What is Android? Mobile Device Application Development COMPSCI 345

Transcription

1 What is Android? Mobile Device Application Development COMPSCI 345

2 Android is an Operating System An interface between users/applications and the hardware. Provides a high-level view of I/O devices. Provides useful abstractions: processes, memory, files... Resource allocator Mediates conflicting requests for CPU time and access to devices (camera, phone, sensors,...) and other resources. Control program Provides environment for safe execution of user applications. Prevents processes from reading memory outside their address space or accessing devices without permission.

3 Android is an Operating System Built on top of Linux (kernel version ). Linux (written in C) handles: thread management. memory management. power management. Android is not (?) a Linux distribution. The kernel was modified for mobile devices. Optimized for minimal memory footprint. Does not include many standard tools and libraries.

4 Why Linux? Hardware manufacturers can develop device drivers for a well-known kernel. Security: A mature open-source kernel in widespread use. Trusted by corporations and security experts. Constantly being researched, attacked, and fixed. Application sandbox: Every app runs as a separate Linux process. Actually, all software above the kernel is sandboxed.

5 Not Just an Operating System Android is an open source, Linux-based software stack created for a wide array of devices and form factors. A software stack is a set of software subsystems that comprise a platform for the execution of applications. Devices: smartphones, tablets, wearables,... A form factor prescribes the size, shape, and other physical characteristics of devices. Mobile phone form factors: bar, flip, slider.

6 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Hardware Abstraction Layer Linux Kernel

7 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Hardware Abstraction Layer Linux Kernel Thread management Memory management Power management Drivers usb wifi audio camera display keypad bluetooth binder (IPC) shared memory

8 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Hardware Abstraction Layer Provides standard interfaces exposing device capabilities to Java API framework. Audio Sensors Camera Bluetooth Linux Kernel

9 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Hardware Abstraction Layer Linux Kernel Many core system components run native code requiring libraries written in C or C++. Java API Framework exposes some of these libraries to apps. Libc Webkit Open GL ES OpenMAX AL Media Framework

10 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Designed to run multiple VMs on low-memory devices. Runtime libraries that implement most of the core Java API. Hardware Abstraction Layer Linux Kernel

11 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Hardware Abstraction Layer Linux Kernel The building blocks used by app developers. Java classes for: UI components UI layouts Activities Resources Notifications Content providers

12 Android is a Software Stack System Apps Android API Native C/C++ Libraries Android Runtime Hardware Abstraction Layer Stored in the read-only /system/app folder. Web browser Calendar Camera Dialer Linux Kernel

13 Dalvik Virtual Machine VM for executing Android apps. Optimized for running multiple instances. Register-based. Fewer (but more complex) instructions compared with stack-based VMs (like the JVM). Android Runtime App A App B App C App D Dalvik VM Dalvik VM Dalvik VM Dalvik VM Hardware Abstraction Layer Linux Kernel

14 Dalvik Virtual Machine Source Code Java Compiler Byte Code JVM

15 Dalvik Virtual Machine Source Code Java Compiler Byte Code JVM DEX Compiler Dalvik Byte Code Dalvik VM

16 Android Runtime (ART) Successor of Dalvik for improved performance. AOT compiler. Improved garbage collection. More debugging features. Runs DEX bytecode for backward compatibility. History: Included in 4.4 (KitKat) as alternative runtime. Replaced Dalvik entirely in 5.0 (Lollipop). Added JIT compiler with code profiling in 7.0 (Nougat).

17 Android Development In order to write apps, you will need: JDK (SE) 7 or 8 The Android SDK Android Studio Apps can be run in the SDK s emulator or deployed directly to an attached device. Some knowledge of XML is needed. app configuration resource management

18 Using Java All features of Java 7 are supported. Supported features of Java 8: lambda expressions method references type annotations repeatable annotations (API 24 only) default and static interface methods (API 24 only) Google vs. Oracle: can an API be copyrighted?

19 Other Development Languages Kotlin is now an official Android language. Resembles but improves upon Java (safer, more concise) Designed to interoperate with Java. Can use the Java Class Library. Runs on the JVM. Can be compiled to JavaScript source code. Created and developed by JetBrains. Fully supported in Android Studio.

20 Android SDK Developer tools compiler debugger emulator Documentation Sample code and tutorials Implementation of the Android API

21 Android Studio Google s official IDE for Android development Built on top of IntelliJ IDEA (Community Edition) World-class code editing, debugging, performance tooling, a flexible build system, and an instant build/deploy system all allow you to focus on building unique and high quality apps.

22 Material Design A design philosophy for the look-and-feel of an app that allows for a unified experience across platforms and device sizes. Three guiding principles: Material is the metaphor. Bold, graphic, intentional. Motion provides meaning.

23 Material is the Metaphor Inspired by paper and ink. Grounded in tactile reality. Surfaces and edges provide visual cues. Familiar tactile attributes suggest affordances. Flexibility of material creates new affordances that supersede laws of physics without breaking them. Realistic lighting shows seams, divides space, and indicates moving parts.

24 Bold, Graphic, Intentional Elements of print-based design create hierarchy, meaning, and focus. typography space scale color Immerses user in the experience. Emphasis on user actions makes core functionality immediately apparent and provides waypoints.

25 Motion Provides Meaning Primary user actions are inflection points that initiate motion, transforming the whole design. Objects presented without breaking continuity of experience, even as they transform and reorganize. Motion focuses attention and maintains continuity. Transitions efficient yet coherent.

26 History 2001 Google starts filing for mobile patents Google purchases Android, Inc Open Handset Alliance 2008 Android Android Sued by Oracle for copyright/patent infringement Acquires Motorola and 17,000 patents. Purchases 1023 patents from IBM.

