iphone Interview Questions part-7

61- Which object manage the presentation of app’s content on the screen?

View controller objects takes care of the presentation of app’s content on the screen. A view controller is used to manage a single view along with the collection of subviews. It makes its views visible by installing them in the app’s window.

62- Which is the super class of all view controller objects?

UIViewController class. The functionality for loading views, presenting them, rotating them in response to device rotations, and several other standard system behaviors are provided by UIViewController class.

63-What is the purpose of UIWindow object?

The presentation of one or more views on a screen is coordinated by UIWindow object.

64-How do you change the content of your app in order to change the views displayed in the corresponding window?

To change the content of your app, you use a view controller to change the views displayed in the corresponding window. Remember, window itself is never replaced.

65-Define view object.

Views along with controls are used to provide visual representation of the app content. View is an object that draws content in a designated rectangular area and it responds to events within that area.

66-Apart from incorporating views and controls, what else an app can incorporate?

Apart from incorporating views and controls, an app can also incorporate Core Animation layers into its view and control hierarchies.

67- What are layer objects and what do they represent?

Layer objects are data objects which represent visual content. Layer objects are used by views to render their content. Custom layer objects can also be added to the interface to implement complex animations and other types of sophisticated visual effects.

68-What is App Bundle?

When you build your iOS app, Xcode packages it as a bundle. Abundle is a directory in the file system that groups related resources together in one place. An iOS app bundle contains the app executable file and supporting resource files such as app icons, image files, and localized content.

69-Define property?

It is used to access instance variables outside of class.

70-Why synthesized is used?

After declaring property we will have to tell compiler instantly by using synthesize directive. This tells the compiler to generate setter and getter methods.