting these on an a UIAppearanceProxy can easily modify behavior across your application. The wrinkle is that you can only set those on ios 7, but that works out because you can only use the pop gesture on ios 7 anyway. Your normal ios 6 styling can remain intact.

UINavigationBar* appearanceNavigationBar = [UINavigationBar appearance];
//the appearanceProxy returns NO, so ask the class directly
if ([[UINavigationBar class] instancesRespondToSelector:@selector(setBackIndicatorImage:)])
{
    appearanceNavigationBar.backIndicatorImage = [UIImage imageNamed:@"back"];
    appearanceNavigationBar.backIndicatorTransitionMaskImage = [UIImage imageNamed:@"back"];
    //sets back button color
    appearanceNavigationBar.tintColor = [UIColor whiteColor];
}else{
    //do ios 6 customization
}

Trying to manipulate the interactivePopGestureRecognizer's delegate will lead to a lot of issues.