subject: Fundamentals Of Android Application Development [print this page] Android application development is now in booming with prospects as presently there have been more than 600,000 applications developed for the Android platform. With such statistics, it is quite evident that application development for Android will keep rising.
Applications for Android devices are first written in the language of Java programming. The code is then compiled, by the tools of the Android SDK, and placed into something known as the Android package. This is an archive file that can be identified by its suffix .apk.
The entire code that resides within this file is one complete application. This is the file that is used by users to download into their devices. When the application has been installed into the device, the application has its own working process.
Every application in the device is accessed to the components it needs in order to function. The general setup is as follows,
"The Android platform is a Linus system of multiple users where each application is considered to be a user.
"Every application is allotted a specific Linux ID. The system is organized in a way that the files in a particular application are arranges in order for the right application to access them (through the ID allotted).
"Every application has its code run without interruption from any other application. This means that every process has a separate Virtual Machine.
"Furthermore, it also suggests that every application operates in its very own process in Linus. This means that Android begins the procedure when the application is needed and shuts it down when it"s not.
This way, the working procedure of applications makes it more secure because each application is entitled to access only certain components and not those that it is not permitted to. There is, however, a way for applications to share data and for a certain application to be permitted to access services from the system.
There is provision placed for two applications to have the same allotted ID. In such cases, these applications would have access to each other"s files. Also, these applications would work with the same Virtual Machine.
Certain applications can appeal for access to other data like the contacts of the user, camera, and information on storage and so on. But it is of course mandatory that each application is permitted by the user alone.
Android Application Components
The basic building blocks of an application are the Android application components. Every component has a specific function and lifecycle that defines its role. There are four different components,
Activity: This component represents a single screen that has a user interface. For example, for an email application, compose email is an activity and showing new emails is another activity. They are independent of each other.
Service: This component operates to run long running processes.
Content provider: This manages the set of shared data of the application.
Broadcast Receiver: It responds to the announcements made by the system.
Application Developers are experts in utilizing the various combinations and coordinating them in order to get the most effective applications.
