Android Outlook

1. Android Outlook • Android captures a majority of the smart phone market • It is making significant inroads into the high end iPad tablet market. • Amazon and Barnes and Noble are gaining popularity with the 7” low cost ($100 to $200) tablets. • Androids will be the base OS for a variety of other low cost devices such as wrist watches, head phones, CD/DVD players, smart TVs, and credit card replacements • Android is capable to drive laptop and NetBook computers, though its impact in these areas are limited to date. • According to the text, 850,000 Android devices are activated daily. Note: It is possible to dual boot iOS/Androids on a jail broken iPhone or iPodTouch with OpeniBoot and iDroid software

2. Why Android? • General Advantages • Fully open-source, non-proprietary, operating system supported by the Open Handset Alliance of 80 major manufacturers • No certification process to become an Android developer • No preferences for native applications • Low learning curve for Java developers • Rapid innovations such as: • Android Beam; Near Field Communication (NFC) technology for near device data exchange • Home widgets and live wallpaper • Shared data between applications • Google map integration with Android applications • On board SQL-lite • Background services and applications

4. Application Security • Applications can store data persistently with the following limitations • They can only write to their own data folders • They must request user permission for access to services such as: internet access, audio recording, and near field device interaction, SD card • Inherits low level Linux securities • Applications can create content managers to expose their data to selected other applications

5. Versions Philosophy: Release early and often, with backward compatibility when possible. Active devices run using many of the nineteen Android versions • 2:Gingerbread still used by some android smart phones • 3: Honeycomb (May 2011. Experimental) • Used by the Motorola Xoom • Source code withheld by Google • Intended for larger screen, multi-core tablets, not smart phones • 4: Ice Cream Sandwich (October 2011) • Source code released by Google • Brings honeycomb features to smart phones • Facial recognition, better photography, offline functionality, application folders

7. Mobile Device Hardware • RISC Processors • Low power; ideal for mobile devices • Simple processors (35000 transistors per chip is typical) • ARM • Dominates the mobile technology market • No microcode, Most instructions are single cycle • Conditional execution and switched register banks • MIPS • All instructions are single cycle • Loads data/instruction in one cycle • Eliminates multiply/divide to allow very high clock rates • Register windows speed up subroutine calls, but limits the number of nested calls

8. Developing Android Applications • Java using the Android Software Development Kit (ADK) • Most Android applications are developed with the ADK • Code in Java, then compile into Dalvik executables, which run in a specialized virtual machine optimized for mobile devices • C and C++ using the Native Development Kit (NDK) • Does not significantly improve performance in most cases • Useful for CPU-intensive operations such as signal processing • The Android framework provides two ways to access C/C++ code • The Java Native Interface (JNI) • The NativeActivity class to interact with Services & Content Providers • Google App Inventor • For Novice programmers, who want to create Android applications • Created by Google, maintained by MIT • Apps created by drag-and-dropping visual objects

9. Second Presentation Pick one of the following (or another if approved) • Describe how they work • Create a short demo if possible Possible Selections • Google App Inventor • Native Development Kit • Android features not discussed in class(Examples: Web View, Media Frameworks, OPENGL for 2D/3D Animation, Telephony, Location-based Services, Networks, Using Sensors, Home Screen Widgets and Live wallpaper, NFC, Web View • Manufacturer specific development kits • Google’s stand alone API recently released

10. Mobile Development Considerations • User Priorities: 1.Phone, 2. Text messaging, 3. Camera, 4. MP3 Player, 5. Other useful things like Google Maps, Browsing, Facebook, and applications. • Never interrupt a user activity, instead use the led notification light, vibration, message bar, or ringtones • Always be polite • Applications should be intuitive, easy to use, and conform to standards • Limited battery life: Detect when the battery is not charging and avoid compute-bound operations if this is the case. • Life cycle: Applications do not control when they start or end. Seamlessly respond to applications being paused and restarted

