Professional Mobile Developer Interview Preparation Guide

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ANR stands for "Application Not Responding". It's a dialog box that appears when an application doesn't respond for more than 10 seconds (sometimes it can be less than 10 seconds). The ANR dialog box offers the user the option of either closing the app or waiting for it to finish running.

A follow-up to the previous question, there are a number of possible answers here. What you want to hear is that you want as little work done as possible on the main thread, also known as the "UI thread". Since that is the core single thread that your application runs on, you would want to keep activities that require more complex computations or network and database connections, for example, on separate worker threads so as not to slow down the main thread.

Scoping starts with a long, hard look at the device. Mobile devices offer different form factors, screen size and resolution, computing power and functionality. They run different operating systems and have other methods of retrieving data such as wifi or 3G.
The challenge is to understand the device and how it will be used to the best advantage: focus on the benefits of the device, such as size and portability, and ensure that the user experience will be optimised.

You want to find out that this person will seek to truly understand what you are trying to accomplish with your app, and the functionality. The following items are good to hear:

★ Objective statement or purpose of the app for the app publisher
★ Description of the target audience or user demographics
★ Any existing apps that it might be similar to
★ Wireframes
★ Artwork; The best developers will say they require the artwork to be completed before development. This avoids delays, and helps the developer understand the look, feel and branding you are trying to achieve.

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

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.

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

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.

An app is said to be in 'not running' state when:
1) It is not launched.
2) It gets terminated by the system during running.

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.

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.

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

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.

UIKit classes should be used only from an application's main thread. Note: The derived classes of UIResponder and the classes which manipulate application's user interface should be used from application's main thread.

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.

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

SBJson framework is supported by iOS. It is a JSON parser and generator for Objective-C. SBJson provides flexible APIs and additional control that makes JSON handling easier.

iOS 4 and above supports multi-tasking and allows apps to remain in the background until they are launched again or until they are terminated.

iOS Simulator can be used to test mobile applications. Xcode tool that comes along with iOS SDK includes Xcode IDE as well as the iOS Simulator. Xcode also includes all required tools and frameworks for building iOS apps. However, it is strongly recommended to test the app on the real device before publishing it.

AIDL supports charSequence, list, map, string, and all types of native java data types.

src:
This contains the .java source files for your project.

gen:
contains the .R file, a compiler-generated file that references all the resources found in your project. You should not modify this file.

bin:
contains the Android package files .apk built by the ADT during the build process and everything else needed to run an Android application.

res/drawable-hdpi
This is a directory for drawable objects that are designed for high-density screens.

res/layout
This is a directory for files that define your app's user interface.

res/values
This is a directory for other various XML files that contain a collection of resources, such as strings and colors definitions.

AndroidManifest.xml
This is the manifest file which describes the fundamental characteristics of the app and defines each of its components.

Android Interface Definition Language. It offers to define the client's interface requirements and moreover a service in order to communicate at same level with the help of inter process communications.

Also referred to simply as Widgets, App Widgets in the Android world are miniature views that are embedded within Android apps and typically display periodic updates. Music players, weather updates, sports scores, and stock price changes are all examples of data that can be displayed in an App Widget.

These are code names for Android releases, and are well known throughout the Android community. Your developer should be familiar with them. Ice Cream Sandwich was Android version 4.0 (API level 14) released on October 18, 2011. KitKat refers to Android version 4.4 (API level 19), released on October 31, 2013.

This question is really to weed out the beginners who may not be as familiar with the different Android releases and that changes within each. You really want your developer to be in tuned to the Android updates so they know what's possible, how to best implement what you are asking, and where things are headed in general.

Containers holds objects and widgets together, depending on which items are needed and in what arrangement they need to be in. Containers may hold labels, fields, buttons, or even child containers, as examples.

The developer should name at least 4 of these 6 items below, as these are essential within each Android project:
1) AndroidManifest.xml
2) build.xml
3) bin/
4) src/
5) res/
6) assets/