26-12-2012, 04:29 PM
Android Introduction
Android.ppt (Size: 2.87 MB / Downloads: 77)
What is Android?
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.
Android is an open source operating system, created by Google specifically for use on mobile devices (cell phones and tablets)
Linux based (2.6 kernel)
Can be programmed in C/C++ but most app development is done in Java (Java access to C Libraries via JNI (Java Native Interface))
Supports Bluetooth, Wi-Fi, and 3G and 4G networking
Android S/W Stack - Libraries
Including a set of C/C++ libraries used by components of the Android system
Exposed to developers through the Android application framework
Publishing to Android Market
Requires Google Developer Account
$25 fee
Link to a Merchant Account
Google Checkout
Link to your checking account
Google takes 30% of app purchase price
Android Design Philosophy
Applications should be:
Fast
Resource constraints: <200MB RAM, slow processor
Responsive
Apps must respond to user actions within 5 seconds
Secure
Apps declare permissions in manifest
Seamless
Usability is key, persist data, suspend services
Android kills processes in background as needed
Android Applications
Applications are defined to Android via the android manifest file, located in the root of the Eclipse project definition (AndroidManifest.xml)
Double clicking on the AndroidManifest.xml file in the Eclipse project will open the Manifest editor.
The manifest editor is the normal way of creating and modifying the manifest file (defining the app to the system)
An Android application is a collection of activities, an activity correlates to a screen or form that is presented to the user.
The HelloAndroid is a simple one screen app that is essentially the same as a Java app run in a terminal/command window. Its AndroidManisest.xml file reflects this :