AN4430 datasheet(10/42 Pages) STMICROELECTRONICS

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Android Application Overview

AN4430

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DocID025722 Rev 1

defined a set of available features, meaning that some features are not available for lower

API revision. As example NFC functionality appears at API level 9 restricted to NDEF

message access and has been improved since this API revision. Figure 2 Android revision

with corresponding API levels shows the whole android revision and the associated API

levels.

Figure 2. Android revision with corresponding API levels

1.3

Android Application Introduction

1.3.1

Application fundamentals

Android application is primarily written in java programming language. Source code is

converted to java class files by the Java compiler. Then, Android SDK converts these Java

classes into optimized Dalvik executable file(s) (.dex suffix). Using the AAPT tool, Dex files

and application project related resources are packaged into an APK: android package,

which is an archive file with an “.apk” suffix. The APK generated file self contains all the

contents of an android application. The resulting APK file can be deployed to an Android

device by either the ADB tool in developing step or by the google android store once the

final application is published in release mode. The APK package is used by the Android

powered devices to install the application with a unique user and group ID. Each application

file is private to this generated user and other applications cannot access this file.

When launched by the operating system, the application runs, in its own process, upon its

own Dalvik virtual machine and is totally isolated from other running applications. In this

way, each application has access only to the components that it requires to do its work.

However, applications can share data between themselves either by giving the same Linux

AN4430 Datasheet(PDF) 10 Page - STMicroelectronics