iOS - Log UI events like a view controller appears/disappears

Question

BugFender has a feature called UI Logging . What it does, for example, is monitors when a view controller comes onscreen and logs the information. Another example is when a button is touched:

Fri Aug 25 2017 08:24:30 GMT+0200 (CEST) UI Front-most view controller: SettingsViewController (title: "Settings")
Fri Aug 25 2017 08:24:35 GMT+0200 (CEST) Interaction Action [UIBarButtonItem _sendAction:withEvent:] by sender UINavigationButton (title:"Log Out")
Fri Aug 25 2017 08:24:35 GMT+0200 (CEST) Interaction Action [SettingsViewController logOut:] by sender UIBarButtonItem (title:"Log Out")
Fri Aug 25 2017 08:24:36 GMT+0200 (CEST) UI Front-most view controller: UIAlertController

I would like to implement have the same functionality.

How do I observe all view controllers in my app for appearance/disappearance?

So far, I have found out, I could observe UINavigationControllerDidShowViewControllerNotification notifications. However, this won't log changes in UITabBarViewController, or when a view controller is presented modally without being wrapped in a UINavigationController.

Answer 1

One of the ways is to add a base class (let's say BaseViewController) and override the base class's viewWillAppear and viewWillDisappear methods to observe the changes. All your other viewControllers would be subclasses of this BaseViewController.