iphone Interview Questions and Answers Freshers and Experinced

iphone Interview Questions and Answers Freshers and Experienced 

21.Which API is used to write test scripts that help in exercising the application’s user interface elements?

UI Automation API is used to automate test procedures. Tests scripts are written in JavaScript to the UI Automation API.  This in turn simulates user interaction with the application and returns log information to the host computer. 

22.Explain about the applications that can be used with iPhone ?

Technology, Entertainment and Design (TED): Allows to watch and listen to world’s most fascinating people have to say, all on the iPhone.

23.What are the tools required to develop iOS applications?

iOS development requires Intel-based Macintosh computer and iOS SDK.

24.Name the framework that is used to construct application’s user interface for iOS.

The UIKit framework is used to develop application’s user interface for iOS. UIKit framework provides event handling, drawing model, windows, views, and controls specifically designed for a touch screen interface. 

25.What is iPhone reference library?

iPhone reference library is a set of reference documents for iPhone OS.

It can be downloaded by subscribing to the iPhone OS Library doc set.

Select Help>Documentation from X code, and click the subscribe button next to the iPhone OS Library doc set, which appears in the left column.

26.What are sensors in iPhone?

The proximity sensor immediately turns off the display when the iPhone is lifted to ear. With this sensor the power is saved and accidental dialing is prevented.

The display is automatically brightens the iPhone by the ambient light sensor when the sunlight or bright rooms and dims in darker places.

27.How can an operating system improve battery life while running an app?

An app is notified whenever the operating system moves the apps between foreground and background.  The operating system improves battery life while it bounds what your app can do in the background. This also improves the user experience with foreground app.

28.Why an app on iOS device behaves differently when running in foreground than in background?

An application behaves differently when running in foreground than in background because of the limitation of resources on iOS devices.

29.Which framework delivers event to custom object when app is in foreground?

The UIKit infrastructure takes care of delivering events to custom objects. As an app developer, you have to override methods in the appropriate objects to process those events.

30.When an app is said to be in not running state?

An app is said to be in ‘not running’ state when:

 it is not launched.

 it gets terminated by the system during running.

31.Assume that your app is running in the foreground but is currently not receiving events. In which sate it would be in?

An app will be in InActive state if it is running in the foreground but is currently not receiving events. An app stays in InActive state only briefly as it transitions to a different state.

32.How can you respond to state transitions on your app?

On state transitions can be responded to state changes in an appropriate way by calling corresponding methods on app’s delegate object.

For example:

applicationDidBecomeActive method can be used to prepare to run as the foreground app.

applicationDidEnterBackground method can be used to execute some code when app is running in the background and may be suspended at any time.

applicationWillEnterForeground method can be used to execute some code when your app is moving out of the background

applicationWillTerminate method is called when your app is being terminated.

33.List down app’s state transitions when it gets launched.

Before the launch of an app, it is said to be in not running state.

When an app is launched, it moves to the active or background state, after transitioning briefly through the inactive state.

34.Who calls the main function of you app during the app launch cycle?

During app launching, the system creates a main thread for the app and calls the app’s main function on that main thread. The Xcode project’s default main function hands over control to the UIKit framework, which takes care of initializing the app before it is run.

35.Give example scenarios when an application goes into InActive state?

An app can get into InActive state when the user locks the screen or the system prompts the user to respond to some event e.g. SMS message, incoming call etc.

36.When an app is said to be in active state?

An app is said to be in active state when it is running in foreground and is receiving events.

37.Name the app sate which it reaches briefly on its way to being suspended.

An app enters background state briefly on its way to being suspended.

38.Assume that an app is not in foreground but is still executing code. In which state will it be in?

Background state.

39.An app is loaded into memory but is not executing any code. In which state will it be in?

An app is said to be in suspended state when it is still in memory but is not executing any code.

40.Assume that system is running low on memory. What can system do for suspended apps?

In case system is running low on memory, the system may purge suspended apps without notice.

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