11. Considerations (cont.) • Messaging costs • Let users choose between high accuracy/fast/high cost transmission and low accuracy/slow/low cost messaging • Consider frequency and times of updates and minimize the amount of data transferred • Transfer at off-peak periods • Always respect user preferences • Limited processing power • Code should be as efficient as possible • Make use of background services and worker threads to maximize responsiveness • Save and restore processing states

12. Additional Considerations • Limited persistent storage • Applications should cache data when possible • Manage data stores to remove unneeded data faithfully • Limited memory sizes • Minimize application size • Obfuscate code to minimization footprint and reduce reverse engineering (Pro Guard Java class shrinker) • Intermittent or unreliable connections • Graceful degradation for seamless operation • Revert to limited operation or previously cached data • Varied screens • Different user interfaces other than buttons and text boxes • Detect orientation changes • Accommodate various display resolutions

13. Additional Considerations (cont.) • Consider the users that might use applications • Android devices are sold in hundreds of countries having different languages spoken and different cultures • People with disabilities need font size options or audio interfaces • Be liberal with user preferences • Consider state-of-the-art device features • Utilize device features when they exist

14. Setting up the ADK Step 1:Java (JDK 5 or later) • MAC: Normally comes with Java preloaded • Windows (Only the JDK, not the bundles): • Download: www.oracle.com/technetwork/java/javase/downloads/index.html • Environment Variable, JAVA_HOMEMy Computer, right click, Properties, Advanced, Environment Variables, New, Javva_Home, C:\Program Files\Java\jdk<version> • Linux: • Download: sudo apt-get instal openjdk-7-jdk • Use downloaded version: sudo update-alternatives –config java • Environment variable: Edit .profile file export JAVA_HOME=<path to JDK>

15. Setting up the ADK (cont.) Step 2: Eclipse (Version 3.6 or later) • Download: www.eclipse.org/downloads/ • Distribution is a compressed .zip file • Windows: Extract the zip file into c:\eclipse Note: some versions don’t like spaces in the filenames • MAC: Extract into the Applications folder • Linux: Extract into the home directory • Executing: set a workspace location, which is a folder under your home directory (or on the p: drive) Note: Lab computer will have Eclipse set up along with the Android Emulator. To work with the on-campus system, set your workspace to a folder withinin your p: or travel disk drive.

16. Setting up the ADK (cont.) Step 3: The Android Emulator This step allows us to develop without actually having an android phone or tablet device • Download: http://developer.android.com/sdk • Unpack the distribution compressed zip file • Windows: c:\android-sdk-windows (no spaces) • MAC and Linux: unpack to your home directory • Run the Android SDK Manager(its in the installation folder) • Choose Available packages and install • Include SDK Platform Tools, Documentation • Modify the PATH environment variable • Add Android SDK tools, platforms tools, and Java bin directories Note: On lab computers, this step should already be complete

17. Setting up the ADK (cont.) Step 4: The Android Development Tools This step will be necessary on lab computers • Eclipse -> help -> install new software • Work with field, Type: http://dl-ssl.google.com/android/eclipse/ • Developer tools -> next -> accept license -> finish • Eclipse -> window -> preferences -> Android • SDK location:type the location of the android SDK. Click Apply. • You can bring up the emulator from within Eclipse • Window -> Android SDK and AVD manager

18. Application Structure Created application (Helloharveyd.apk) • An .apk extension (Android package, which is standard compression) • Most compression utilities don’t recognize this extension. • Renaming to .zip enables .apk files to be unzipped. • The Android builder compiles many of the contained files

19. An Android package • AndroidManifest.xml • Lists application activities (user tasks) and services • Lists permissions, and features required by the application • List permissions granted for access by other applications • Lists features used by this application • src: Source Java classes • bin: Compiled Java and Android classes • assets: Arbitrary collection of files and folders • res • Various resource folders to separate data from application code • Multimedia, user interface layouts, xml files, data values abstracted from the application, and raw data • gen: Java files automatically generated during a build

20. Android Build Process

21. The Build Process

22. Loads into memory Activity Life Cycle Note: The DalvikVM controls the Life cycle, not the application