PhoneGap Interview Questions

Phone Gap and its use:
It is open source framework, which enables the user for developing applications for the mobile phones with the use of web technologies like HTML5, CSS3 and JavaScript instead of the usage of C# for windows phones, Java for Android and Swift or Objective C for iOS.

The Phone Gap uses native project format for every platform.

In Phone Gap, we need the following things for different operating systems:

• For iOS: iOS SDK (System Development Kit), XCode is required.
• For Android:  Android SDK and ADT (Android Development Tools) plugin are required.
• For BlackBerry: Apache ant, Sun SDK, and BlackBerry Webworks SDK are required.
• For Symbian: Only System development toolkit is required.

Some of the events of Phone Gap are:

• Pause: The pause event is emitted when the user switches away from the app and it is put in the background
• Resume: The resume event is emitted when the app is brought back into the foreground. It is the inverse of pause.
• Deviceready: The deviceready event is emitted when the Cordova is fully loaded, and APIs of the device provide information which your applications are ready to use.
• Offline: The offline event is produced when the device goes offline.
• Online: The Online event is produced when the device goes online. It is the inverse of the offline event.
• Endcallbutton: The end call button also called a power button is used to end the call.
• Volumedownbutton: The volume button is used to manage the volume of the device’s sound.

Phone Gap:
Phone Gap is a framework for the mobile development. It is built on an open source called the Apache Cordova project.
This permits the user to write an app with HTML, CSS, JavaScript and then it is deployed to a wide range of mobile phones without losing the native app features.

Phone Gap Build:
It is the cloud-based service, which has been built on the top of the Phone Gap framework.

The available features in Phone Gap Cameraoptions are:

• Quality: This feature tells the user the quality of the saved image that ranges from [0,100]
• Destination Type: This feature helps you Choose formats of return value. Defined in navigator.camera.Destinationtype.
• Source Type: This feature sets the source of the image. Defined in navigator.camera.
• AllowEdit: Before selection of a picture, this feature lets you do simple editing of the image.
• Encoding Type: This feature determines the encoding type of returned image.
• TargetWidth: This feature allows you to set the image width.
• TargetHeight: This feature lets you set the image height.
• Media Type: Through this feature, you are able to set media type to be selected from.

As JavaScript is used on the front end, it has some drawbacks too.
Following are the few drawbacks of Phone Gap:

• Data processing: In comparison with JavaScript, the native language is much faster.
• Background processing:  The large number of applications are dependent on the background thread while Phone Gap API is built by using JavaScript that doesn’t support any multi-threaded options and hence it doesn’t support the background processing as well.
• Advanced graphics:  The applications that use the advanced graphics can easily be accessed by the third-party libraries and can also be done natively.
• Complex business logic: A large number of complex business applications can be accessed better with a native code.
• Access advanced native functionality: A large number of native API’s are not supported by the Phone Gap’s API.

The Phone Gap can access the following Storage options:

• Memory-store.js (MemoryStore)
• Is-store.js (LocalStorageStore)
• Websql-store.js (WebSqlStore)

The Phone Gap applications can be architected just like any other mobile web service. The radical difference in it is the initial HTML asset that is available locally, instead of the remote server.
The Phone Gap application loads initial HTML that requests the resource from the server or from the local environment. The Phone Gap supports single page web experienced model.

The most fundamental difference between AIR and Phone Gap is that the user is able to Build the AIR applications by using tools that are rooted in the Flash Platform, while the user can develop Phone Gap application by using CSS, HTML, and JavaScript.

The AIR application uses AIR runtime, which enables users to have the single code base, along with an exact and similar behavior expected through all the supported platforms.

The Phone Gap applications execute inside a native web browser component for every platform supported. For the separate platforms, Phone Gap may behave differently and accordingly.

• The Phone Gap is developed by the company Nitobi, which is based in Vancouver, Canada.
• Nitobi company was acquired in the year 2011 by Adobe Corporation.
• Later after an acquisition, Phone Gap technology was released by Adobe as an open source under Apache Cordova as the name.

The Mobile developers use Phone Gap because it lets the developers have a common codebase for all of the application codes.It does not force the developers from reinventing the wheel each time they move from one platform to the other.