Android Handheld Systems
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Transcript of Android Handheld Systems
ANDROID HANDHELD SYSTEMS
ANDROID
PLATFORM
ANDROID
DEVELOPMENT
ENVIRONMENT
THE ANDROID PLATFORM
A multi-layered software stack for building and running mobile applications
A software stack for mobile devices:OS kernel, system libraries, application frameworks & key apps.Android Software Development Kit (SDK) for creating apps.Libraries & development tools.
SecurityMemory & process managementFile & network I/ODevice drivers
Power managementAndroid shared memoryLow memory killerInter process communicationAnd much more
System C library->Bionic libc
Surface Mgr.->Display management
Media Framework->Audio/ Video
Webkit->browser engine
OpenGL->Graphics engines
SQLite->Relational->database engine
Two main components-> Core Java libraries-> Dalvik Virtual
Machine
basic java classes -- java.*, javax.*app lifecycle -- android.*Internet/Web services -- org. *Unit testing -- junit.*
App written in java compiled to Java byte code files.DX converts java byte code files to a single dex byte code file (CLASSES.DEX).
Dalvik executes DEX byte code file.
Designed for resource-constrainedenvironments
<>Slower CPU<>Less RAM<>Limited battery life
PACKAGE MANAGER
Keeps track of App Packages on Device.
WINDOW MANAGER
Manages the Windows comprising an App.
Sub window
NotificationBar
MainWindow
Tabs
Text View
Buttons
Provides common user interfaceElements.e.g., icons, text entry boxes, buttons and more.
Manages non- compiled resources, e.g. Strings, Graphics, and Layout files.
ACTIVITY MANAGERManages App Lifecycle and Navigation Stack.
Inter Application Data Sharing.
LOCATION MANAGERProvides Location and Movement Information.
NOTIFICATION MANAGERPlace Notification Icons in the Status Bar when
important events occur.
Notification
Standard apps include:Home – main screenContacts – contacts databasePhone – dial phone numbersBrowser – view web pagesEmail reader –compose & read email messages.
ANDROID DEVELOPMENT ENVIRONMENT
Your workbench for writing Android applications
Runs virtual devices
Can emulate many different device/ user characteristics, such as: Network speed/ latencies, Battery power, Location coordinates.
Emulate incoming phone calls & SMS messages
Can interconnect multiple emulators
Doesn’t require an actual phone
Hardware is reconfigurable
Changes are non-destructive
Can be very
slow
Some features
unavailable e.g.,
no support for
blue tooth or
USB connections
Performance /
user experience
can be misleading