CNContactViewController forUnknownContact unusable

问题:

[Appears to be fixed in iOS 10!] So what follows applies to iOS 9 only...

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I have been experimenting with Apple's new Contacts framework, and I've found a huge bug in one of the three forms of CNContactViewController. It destroys the surrounding interface so that your app becomes useless; the user is stuck.

To make this bug easy to see, I've posted an example project at https://github.com/mattneub/CNContactViewControllerBug.

To experiment, run the project and do the following steps:

1. Tap the button (Unknown Person).

2. Grant access if requested.

3. You are shown the partial contact, in our navigation interface (note the Back button at the top).

4. Tap Add to Existing Contact. The contact picker appears.

5. Tap Cancel. It doesn't actually matter what you do from here, but tapping Cancel is simplest and is the fastest way to reach the bug.

6. We are now back at the partial contact, but the navigation interface is gone. The user has no way to escape from this interface. The app is hosed.

Just to clarify, here are screenshots of the steps you need to take:

Tap Add to Existing Contact to see this:

Tap Cancel to see this; observe that it is the same as the first screen shot, but the navigation bar is gone:

I've tried many ways to work around this bug, but there seems to be no way. As far as I can tell, this window is being presented by the framework "out-of-process" and is not part of your app. You can't get rid of it.

So what's the question? I guess it's this: can anyone show me a way to make this view controller (in this form) usable? Is there a workaround I haven't found?

EDIT This bug appeared in iOS 9.0 and is still present in iOS 9.1. In a comment, @SergeySkopus reports that switching to the deprecated Address Book framework doesn't help; the bug is in the underlying structure somewhere.

回答1:

I've hidden the UINavigationController method for show or hide the navigation bar by using categories:

@interface UINavigationController (contacts)
@end

@implementation UINavigationController (contacts)

- (void)setNavigationBarHidden:(BOOL)hidden animated:(BOOL)animated {
    NSLog(@"Hide: %d", hidden);
}
@end

This way the CNContactViewController cannot make the navigation bar to disappear. Setting a breakpoint on NSLog I discovered that this method is called by the private [CNContactViewController isPresentingFullscreen:].

By checking if the self.topViewController of the navigation controller is kind of class CNContactViewController you could decide if hiding or not the navigation bar.

回答2:

Evidently this is a bug, since Apple has finally responded to my bug report by declaring it a duplicate.

回答3:

The only way I found to make "CNContactViewController forUnknownContact" usable is to abandon the navigationbar and use a toolbar to exit modal view like this (in Objective C):

CNContactViewController *picker = [CNContactViewController viewControllerForUnknownContact: newContact];
picker.delegate = self;

UINavigationController *newNavigationController = [[UINavigationController alloc] initWithRootViewController:picker];

UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleDone target:self action:@selector(YourDismissFunction)];
UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
[picker setToolbarItems:[[NSArray alloc] initWithObjects:flexibleSpace, doneButton, flexibleSpace, nil] animated:NO];

newNavigationController.toolbarHidden = NO;
picker.edgesForExtendedLayout = UIRectEdgeNone;

[self presentViewController:newNavigationController animated:YES completion:nil];

hoping that it could help

回答4:

Are you interested in a very private API fix?

@implementation CNContactViewController (Debug)

+ (void)load
{
    Method m1 = class_getInstanceMethod([CNContactViewController class], NSSelectorFromString(@"".underscore.s.h.o.u.l.d.B.e.O.u.t.O.f.P.r.o.c.e.s.s));
    Method m2 = class_getInstanceMethod([CNContactViewController class], @selector(checkStatus));

    method_exchangeImplementations(m1, m2);
}

- (BOOL)checkStatus
{
    //Leo: Fix bug where in-process contact view controller crashes if there is no access to local contacts.
    BOOL result;
    if([CNContactStore authorizationStatusForEntityType:CNEntityTypeContacts] == CNAuthorizationStatusAuthorized)
    {
        result = NO;
    }
    else {
        result = YES;
    }

    return result;
}

@end

This is a "magic" solution that reverts Apple's use of the buggy XPC controllers. Solves so many issues in both the modern CN controllers, as well as legacy AB controllers, which use the CN ones internally.

回答5:

Well, I found three ways to solve the problem TEMPORARILY.

