iOS Developer

Automatic reference counting (ARC) If the compiler can recognize where you should be retaining and releasing objects, and put the retain and release statement in code.

By Using NSURLConnection , by starting connection or sending synchronous request.

App will crash with exception unrecognized selector sent to instance.

ARC represents Automatic Reference Counting. It is a Compiler level feature that simplifies the process of managing the lifetimes of Objects in Objective – C. ARC evaluates the Lifetime requirements of Objects and automatically includes appropriate Methods to be called during Compilation.

It is primarily used to identify one or more apps from a Unique Development team. It consists of a string divided into two parts. The string includes a Team ID and a Bundle ID Search String with a separator as a period. The Team ID is allocated by Apple and is different for every development team. A Bundle ID Search String is supplied by the App Developer.

The alloc keyword is used to create a New Memory Location in the System. However, it does not initialize it. In case of New keyword, it also helps to create a New Memory Location in the system. However, it can initialize the Contents unlike the alloc keyword.

A Protocol is used to define a list of required optional methods that a class needs to implement. If a class adopts a protocol, it must implement all the needed methods in the protocols it adopts. It is identical to an Interface in Java and also to a purely Virtual Class in C++. Cocoa uses protocols to support interprocess communication through Objective-C messages.

Interfaces enables defining features as small groups of closly related properties, methods, and events. It defines the events, properties and methods that classes can implement.

The maximum memory size is 256 Bytes to send a push Notification to Apple Server.

So this was the list of some important IOS interview questions and answers. If you found any information incorrect or missing in above list then please mention it by commenting below.

Inheritance is an Object Oriented Programming concept. It allows to develop a New Class that is reusable and can extend the behavior that is defined in another class.

Formal Protocols enables defining an Interface for a Set of Methods without any implementation. It is useful with DistributedObjects as they allow defining a protocol for communication between objects.

The languages used for iOS development are as follows:

☛ 1. Objective-C

☛ 2. .NET

☛ 3. C

☛ 4. HTML5

☛ 5. JavaScript

☛ 6. Swift

SAX (Simple API for XML):

☛ Parses node by node

☛ Doesn't store the XML in memory

☛ We can not insert or delete a node

☛ Top to bottom traversing

DOM (Document Object Model):

☛ Stores the entire XML document into memory before processing

☛ Occupies more memory

☛ We can insert or delete nodes

☛ Traverse in any direction

With Storyboards, all screens are stored in a single file. This gives you a conceptual overview of the visual representation for the app and shows you how the screens are connected. Xcode provides a built-in editor to layout the Storyboards.

☛ .storyboard is essentially one single file for all your screens in the app and it shows the flow of the screens. You can add segues/transitions between screens, this way. So, this minimizes the boilerplate code required to manage multiple screens.

☛ Minimizes the overall no. of files in an app.

☛ 1. Map :beautifully designed from the ground up (and the sky down)

☛ 2. Integration of Facebook with iOS

☛ 3. Shared photo streams.

☛ 4. Passbook - boarding passes, loyalty cards, retail coupons, cinema tickets and more all in one place

☛ 5. Facetime - on mobile network as wifi

☛ 6. changed Phone app - *remind me later,*reply with message.

☛ 7. Mail - redesigned more streamline interface.

☛ 8. Camera with panorama .

Xcode- 4.6.2

"atomic", the synthesized setter/getter will ensure that a whole value is always returned from the getter or set by the setter, only single thread can access variable to get or set value at a time

Specifies that retain should be invoked on the object upon assignment. takes ownership of an object

Mac- Mountain Lion

Instructs the compiler not to generate a warning if it cannot find implementations of accessor methods associated with the properties whose names follow.