Android architecture

Android Architecture
Outline
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Overview
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Applications
•
Application Framework
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Library and Android Runtime
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Linux kernel
Overview
Applications
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Set of necessary application
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Core application of Android include: Home,
Browser, Camera
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Your ability:
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Create new applications
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Replace default applications
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Use exist applications for your purposes
Ex: your application want to get a picture from
camera. So call Camera of Android through
intent component.
Application Framework

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Provide API to create UI
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Provide API to access system services
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Provide API to get resource
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Content provider
Application Framework
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UI API: views
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Typical view: view like Button, EditText,
ListView…
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ViewGroup: extends View but can contain
more than one view like LinearLayout,
FrameLayout
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Special View: Android support WebView and
MapView:
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WebView do the job of browser
•
MapView a special view use google map API
Application Framework
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System services:
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Get system services:

getSystemService(String)
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Total 20 system services
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Some services:
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LocationManager: get GPS location
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PowerManager: controll power
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SensorManager: access sensors
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WifiManager: manage Wifi access.
•
…
Application Framework
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Resources:
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Resource is non-code file like image, xml…
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Resource include application resource and
system resource:
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Application resource: files in res folder
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System resource: access through R.android
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To access drawable resource of Android, use
R.android.drawable.resourcename

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More resource name at eaming-
penguin.com/info/android_drawables/android_drawab
les.html
Application Framework
•
Content Provider
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Store and retrieve data and make it accessible
to all applications
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Is the only way to communicate between
applications
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Data kept by content provider can be modified
by:
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Adding new records
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Adding new values to exist records
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Batch updating exist records
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Deleting exist records
Libraries
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C/C++ libraries including:
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System C library
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Media libraries: support playback and record
many audio and video format including
MPEG4, H.264, MP3, AAC, AMR, JPG, and
PNG
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Sureface Manager: manages access to the
display subsystem and seamlessly
composites 2D and 3D graphic layers from
multiple applications
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LibWebCore: a modern web browser engine
which powers both the Android browser and
an embeddable web view
Libraries
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C/C++ libraries including:
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SGL: the underlying 2D graphics engine
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3D libraries: an implementation based on OpenGL
ES 1.0 APIs
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SQLite: a powerful and lightweight relational
database engine available to all applications
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FreeType: bitmap and vector font rendering
Android runtime
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Core java libraries
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Dalvik Virtual Machine
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Thread and memory manager
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Optimize memory usage
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Run many virtual machine
Kernel
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Linux kernel with system services:
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Security
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Memory and process management
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Network stack
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Provide driver to access hardware:
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Camera
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Display and audio
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Wifi
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…
The end