Introduction
to Android
Tuesday, December 4, 12
Introduction to Android
• What is Android?
• Installation
• Getting Started
• Anatomy
Application
of an Android
• Life Cycle of an Android
Application
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What is Android?
• Released in Nov. 2007 – rumored to be some kind of GPhone
• Open, free mobile platform with a complete software stack
• Operating system
• Middleware
• Key mobile applications
• Developed by the Open Handset Alliance
• Built on the open Linux kernel
• Custom Dalvik virtual machine for mobile environments
• Applications written in Java
• Open source; Apache v2 open source license
• Applications can access all core functionalities of a mobile device
• (Nearly) no differentiation between core and 3rd party applications
• Can be extended to incorporate new technologies
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Open Handset Alliance
• Group of more than 30 technology and mobile
companies led by Google
• Mobile Operators, e.g. China Mobile, KDDI, NTT
DoCoMo, TMobile,
• Sprint Nextelk, Telefonica
• Semiconductor Companies, e.g. Broadcom, Intel,
Nvidia, Qualcomm, SiRF, Texas Instruments
• Handset Manufactureres, e.g. HTC, LG, Motorola,
Samsung
• Software Companies, e.g. eBay, Google,
• Goal: „to accelerate innovation in mobile and
offer consumers a richer, less expensive, and
better mobile experience “
• Android as the first project towards an open
and free mobile experience, but also
commercial deployment
• URL: www.openhandsetalliance.com
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Open Handset Alliance
• Group of more than 30 technology and mobile
companies led by Google
• Mobile Operators, e.g. China Mobile, KDDI, NTT
DoCoMo, TMobile,
• Sprint Nextelk, Telefonica
• Semiconductor Companies, e.g. Broadcom, Intel,
Nvidia, Qualcomm, SiRF, Texas Instruments
• Handset Manufactureres, e.g. HTC, LG, Motorola,
Samsung
• Software Companies, e.g. eBay, Google,
• Goal: „to accelerate innovation in mobile and
offer consumers a richer, less expensive, and
better mobile experience “
• Android as the first project towards an open
and free mobile experience, but also
commercial deployment
• URL: www.openhandsetalliance.com
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Android Features
• Application framework enabling reuse and replacement of components
• Dalvik virtual machine optimized for mobile devices (register based)
• Integrated browser based on the open source WebKit engine
• Optimized graphics powered by a custom 2D graphics library; 3D graphics
based on the OpenGL ES specification (hardware acceleration optional)
• SQLite for structured data storage
• Media support for common audio, video, and still image formats (MPEG4, H.
264, MP3, AAC, AMR, JPG, PNG, GIF)
• GSM Telephony (hardware dependent)
• Bluetooth, EDGE, 3G, WiFi, NFC (hardware dependent)
• Camera, GPS, compass, accelerometer, gyroscope (hardware dependent)
• Rich development environment including a device emulator, tools for
debugging, memory and performance profiling, and a plugin for the Eclipse IDE
Source: http://code.google.com/android/index.html
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Android Architecture
Source: http://code.google.com/android/index.html
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Android Architecture
Source: http://code.google.com/android/index.html
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Android Architecture
Source: http://code.google.com/android/index.html
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Android Architecture
Source: http://code.google.com/android/index.html
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Linux Kernel
• Linux kernel version 2.6
• Abstraction layer between hardware and the
software stack
• Core services
• Memory management
Security
• Process management
• Network stack
• Driver model
•
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Libraries
• C/C++ libraries used by various Android components
• Developers can use their capabilities through the
application framework
• Includes:
• WebKit/LibWebCore: web browser engine
Media Libraries: includes MPEG4, H.264, MP3, JPG, PNG,
• SQLite: relational database engine
• Libraries/engines for 2D and 3D graphics
•
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Android Runtime
• Core libraries provide Java functionalities
• Dalvik virtual machine relies on Linux kernel for e.g.
threading or low-level memory management
• Devices can run multiple Dalvik VMs, every Android
application runs with its own instance of Dalvik VM
• VM executes optimized Dalvik Executable files (.dex)
• Dx-tool transforms compiled Java-files into dex-files
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Applications /
• Core applications, e.g. contacts, mail, phone, browser,
calender, maps, …
• Full access to all framework APIs for core applications
• Simplified reuse of components
• Applications written in Java
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Core Android Packages
• android.util
• contains various low-level utility classes, such as specialized container classes, XML utilities, etc.
• android.os
• provides basic operating system services, message passing, and inter-process communication.
• android.graphics
• is the core rendering package.
• android.text, android.text.method, android.text.style, and android.text.util
• supply a rich set of text processing tools, supporting rich text, input methods, etc.
• android.database
• contains low-level APIs for working with databases.
• android.content
• provides various services for accessing data on the device: applications installed on the device and
their associated resources, and content providers for persistent dynamic data.
• android.view
• is the core user-interface framework.
• android.widget
• supplies standard user interface elements (lists, buttons, layout managers, etc) built from the view
package.
• android.app
• provides the high-level application model, implemented using Activities.
