Tuesday, September 30, 2014

Android information and devlopment resources

The Android javadoc is great reference material:

The Android Application components another important resource: 

The Android Welcome page

The Android Open Source Project

Linux Kernel: Standard services - Provides infrastructure mechanisms to manage mobile device resources
 •  Security
•  Memory, process, & thread management
 • Network & File I/O
 • Device driver framework (pluggable devices)
Android specific includes power management, Android Shared memory, low memory killer, Binder (Inter Process communication) , alarm driver, debugger, logger

Native System Libraries (C/C++ Native DK) core performance sensitive activities on device
System C library - (std os system calls such as process/thread creation, memory allocation, mathemetical) bionic libc
• Surface Manager  - (updating the display) display management
• Media Framework  - (playback) audio/video streaming
• FreeType  - library for rendering fonts
• Webkit - (rendering and display web pages ) web browser engine
• OpenGL ES, SGL - graphics engines
• SQLite - relational database engine
• SSL  - secure sockets layer

Runtime (part of System libraries layer)
Davlik virtual machine executes the android apps, code written in java compiled into series of bytecode files , Davlik dx program transforms java classes into single Dex bytecode file  (classes.dex). File packaged with other resources and installed on device. Dalvik VM executes the Dex Bytecode file when invoked on device.
Dalvik VM designed to be resource constrained environment with slower cpu, less memory, limited battery life
Core Libraries
• Core Java classes (building blocks)
• android.* (application lifecycle)
• java.*, javax.* (data structures, concurrency, I/O)
• junit.* (unit testing)
• org.*  (internet/ web services)
org.json.*, org.xml.*

Application Framework - reusable software that many applications will need
Package Manager  - Manages application packages on device such as info about apps
Window Manager  - Manages top-level window’s look & behavior (notification bar, main application window, sub-menus/dialogs)
View System  - common user interface elements such as Tabs, Lists, grids, text boxes, buttons, textview
Resource Manager - Manages non-compiled code resources: strings, graphics, & layout filesContent Providers  - Inter-application data sharing (i.e. databases)
Activity Manager - Application lifecycle & common navigation stack
Telephony Manager - State of telephony services
Location Manager - Access to system location services
Notification Manager - Notify users when events occur

Application - built in apps. Can substitute apps.
Home, Contacts, Phone, Browser, Email

Activity : Represents a single screen with a user interface (view user interface) - see Activity class
activity lifecycle or http://developer.android.com/reference/android/app/Activity.html
- Can be started by creating an Intent object & passing it to startActivity()
- Parameters can be passed as “extras” to the Intent used to start the Service
- Apps can have multiple Activities

Service -operation in background, can bind to other services or Activities. For performing long-running operations or to access remote resources. Extends the Service class.
Started Service – Often performs a single operation & usually doesn’t return a result to the caller directly
Bound Service – Offers a client-server interface that allows components to interact with the Service

Content Provider - Manages a shared set of application data , Never accessed directly,
but via a Content Resolver
Consistent access to data (i.e. Rest, Crud operations)
Data store backing options like SQLite, Web, File systems
Can consume data from other content providers
Extends the ContentProvider class

Broadcast Receiver - A component that responds to system-wide Intent broadcast announcements
- Supports complex Intent filtering
- delivered asynchronously to all receivers
Extends BroadcastReceiver class

Intents - messages (i.e. events) that link application components together


ADT Bundle:
latest android platform
eclipse and ADT plugin
latest image for emulator
additional dev tools

network/speed latencies
battery power
location coordinates

telnet localhost port# (i.e. 5554)

slow network:
network speed edge
network speed full
power capacity 5

power status not-charging

geo fix 0.0 40.0

sms send 3015555555 "msg"

call port number other emulator

Davlik debug Monitor service (DDMS) perspective

- file explorer
- logcat
- button in ddms to start and stop profiling at debug tracept

Open perspective -> Hierarchy view


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