27 History Version Android 1.0 API Level 1 Release Date 09/23/2008 Web Browser WiFi and Bluetooth Camera Media Player Instant messaging Google sync: Gmail, Contacts, Calendar Standard apps alarm clock, dialer, launcher, gallery, calculator, settings App downloads and updates through Android Market Text messaging Google Maps with Street View

28 History Version Android 1.1 API Level 2 Release Date 02/09/2009 Map improvements Save attachments Show/hide dial pad

29 Cupcake Version Android 1.5 API Level 3 Release Date 04/27/2009 Widgets Video recording/playback Animated screen transitions Auto-rotation option Pictures in contacts Upload to YouTube and Picassa Virtual keyboards with text prediction and user dictionary

30 Donut Version Android 1.6 API Level 4 Release Date 09/15/2009 Text-to-speech engine Expanded gesture framework Multilingual speech synthesis Integrated camera/gallery Select multiple photos for deletion Enhanced voice and text entry search View app screenshots in Android Market

31 Eclair Version Android 2.0 API Level 5 Release Date 10/26/2009 Version Android API Level 6 Release Date 12/03/2009 Version Android 2.1 API Level 7 Release Date 01/12/2010 Live wallpapers Multi-touch events Improved Google Maps Tap contact photo to call Many new camera features Add multiple accounts to a device for synchronization of and contacts Improved typing speed on virtual keyboard with smarter dictionary that uses contact names as suggestions.

32 Froyo Version Android 2.2 API Level 8 Release Date 05/20/2010 USB tethering Adobe Flash support WiFi hotspot functionality Support for high PPI displays File uploads in browser app JavaScript V8 engine in Chrome Numeric and alphanumeric passwords Android Cloud to Device Messaging (C2DM) support

33 Gingerbread Version Android 2.3 API Level 9 Release Date 12/06/2010 Version Android API Level 10 Release Date 02/09/2011 Support for extra-large screens Last version to target only phones Oldest version still used in the wild Multiple cameras Native support for VoIP NFC support, allowing user to read an NFC tag embedded in poster, sticker, advertisement. Native support for new sensors (gyroscope, barometer,...)

34 Honeycomb Version Android 3.0 API Level 11 Release Date 02/22/2011 Version Android 3.1 API Level 12 Release Date 05/10/2011 Version Android 3.2 API Level 13 Release Date 07/15/2011 Optimized for tablets Holographic UI Fragments API Action bar System bar USB On-The-Go Encrypt user data External keyboards

35 Ice Cream Sandwich Version Android 4.0 API Level 14 Release Date 10/18/2011 Version Android API Level 15 Release Date 12/16/2011 Photo editor Face Unlock Customizable launcher Unified SDK for both tablets and phones Improved voice integration Improved Holographic UI with Roboto font family Improved camera app with zero shutter lag, time lapse settings, panorama mode, ability to zoom while recording

36 Jelly Bean Version Android 4.1 API Level 16 Release Date 07/09/2012 Version Android 4.2 API Level 17 Release Date 11/13/2012 Version Android 4.3 API Level 18 Release Date 07/24/2013 Smoother UI Multichannel audio Camera improvements Expandable notifications Lock screen improvements Multi-user support on tablets RTL languages supported Open GL ES 3.0 support

37 KitKat Version Android 4.4 API Level 19 Release Date 10/31/2013 Version Android 4.4W API Level 20 Release Date 06/25/2014 Wearable extensions NFC host card emulation, enabling device to replace smart cards Storage Access Framework UI updates for Google Maps Wireless printing Android Runtime (experimental) New framework for UI transitions

38 Lollipop Version Android 5.0 API Level 21 Release Date 11/12/2014 Version Android 5.1 API Level 22 Release Date 03/09/2015 Support for 64-bit CPUs ART Tap and Go Project Volta Flashlight app Material Design Open GL ES 3.1 on supported GPU configurations 15 new languages: Basque, Bengali, Burmese, Chinese (Hong Kong), Icelandic, Kannada, Kyrgyz, Macedonian, Malayalam, Marathi, Nepali, Sinhala, Tamil, and Telugu

39 Marshmallow Version Android 6.0 API Level 23 Release Date 10/05/2015 Doze mode Native fingerprint reader support MIDI support for musical instruments App permissions now granted at runtime Automatic full backup and restore for apps Contextual support from keywords within apps

40 Nougat Version Android 7.0 API Level 24 Release Date 08/22/2016 Version Android 7.1 API Level 25 Release Date 10/04/2016 Daydream virtual reality platform Ability to screen zoom Multi-window support Vulcan 3D rendering API Unicode 9.0 emoji support Picture-in-picture support for Android TV New JIT compiler with code profiling to ART Another system partition for seamless system updates

41 Oreo Version Android 8.0 API Level 26 Release Date 03/21/2017 Version Android 8.1 API Level 27 Release Date 12/5/2017 Neural networks API Redesigned architecture makes it easier and faster for hardware makers to deliver Android updates. Adaptive icons Multi-display support Shared memory API Faster boot time Notification improvements

42 Pie Version Android 9.0 API Level 26 Release Date 08/06/2018 New UI for quick settings menu. Screenshot button added to power options. New gesture-based navigation options. Android Dashboard Tells how much time user spends on device and with particular apps. Allows user to set time limits on apps.

43 Usage (October 2018) Version Share Oreo 22% Nougat 28% Marshmallow 21% Lollipop 18% KitKat 8% Jelly Bean 3%

44 Popularity 1,000,000 new users every day (2017) 1,000,000,000 active users daily (2017) 2,000,000,000 active users monthly (2017) 85% of global smartphone market share (2018) Largest installed base of any mobile platform