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The Tasteful Android
Version History
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2008
1.0
• Many elements where
there from the start
• No widgets yet
• Notification Bar
• No tasty name yet ;)
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html MMI2 13
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2009
1.5 (Cupcake)
• Onscreen-Keyboard with
„Autocomplete“
• Screen switch Animations
• Videoupload
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://images3.wikia.nocookie.net/__cb20110428020146/uncyclopedia/
images/4/4b/Cupcake.jpg
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2009
1.6 (Donut)
• Screenshots on the android
market
• Voice Search
• WVGA resolutions
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://images4.wikia.nocookie.net/__cb20120101131538/smosh/images/b/
b2/Pink_frosted_sprinkled_donut.jpg
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2009
2.0 (Eclair)
• Speed improvements
• More screen resolutions
(dip)
• Camera flash support
• Live wallpapers
• Multitouch support
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://gadgetsteria.com/wp-content/uploads/2010/01/eclair.jpg MMI2 16
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2010
2.2 (FroYo)
• Speed and performance
increase
• Flash 10.1 support
• Installing apps on SD-Card
• Tethering
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://www.talkandroid.com/wp-content/uploads/2010/08/FroYo.jpg?
3995d3
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2010
2.3 (Gingerbread)
• Dual-Core-Unterstützung
• NFC
• HTML5
• bessere Garbage Collection
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://www.exclusivelyfood.com.au/uploaded_images/
gingerbread7-744309.JPG
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2011
3.X (Honeycomb)
• Tablet Optimized
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://phandroid.s3.amazonaws.com/wp-content/uploads/2010/08/honey-
comb-l.jpg
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2011
4.X (Ice Cream
Sandwich)
• 2.x and 3.x to one version
• Face recognition
• Multitasking
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://www.blogcdn.com/www.engadget.com/media/
2011/05/11x05101719.jpg
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2012
4.1 (Jelly Bean)
• Performance and rendering
improvements
• Smoother UI (touch
anticipation, fixed
framerate @60fps)
• Gesture based (and
predictive) text entry
• Google Now (Siri-like)
http://www.chip.de/bildergalerie/Android-Timeline-Alle-Versionen-alle-
Einfuehrungs-Handys-Galerie_53930690.html
http://2.bp.blogspot.com/-VYTzIzPtI_o/TbD6WqeBNII/AAAAAAAABfo/
sKcKyGozpxg/s1600/jellybelly-flavor-guide.jpeg
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Installing The SDK
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Installing SDK
• Please follow instructions from the
Android doc
• Download and install the Android
SDK
• SDK includes documentation, tools
and examples
• Set up your IDE; Eclipse (Java EE)
recommended
• Install Eclipse Android
Development Tools (ADT) plugin,
connect it with the Android SDK
and Download your Platforms
http://developer.android.com/sdk/index.html
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Installing SDK
• Create an Android project
• Standard Eclipse procedure
• Automatically creates folders and a Manifest file
• Can also be used to create a demo project
• Set up a launch configuration
• Run application from menu or
• Define settings for run configuration (project, activity, emulator
options, …) from Run > Open Run Dialog >
• Run Android application in emulator
• Be Patient! The emulator takes while to boot up.
• Keep it open once it was started!
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The Nexus One
Source: Wikimedia Commons
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The Nexus One
Source: Wikimedia Commons
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Hello World
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Hello Android I
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Hello Android II
Source: http://code.google.com/android/index.html
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Hello Android III
Source: http://code.google.com/android/index.html
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Hello Android IV
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Hello World
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Anatomy of an Android Application
• 4applications
main building blocks for Android
• Activity
• Intent Receiver
• Service
• Content Provider
• AndroidManifest.xml lists all components of
an application, their capabilities and
requirements
Source: http://code.google.com/android/index.html
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Activity
• Single, focused thing or task
• Extends the Activity base class
• Refers to a single screen in a (multi-screen)
application
• Displays a UI, interacts with user, responds to
events
• •2 main methods:
onCreate(Bundle): initialization of activity, set UI,
…
• onPause(): leaving an activity
• Moving through screens by starting other
activities
• Activities managed by activity stack
• New activity put on top of the stack
• 4 states: active/running, paused, stopped,
killed/shut down
Source: http://code.google.com/android/index.html
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Intents and Intent Filters
• •Intent
Abstract description of an operation/action to be performed
• Mostly used for launching activities; “glue between
activities”
• Action: general action to be performed, e.g. VIEW_ACTION,
EDIT_ACTION, MAIN_ACTION, …
• Data: data to operate on, expressed as a URI
• Example: VIEW_ACTION content://contacts/1
• •Intent Filter
Describes what Intents an activity can handle
• Activities publish Intent Filters describing their capabilities/
how they can handle certain Intents and their actions
• Navigating between screens is accomplished by resolving
Intents => system matches Intents and Intent Filters
• Activity calls method startActivity(myIntent)
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Intent Receiver, Service, Content Provider
• Intent Receiver
• phone rings
Used to execute code upon an external event, e.g.
• Usually no UI; may use the NotificationManager
• Service
• Runs indefinitely, no UI, no interaction with user
Application component running in the background
• E.g. media player
•
• Content Provider
•
Used to share data with other applications
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Life Cycle of an Android Application
• Each Android application runs in its own Linux
process
• Process’s lifetime not directly controlled by
application
• Determined by the system, depending on running
applications, their importance, available memory
• Components (Activity, Service, Intent Receiver)
impact the lifetime of the application’s process
• Importance hierarchy for killing processes based on
•
Components running in them
• The state of these components
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Android’s Importance Hierarchy
1. Foreground Process
• Required for current user activities
• E.g. running an Activity at the top of the screen
2. Visible Process
• Activity is visible but not in the foreground (onPause())
• E.g. previous activity displayed behind a foreground dialog
3. Service Process
• Holds a Service, not directly visible (e.g. media player,
network up/download)
4. Background Process
• Holds an Activity that is currently not visible (onStop())
• Can be killed at any time to reclaim memory
5. Empty Process
• Holds no active application components
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Fragen?
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