Unit 2: MVVM Architecture - Practice Quiz

1 What does MVVM stand for?

2 Which MVVM component stores and manages application data?

3 What is the main role of the ViewModel in MVVM?

4 What is Xcode mainly used for?

5 Which part of the Xcode workspace is primarily used to edit source code?

6 What is Interface Builder used for in Xcode?

7 What can be changed using the Attribute inspector?

8 What is the main purpose of the iOS Simulator?

9 Which Xcode command is commonly used to begin creating a new application project?

10 What is a view controller mainly responsible for?

11 What is an IBOutlet used for?

12 Which keyword commonly appears before an outlet declaration in UIKit?

13 What does an IBAction usually represent?

14 Which user interaction can commonly trigger an action connected to a UIButton?

15 Which UI element is normally used to display a short piece of text?

16 What is Auto Layout used for in an iOS interface?

17 What is a common responsibility of the application delegate?

18 Which navigator is used to browse project files in Xcode?

19 What does the Utility pane commonly contain?

20 In which application state is an iOS app visible and receiving user input?

21 A view controller currently downloads user data, formats it, and updates labels. Under MVVM, where should the formatting logic primarily be moved?

22 A ViewModel exposes an isLoginEnabled property based on whether two text fields contain valid values. What is the main architectural benefit?

23 An iOS project compiles successfully but crashes while running. Which Xcode feature is most appropriate for pausing execution at the suspected line and inspecting variables?

24 While debugging a layout issue, a developer wants more horizontal space for the source editor without closing the project. Which workspace adjustment is most suitable?

25 A label is correctly positioned on one iPhone size but shifts incorrectly on another. What should the developer modify in Interface Builder?

26 A developer needs to change a button's displayed title and text color without writing code. Which Xcode area should be used?

27 A newly created application must be checked on two simulated iPhone screen sizes. What is the most efficient approach?

28 An application needs camera behavior that the selected Simulator runtime cannot reproduce accurately. What should the developer do?

29 A view controller must configure a label after all storyboard outlets have been connected. Which method is the appropriate place for this initial setup?

30 A screen refreshes account data every time it becomes visible after another screen is dismissed. Which view controller method best fits this requirement?

31 An IBOutlet is declared as weak, but the connected label remains visible and usable after loading. What retains the label?

32 A storyboard label was connected to titleLabel, but the property was later deleted from the view controller. What is the likely runtime result if the stale connection remains?

33 Several buttons should call the same IBAction, while the method must identify which button triggered it. Which method signature is most useful?

34 A button's action is connected to the Touch Down event instead of Touch Up Inside. What behavioral difference should be expected?

35 Three buttons should remain equal in width and evenly spaced as the device rotates. Which Interface Builder approach is most appropriate?

36 Which task is most appropriately performed in application(_:didFinishLaunchingWithOptions:)?

37 A build fails because a symbol is undefined, and the developer wants to jump directly through the listed compiler errors. Which navigator should be opened?

38 A source file compiles in the project but is missing from one application target. Which inspector setting should be checked in the utility pane?

39 An application pauses an active timer when it is interrupted by an incoming call. In a traditional app-delegate lifecycle, which callback is most appropriate?

40 A scene-based application should refresh sensitive information whenever its scene returns from the background and becomes interactive. Which callback best matches that moment?

41 A view controller owns a view model, and the view model exposes a closure that the controller assigns to update its UI. Instruments shows that the controller is never deallocated after dismissal. Which change best preserves MVVM communication while fixing the likely leak?

42 A view model fetches data on a background queue and publishes a formatted string that is immediately assigned to a label by the view controller. Which design most correctly handles thread safety and MVVM separation?

43 An Xcode workspace contains an application project and a separate dynamic framework project. Both build independently, but the application reports that the framework module cannot be loaded at runtime. Which configuration is most appropriate?

44 Which mapping of Xcode workspace-window components to responsibilities is correct?

45 A view with width points contains a subview with required leading and trailing constraints of points and a required width constraint of points. The design must preserve both margins on different screen widths. Which Interface Builder change is most appropriate?

46 A developer must set a button's title for its Disabled state, assign an accessibility identifier, and change the storyboard file's target membership. Which inspector sequence should be used?

47 An image named ProfileIcon.png loads in the Simulator, but returns nil on a physical device when requested as profileicon.png. Assuming the asset is copied correctly, what is the most likely cause?

48 In a scene-based iOS project, a developer removes the main storyboard reference from the target settings and creates the window programmatically, but launch still fails while trying to load that storyboard. What was most likely overlooked?

49 A parent view controller programmatically embeds a child controller. Which sequence correctly establishes containment before the child begins normal appearance handling?

50 A XIB contains a helper object as a top-level object. It is connected to a weak outlet but is not inserted into any retained view hierarchy. The outlet becomes nil after loading. What is the best correction?

51 A view model receives data before its view controller's view has loaded. A property observer immediately assigns the data to an implicitly unwrapped label outlet, causing a crash. Which solution best handles this edge case?

52 Four buttons are connected to one IBAction, and their visible titles are localized. The controller must reliably determine which command was requested. Which approach is most robust?

53 A reusable table-view cell calls addTarget(_:action:for:) on its button every time configure runs. After several reuse cycles, one tap invokes the same action multiple times. What is the safest design correction?

54 A multiline label supports Dynamic Type but clips text at accessibility sizes. It has required top and bottom constraints, numberOfLines = 0, and a required fixed-height constraint. Which redesign best preserves accessibility?

55 An interface must switch from a vertical control arrangement in compact width to a horizontal arrangement in regular width, including Split View resizing on iPad. Which design is most reliable?

56 A background URLSession finishes transfers while the application is suspended. iOS relaunches the app and provides a completion handler to the application delegate. When should that handler be called?

57 A test passed locally yesterday but failed in an earlier CI-style Xcode run. The developer needs the complete logs and results from that historical test invocation. Which navigator is most appropriate?

58 A developer selects a storyboard constraint and wants to edit its constant and priority, then selects a Swift file and wants to change its target membership. Which utility-pane inspectors are required in order?

59 A scene-based application is active when the user presses the Home button. Ignoring unusual interruptions, which scene-level callback order should the application expect?

60 An application saves critical user edits only in applicationWillTerminate(_:). Some edits are lost after the system removes the suspended app from memory. Which strategy is correct?