Appcelerator Interview Questions

Appcelerator is a mobile development stage specially designed for big enterprises who are looking to make applications with cross-platform working using a single code database. It mainly utilizes Javascript code for developing powerful components.

Appcelerator is a code interpreter. A developer firstly writes code using the conventional Javascript and then compiles it using an application with an Android or iOS operating system. After the application has compiled the code, Appcelerator’s native code that is included with the Javascript code interprets the initial code and commands it to a native language.

Appcelerator has the capability to develop a native application using simple HTML codes within an application that gives it an edge over other mobile application developers. The platform used by Appcelerator allows its users to complete control over cloud analytics. In addition, it is an open source with a very large community of users, which allows finding solutions to any problem with ease and within a stipulated time.

Some of the advantages of using Appcelerator include the following:

• It has an easy cross-platform development
• From a single code database, numerous application can be produced that can run simultaneously on a variety of phones
• It also allows the usage of the same application from different platforms

Some of the competitors of Appcelerator in the market include Xamarin, iFactr and Phone Gap.

The three main types of mobile application development programs include:

1. Native Apps: These applications are designed especially for specific devices. For example, applications for the Android operating system are written in Java. While on the other hand mobile application for the iPhone is written using Objective – C.
2. Web Apps: These websites provide extensive interactivity that is similar to native applications.
3. Hybrid Apps: Such applications use both the elements of native and web applications.

Push notification is a type of communication channel that allows an application to notify the user of a particular new message or a saved event without actually having to open the application. This can be easily achieved with a pop-up on the screen or with a sound.

The five basic steps involved in introducing push notification using Appcelerator include:

• Implementation of the cloud push module, which is achieved using the MQTT protocol
• Retrieve a required device token
• Login by the cloud user
• Subscribe to a channel
• The configuration of the push notification

Some of the disadvantages of a cross-platform include:

• It is heavy and requires a lot of space in comparison to native applications
• Over layering of the native environment does not give control over the final code that will be generated
• Cross-platform contains a lot of bugs that can eventually affect the productivity of the developer

Some of the common problems faced by mobile application developers include

• The market is loaded with a huge number of competitors
• Self – financing can be an issue
• Marketing of mobile applications is a herculean task
• Client requirements based on different screen size and the device can be a hurdle
• Application compatibility with different electronics and operating systems is a challenge
• Security issues is another challenge faced by mobile application developers

Security can be provided to various mobile applications by:

• Protecting the network connection right from the back end
• Putting different identification and authentication barriers at different locations
• Implementing good customer data security by using numerous encryption policies for mobile applications
• Having a strong API security strategy worked out at all times
• Running a test on mobile applications at regular intervals
• Spreading awareness to the users about protecting their devices

The steps involved in publishing a mobile application either to the App Store or onto Google Play include:

1. Enroll in the developer program of either of the operating system and create an account
2. Feed in different information such as application name, application icon, a short and brief description, ratings, keywords, copyright information, etc.
3. It is then reviewed by the Apple or Google play company
4. Finally, if there are not plausible rejections, the mobile application will get published

It is very important to avoid global variable while using Javascript to eliminate the risk of other scripts to overwrite a particular Javascript. It can result in maintenance issues and bugs.

Using the following coding, one can avoid using the global variable while coding with Javascript

var wrapperDemo= {
	x: 5,
y: function(myObj) {
}
};

The intent is the interface that is utilized by a mobile application developer when he/she tries to introduce and launch a new user from one interface to another. The intent is basically a system message or an event that goes along with the data that has been utilized by the first user.

Activity is a component of an application that is used to display or highlight the interface of a user.

Appcelerator cloud services are a wide range of pre-built and automatically scaled network services that can be used by the iOS or Android native operating systems.

Memory leak is a condition when a programmer who creates a memory in the heap forgets to delete it. It can be avoided by using the following coding:

/* Function without memory leak */
#include < stdlib.h > 
  
void f() 
{ 
   int *ptr = (int *) malloc(sizeof(int));  
   /* Do some work */  
   free(ptr); 
   return; 
}