Swift 2.2 Version:

Option 1: Shake device to show navigation bar or dismiss directly

class CustomContactViewController: CNContactViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        UIApplication.sharedApplication().applicationSupportsShakeToEdit = true
    }

    override func canBecomeFirstResponder() -> Bool {
        return true
    }        

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)            
        becomeFirstResponder()
    }

    override func viewWillDisappear(animated: Bool) {
        super.viewWillDisappear(animated)            
        resignFirstResponder()
        UIApplication.sharedApplication().applicationSupportsShakeToEdit = false
    }

    override func motionEnded(motion: UIEventSubtype, withEvent event: UIEvent?) {
        navigationController?.setNavigationBarHidden(false, animated: true)

        // or just dismiss
        // dismissViewControllerAnimated(true, completion: nil)

        // or pop
        // navigationController?.popViewControllerAnimated(true)

    }
}

Option 2: Set a timer to force the navigation bar to show. But... it also creates a new problem, you cannot edit or share the contact avatar.

class CustomContactViewController: CNContactViewController {

    var timer: NSTimer?

    override func viewDidLoad() {
        super.viewDidLoad()
        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: #selector(showNavigationBar), userInfo: nil, repeats: true)
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        timer?.fire()
    }

    override func viewWillDisappear(animated: Bool) {
        super.viewWillDisappear(animated)
        timer?.invalidate()
    }

    @objc private func showNavigationBar() {
        navigationController?.setNavigationBarHidden(false, animated: true)
    }
}

Option 3: Create a dismiss button on the top most view.

class CustomContactViewController: CNContactViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        configureDismissButton()
    }

    private func configureDismissButton() {

        guard let topView = UIApplication.topMostViewController?.view else { return }

        let button = UIButton()
        button.setImage(UIImage(named: "close"), forState: .Normal)
        button.addTarget(self, action: #selector(dismissViewController), forControlEvents: .TouchUpInside)
        topView.addSubview(button)

        // just use SnapKit to set AutoLayout
        button.snp_makeConstraints { (make) in
            make.width.height.equalTo(36)
            make.bottom.equalTo(8)
            make.left.equalTo(-8)
        }
    }

    @objc private func dismissViewController() {
        dismissViewControllerAnimated(true, completion: nil)
    }

    var topMostViewController: UIViewController? {
        var topController = UIApplication.sharedApplication().keyWindow?.rootViewController
        while topController?.presentedViewController != nil {
            topController = topController?.presentedViewController
        }
        return topController
    }
}

回答6:

This is one of those issues I was glad to see I was not alone.

I have the same issue when displaying a contact using CNContactViewController(contact:).

When the image or 'share contact' was tapped the navigation bar in the root CNContactViewController would disappear making the user stuck. This has not been fixed as of iOS 9.3.3.

The solution for me at this point in time is to use the uitoolbar. The problem is that this appears at the bottom all the time, even with the image data for the contact in full screen.

// initialise new contact view controller to display with contact
                let contactVC = CNContactViewController(forContact: contact!)

                // set view controller delegate
                contactVC.delegate = self

                // set view controller contact store
                contactVC.contactStore = self.store

                // enable actions
                contactVC.allowsActions = true

                // disable editing
                contactVC.allowsEditing = false

                // add cancel button
                let cancelButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Cancel, target: self, action: #selector(dismissContactVC(_:)))

                // add flexible space
                let flexibleSpace = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.FlexibleSpace, target: nil, action: nil)

                // add to toolbar
                contactVC.setToolbarItems([flexibleSpace, cancelButton, flexibleSpace], animated: false)

                // contact view controller must be embedded in navigation controller
                // initialise navigation controller with contact view controller as root
                let navigationVC = SubClassNavigationController(rootViewController: contactVC)

                // show toolbar
                navigationVC.setToolbarHidden(false, animated: false)

                // set navigation presentation style
                navigationVC.modalPresentationStyle = UIModalPresentationStyle.CurrentContext

                // present view controller
                self.presentViewController(navigationVC, animated: true, completion: nil)

After this a blank navigation bar appears when you first present the cncontactviewcontroller so to remove this I subclassed uinavigationcontroller, and in viewWillAppear(animated:) I call the function setnavigationbar(hidden: animated:) to hide the navigation bar.

I hope Apple fixes this soon as this is a less than ideal solution.

回答7:

This problem can easily solved. Subclass CNContactViewController and in the viewDidAppear method first call the super class and then immediately following set the leftBarButtonItem with an action method that calls dismissViewController. Also make sure that you embed that viewController into a navigation controller.