Feb

IOS Interview Questions
- PD Singh
- 22nd Feb, 2023
- 807 Followers
IOS Interview Questions
Whether you are a candidate or an interviewer you may always find it difficult to lay your hands on the best kind of questions for an interview, especially such an important one. iOS interview questions are all technology-based that is very straightforward if you have a basic idea of what you are dealing with. Any amount of preparation is a waste of time if you are not through with the basics. Here is a list of important questions that will refresh your brain to prepare for the iOS interview.
The questions will give you an idea about the pattern and the right way to answer the questions that may be thrown your way during the interview. So, without adieu lets' start with the questions and answers that may come in the iOS interview.
Read Few Important iOS Interview Questions and Answers
IOS Interview Questions
1) What is the method for preventing the QuickTime Player from capturing streaming videos of iOS 8 apps on Yosemite while screen recording is on?
The HTTP Live Streaming tech (HLS) from Apple allows you to send and receive on-demand and live video and audio media on your iPad, iPhone, Apple TV, Mac and PC. HLS uses the very same properties and procedures which drive the web and thus, lets the user make use of content with the help of ordinary content delivery networks and web servers. HLS is exclusively designed for high reliability and it dynamically modifies itself to suit the network conditions. This is done by optimization of playback according to the available connection speed offered by wired or wireless devices.
2) How can a user respond or react to the state transitions on the app?
For instance:
- The method applicationDidBecomeActive( ) can be employed to arrange the app to run as the fore app.
- The method applicationDidEnterBackground( ) can be employed for the execution of some code during the background runtime of the app and the exercise may be put on hold at any time.
- The method applicationWillEnterForeground( ) can be employed when the app is moving into the foreground and shifting out of background and some code needs to be executed.
- The method applicationWillTerminate( ) is called to action when the app is nearing termination.
3) What are extra features added in iOS 9?
It is capable of creating contextual reminders and even employ search to find a particular photo or video from the gallery in innovative ways. It does more than ensuring that we are where we need to be at any particular time. Going right from the home screen of the device shows “Siri Suggestions”. This screen is home to all your favourite apps and contacts, restaurants, information about the location and more important news from the web.
For more extensive search, Siri can display capabilities for deeper search and come up with results like videos, sports scores, content from other third-party apps, and more. Simple conversations and calculations can also be done using the handy search tools available on iPad or iPhone. Many inbuilt apps have also been upgraded for improved performance.
- ✓ The app for Notes has new sketching features and checklists.
- ✓ The maps include transit directions in addition to the usual features.
- ✓ File attachments are possible with Mail.
- ✓ The brand new app for News intelligently studies your interests and then personalizes the news to relevant content which is of interest to you.
- ✓ The transaction app, Apple Pay, now comes with added store credit cards as well as loyalty cards.
- ✓ iOS 9 has updated the leading app “Passbook” to “Wallet”.
- In addition to these, the operating system has updated to wireless CarPlay support for an elective app from iCloud Drive, San Fransico type font, inbuilt two-factor type authentication as well as elective longer passwords for improved security.
4) How is retain different from assign?
5) What is managed object context and what are its functions?
- Multiple copies of any object could exist in various contexts but a singular instance of the managed object exists in not more than one context.
The chief functions of a managed object context comprise of the following:
- Management of life cycle: In this case, the context delivers proof, undo/redo and handling of the inverse relationship.
- Notifications: These denote the context posts notices at different points which can be observed from another part of the application.
- Concurrency: When the Core Data makes use of confinement of threads or serialized queues in order to protect the managed object contexts and the managed objects too.
6) How are non-atomic and atomic properties different? Which one is the default property for synthesized properties? When would a user operate one over the other?
7) Does Objective-C contain private methods?
If you are really looking for a private method then you will have to add an unnamed category /local category/class extension in the class and add the method in the category and define it in the class.m.
8) Explain IGListKit?
This way we can say goodbye to UICollectionViewDatasource, instead, we can use an IGListAdapterDataSource with IGListAdapter. The data source provides the array of Selection Controllers and doesn’t return counts or cells.
The Section Controllers are used to control cells and configure within the given collection view section.
9) What is URLSession?
- Getting data to memory also known as Data task
- Downloading file to disk also known as Download tasks
- uploading a file from the disk and then receiving the response as data in the memory, which is known as Upload tasks
10) How to download images in iOS?
11) Define Iterator Protocol?
12) What is OAuth?
13) Provide an explanation for rethrows keyword
14) Describe @objc inference
15) Ellaborate Viper Architecture
The main advantage of viper architecture is its ability for communication from one entity to another that is made known through protocols. The idea is to isolate the app’s dependencies by balancing the delegation of responsibilities among the entities.
16) Define Content offset
17) What is NSLayoutAnchor?
There are three subclasses of NSLayoutAnchor:
- NSLayoutYAxisAnchor This subclass is used to create vertical constraints
- NSLayoutDimension This subclass is used to create the width and height constraints
- NSLayoutXAxisAnchor This subclass is used to create horizontal constraints
18) What’s the difference between MKAnnotation and MKPointAnnotation?
We can use MKPointAnnotation directly if we want our own business logic on the annotation.
19) What is Main Thread Checker?
20) What is the difference Stack and Heap?
Our code takes up some space in the iOS. The size of this is sometimes fixed and sometimes it can change according to what the user will enter during the program. Basically, we have two different methods because of this difference: Stack and Heap.
A stack is used and automatically removes itself from memory after work is finished. But in Heap, the user could do it by writing manual code for deleting from memory.
Stack: | Heap |
• A stack is easy to use. | • Compared to Stack, it is quite slow. |
• It’s kept in RAM on the computer. | • It creates memory problems if not used correctly. |
• Created variables are automatically deleted when they exit the stack. | • Variables are used with pointers. |
• It is quite fast compared to Heap. | • It is created at runtime. |
• Constructed variables can be used without a pointer. |
21) Provide a good explanation for VIP (Clean-Swift) Architecture
22) Define Decoding or Deserialization and Encoding or Serialization,
In swift we use the Codable protocol that a type can conform to, to declare that it can be encoded and decoded. It’s basically an alias for the Encodable and Decodable protocols.
23) What is the purpose of using IBAction and IBOutlet?
IBAction resolves to void whereas IBOutlet resolves to nothing, but yes, they signify to Xcode and Interface Builder that these methods and variables can be used in Interface builder to link UI elements to your code.
24) Explain AlamoFire Benefits
- AlamoFire is needed to create a route, which means that if we create request then it can be executed to the server by one static function.
- It can provide methods for chaining for the request that is returned. This makes it easy for adding handling responses and headers.
- It also has the number of response handlers, which is generally returned in parse JSON, text, binary form, and even multiple of each can be used for a given request.
- AlamoFire also has a method for chaining that allows response validation. We can call validation to check for the status code of the HTTP response, the content type, or any custom validation you might need to do for our app.
- AlamoFire gives a couple of URLRequestConvertible, protocols, and URLConvertible. These protocols can be passed on while creating a request.
- AlamoFire is known to provide extensions that can be passed on to create the request.
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