Unit 6: Web Services - Practice Quiz

1 Which framework is primarily used to display interactive maps in an iPhone application?

2 Which MapKit class displays a map in an iOS user interface?

3 Which protocol is commonly implemented to respond to events from an MKMapView?

4 Which MKMapView property is enabled to display the user's current location?

5 Which structure represents a geographic coordinate using latitude and longitude?

6 Which MapKit type describes the visible region of a map using a center and a span?

7 Which method changes the visible region of an MKMapView?

8 Which delegate method is called after the visible map region changes?

9 What is an annotation commonly used for in MapKit?

10 Which method adds a single annotation to an MKMapView?

11 Which framework provides the WKWebView class?

12 What is the main purpose of WKWebView in an iOS application?

13 Which object is commonly passed to WKWebView.load(_:) to load a web address?

14 Which method loads an HTML string directly into a WKWebView?

15 Which protocol receives navigation events from a WKWebView?

16 Which WKWebView property is set to monitor web navigation events?

17 Which method reloads the current page in a WKWebView?

18 Which method navigates a WKWebView to the previous page in its history?

19 Which property indicates whether a WKWebView can navigate to a previous page?

20 Which WKWebView property indicates whether web content is currently loading?

21 An app must detect when the user finishes panning or zooming an MKMapView. Which delegate method should it implement?

22 A map should initially display a coordinate with a specified latitude and longitude span. Which value should be passed to setRegion(_:animated:)?

23 An app sets mapView.showsUserLocation = true, but the user's location does not appear. What is the most likely missing requirement?

24 A developer wants to display a pin for a restaurant without creating a custom annotation class. Which object is most appropriate?

25 A route is added to a map using mapView.addOverlay(route.polyline), but no line is visible. Which implementation is also required?

26 Which approach efficiently reuses annotation views when many annotations are displayed?

27 An app should continuously keep the map centered on the user's movement. Which MapKit feature best matches this requirement?

28 A map update should preserve the current zoom level while moving the center to a new coordinate. Which operation is most suitable?

29 An app monitors entry into and exit from a circular geographic area, including while it is not displaying the map. Which API is intended for this task?

30 A developer receives frequent callbacks while the map is being dragged and wants to begin an expensive search only after movement ends. Where should the search be triggered?

31 A WKWebView must open only links from example.com and cancel navigation to other hosts. Which API should be used?

32 A web view needs a JavaScript message handler named nativeApp. When must it be added to the WKUserContentController?

33 Which JavaScript expression sends the string ready to a registered native message handler named nativeApp?

34 An app calls webView.load(URLRequest(url: url)) with a plain http:// URL, but navigation is blocked on a default iOS configuration. What is the likely cause?

35 A controller wants to retrieve document.title after a page loads. Which method should it call?

36 Local HTML contains <img src="images/logo.png">, and the image must resolve relative to the HTML file's directory. Which loading approach is appropriate?

37 A web page calls window.open(...), but no new content appears. Which delegate method is commonly implemented to handle requests for a new web view?

38 A view controller registers itself as a script message handler and remains in memory after dismissal. Which change most directly addresses the common retention problem?

39 A page's loading indicator should stop only when navigation completes successfully. Which callback should update the indicator?

40 Two WKWebView instances need to share cookies and other website data. Which configuration choice supports this?

41 A controller must update a lightweight scale indicator continuously while the user pans, but perform an expensive server query only after the map movement finishes. Which delegate-method pairing is most appropriate?

42 An app calls setRegion(_:animated:) inside mapView(_:regionDidChangeAnimated:) whenever the center differs slightly from a desired coordinate. Users observe repeated delegate callbacks and camera jitter. What is the best correction?

43 A map shows thousands of point annotations. Clustering is enabled, but no clusters appear even when many annotations overlap. The delegate creates a new MKMarkerAnnotationView and assigns clusteringIdentifier only after the view has been displayed. Which change most directly fixes the issue?

44 An app displays a geodesic flight path using MKGeodesicPolyline, but the path is invisible. The overlay is successfully added and intersects the visible map rectangle. Which missing implementation is the most likely cause?

45 A map-based app needs the user's actual location for business logic. It currently treats the center of the map while .follow tracking mode is active as the user's position. Why is this unreliable?

46 A search request should run after a pan ends, but only when the newly visible area is meaningfully different. Comparing MKCoordinateRegion spans causes errors near the International Date Line. Which comparison is more robust?

47 A map uses mapView(_:viewFor:) to configure reusable annotation views. After reuse, some ordinary annotations display stale callout accessory controls that belong to other annotation types. Which practice prevents this defect?

48 An app sets both an MKMapView.CameraBoundary and an MKMapView.CameraZoomRange. It then requests an animated camera outside the boundary and below the minimum center-coordinate distance. What should the app assume?

49 A controller listens to mapView(_:didUpdate:) for user-location updates. Immediately after enabling showsUserLocation, the callback occurs, but userLocation.location is nil. What is the correct interpretation?

50 An app reloads visible data whenever mapView(_:regionDidChangeAnimated:) is called. During a rapid sequence of pans, responses arrive out of order and older results replace newer ones. Which design best preserves correctness?

51 In webView(_:decidePolicyFor:decisionHandler:), an app asynchronously checks whether a URL is allowed. Some navigations hang indefinitely. Which contract was most likely violated?

52 JavaScript calls window.open(url), and the navigation action received by the UI delegate has targetFrame == nil. The app wants the URL to load in the same web view. Which implementation is appropriate?

53 A view controller registers itself using userContentController.add(self, name: "bridge"). After the web view is dismissed, the controller never deinitializes. What is the most likely ownership problem?

54 An app injects a helper script into an isolated WKContentWorld. The page's own JavaScript cannot read a variable created by that script, although both execute in the same frame. What best explains this behavior?

55 A bundled HTML file loads successfully with loadFileURL(_:allowingReadAccessTo:), but its sibling CSS and image files fail. The read-access URL was set to the HTML file itself. What is the correct fix?

56 A top-level request receives an HTTP redirect and then fails before any document is committed. Which delegate callback should handle this failure rather than a failure occurring after content has started loading?

57 Two WKWebView instances must have completely separate persistent cookies and caches, even across app launches. Which configuration choice most directly establishes that separation?

58 An app registers a WKURLSchemeHandler and attempts to intercept normal https requests by registering it for the https scheme. What is the fundamental problem?

59 A WKWebView displays a user-controlled page. The app injects the user's raw name into evaluateJavaScript using window.setName('\(name)'). Names containing quotes break execution, and crafted names can execute code. Which approach is safest?

60 A web content process terminates while a form page is open. The app receives webViewWebContentProcessDidTerminate(_:). Which recovery assumption is unsafe?