I have had my fair share of developing “Kiosk Mode” or “Single Application Mode” applications for Android. The idea is to run only one custom app and prevent any other applications to run (or only whitelisted applications). In this blog post I would like to share the approaches that you can take and the possible challenges you’ll face while developing these type of applications. This is a high-level overview of the effort involved, and not meant to provide code examples which will be beyond the scope of the post.

Volley is the new Swiss Army Knife of Android Developers, it provides some nice utilities which makes the networking for Android apps easier and faster. The good thing about Volley is that it abstracts away the low level details of what HTTP client library is being used under the hood and helps you focus on writing nice and clean RESTful HTTP requests. Additionally all requests in Volley are executed asynchronously on a different thread without blocking your “main thread”.

In Android the screen that appears when the phone starts is called “Launcher Screen”. It is possible in Android to write custom launcher apps which can be used as a replacement for the default launcher app that comes bundled with the phone. Developing a launcher app is no different than developing any other Android application, in fact both are same. In this post I’ll share what you need to do to write your own custom launcher application.

If you have ever developed an Android application which sends and consumes large amount of JSON data without gzipping then this post is probably for you. This is a very simple optimization technique that you can implement which vastly reduces the network latency and also benefits the users as well as internet. The idea is to transfer less data over the network and once you do that, it improves the speed of your application and helps users by reducing their mobile data usage (i.e saves $$$ in fact).

It has been said many times before by a lot of great people from the world of Computer Security and I am going to say it again, yes again, even though you don’t like it!

Do not use same password everywhere

Why not? No one can guess my password, it’s ultra-strong, it contains letters, digits and even some special characters, I have even tested it with Password Strength Meter, so it’s simply unbreakable :–).

Indeed your password is unbreakable and even unguessable but there is a very good chance that you’ll lay it bare without even knowing it. Surprised right? Want to know how is this possible? Keep reading, I am going to tell you about the possibilities.

Well, the title of the post may not be descriptive enough of the complexity that we dealt with in one of our recent projects. Before I delve deeper into the actual problem, let me give you some background of what we’re trying to achieve. We’ve been working on an Android application for some time which is going to be installed in kiosks or in cabs mainly on Android tablets (currently Android 2.2 devices), basically this is a sort of in-cab entertainment system where you can listen to music, watch videos, latest movie trailers and promos, read latest news, search places and find them in maps. You may think what’s so complicated about it? Well this app is an Android Homescreen application and this is going to be the only application that users can access from the tablets and above all it’ll be remotely managed.

The term remotely managed means that the app will be automatically updated over the air, there will be a provisioning server where the admins can publish/upload a new build, and that build will automatically be installed in the devices. Other than that the device can also be remotely restarted or shut down. The content that users can access or play using the app is stored in the device for faster access, and that content is synced (i.e. updated) periodically from a remote content syncing server. All of these are happening over the internet and the devices are equipped with a 3G chip, which makes it easier to download large amount of data with a decent network speed, else the content syncing would be a real pain. Below is the list of rough requirements that we had:

• The main app will be the only app which users can access.
• Automatic update over the air using a provisioning server.
• Sync content from a remote content syncing server.
• Report Crashes and device health statuses to the server.

PhoneGap is an open-source cross-platform Mobile Application development framework by Nitobi Software (now Adobe) which allows web developers to build mobile apps using HTML, CSS and JavaScript.

The PhoneGap project has been moved to Apache Incubator and now it is known as “Apache Callback”. PhoneGap project is divided into several sub-projects where each one represents a separate platform. In order to develop for iPhone and iPad, you need Mac OSX and XCode installed, similarly for Android you need Google Android SDK, Eclipse ADT Plugin, Ant as well as Eclipse IDE.

The official project detail can be found here Apache Cordova. It is currently hosted in GitHub and once the Apache infrastructure is ready it will be moved there.

In JavaScript, there’s an operator called new which we use to create an instance of an object (i.e Constructor function). So, what does new do? Well, it ensures that you always get an object when you use it with a constructor function. By the way, there’s no difference between a constructor function and a normal function, both are same. The term constructor function is used to indicate that we can create an object of that type using the new operator.

Frontend engineering as it stands today is a bit of vague and unspecified territory, it’s still not clearly understood may be because of the lack of clarity around stuffs a frontend engineer does. To simply put, frontend engineering means understanding the browsers best, the work of a frontend engineer is what you see when you do “view source”. So, how can you become a frontend engineer? In this post I’ll list down some of the things that a would be frontend engineer should know about. Frontend engineers write software using HTML, CSS and JavaScript, and yes I meant ‘writing software’, because if you look at modern day web applications like Gmail, Yahoo! Mail, Google Wave all are complex applications which involves significant amount of JavaScript, CSS, HTML and other technologies. So basically it means a frontend engineer should be specialized in HTML, CSS and JavaScript.