UISplitViewController detecting Back Button pressed

Question

I have a UISplitViewController where I want to always display the master and detail view controllers for iPads. This line takes care of that for me:

// Always display master and detail in large screens
self.preferredDisplayMode = UISplitViewControllerDisplayMode.AllVisible

In the prepareForSegue, when opening up the detail view controllers, I have the following lines of code for the Back Button

controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
controller.navigationItem.leftItemsSupplementBackButton = true

Now when the user pressed that back button, I will want to perform an action after the Master view controller is hidden. I am not having any luck finding how to do that. In the SplitViewControllerDelegate I attempted to use:

func splitViewController(svc: UISplitViewController, willChangeToDisplayMode displayMode: UISplitViewControllerDisplayMode)

But that function is called before the Detail view controller becomes full screen. Is there a function or something else I can do to help notify me when the UISplitViewController finishes hiding the Master View?

What about putting it in `viewDidDisappear` for the master view controller? — aganders3, Apr 07 '15 at 16:31
I put println statements in viewDidDisappear, viewWillDisappear, viewWillAppear and they aren't called when I show and hide the master view controller. — Mike Walker, Apr 07 '15 at 17:43

score 0 · Answer 1 · answered May 22 '15 at 14:53

You can add an observer on the view's with in the DetailViewController, and perform your specific action when it triggers:

- (void)viewDidLoad {
  [super viewDidLoad];

  [self addObserver:self forKeyPath:@"view.frame" options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionInitial context:nil];
}

- (void)viewWillDisappear:(BOOL)animated {
  [super viewWillDisappear:animated];
  if ([self observationInfo]) {
    @try {
      [self removeObserver:self forKeyPath:@"view.frame"];
    }
    @catch (NSException *exception) {}

  }
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
  if (object == self && [keyPath isEqualToString:@"view.frame"]) {
    // do your action here
  }
}

score 0 · Answer 2 · answered Apr 03 '18 at 07:53

0

You can try the delegate method

- (UISplitViewControllerDisplayMode)targetDisplayModeForActionInSplitViewController:(UISplitViewController *)svc;

answered Apr 03 '18 at 07:53

daris mathew

429
5
18

score 0 · Answer 3 · answered Mar 25 '23 at 04:45

I got the answer from here. You need to put it in the MasterController (the one on the left side).

FYI this inactivated the expand button and to get it to expand/retract I put the extra code inside doSomethingWhenExpandButtonTapped()

navigationController?.topViewController?.navigationItem.leftBarButtonItem?.action = #selector(doSomethingWhenExpandButtonTapped)
navigationController?.topViewController?.navigationItem.leftBarButtonItem?.target = self

@objc func doSomethingWhenExpandButtonTapped() {
    print("splitViewController's expand and back button pressed")

    if splitViewController?.preferredDisplayMode == .allVisible {
        splitViewController?.preferredDisplayMode = .primaryHidden
    } else {
        splitViewController?.preferredDisplayMode = .allVisible
    }
}

UISplitViewController detecting Back Button pressed

3 Answers3