UIViewController Lifecycle

MediumPython

Problem

Describe the lifecycle of a UIViewController and tell me which event is called before a UIViewController is displayed on screen.

Implement a validator for an observed callback sequence. Return whether the sequence follows the expected UIKit order and identify viewWillAppear as the pre-display event when it occurs.

Use analyze_view_controller_lifecycle(events), where events is a list of callback names and the result is a dictionary containing valid and before_display.

Constraints

1 <= events.length <= 100
Each event is one of: loadView, viewDidLoad, viewWillAppear, viewWillLayoutSubviews, viewDidLayoutSubviews, viewDidAppear, viewWillDisappear, viewDidDisappear
loadView and viewDidLoad may occur at most once and must appear together
A valid appearance must include all four appearance and layout callbacks in order

Function Signature

def analyze_view_controller_lifecycle(events):

Code

Run your code to see test output here.