Programim Mobile Leksion Tema: Programimi Mobile në Java
Në këtë leksion. . Familja Java dhe J 2 ME n Konfigurimet CLDC dhe CDC, Paketat Opsionale n Krijimi i aplikacioneve MIDP dhe CDC n Shembuj aplikacionesh n
Hyrje në familjen Java n n J 2 EE kryesisht shërben për ndërtimin e aplikacioneve enterprise që e vënë theksin në zhvillimin e aplikacioneve server-side dhe për web. J 2 SE është e destinuar për ndërtimin e aplikacioneve konvencionalë për kompjuterat desktop. J 2 ME është nëngrup i J 2 SE që shërben për zhvillimin e programeve për pajisjet e ndërfutura që nuk mund të suportojnë implementim të plotë të J 2 SE. Java Card ofron një mjedis për zhvillimin e aplikacioneve që ekzekutohen në karta smart.
Për shembull do të ishte jo efiçente që në një makinë desktop të përdorej J 2 EE e cila përfshin paketa për aplikacione enterprise. Gjithashtu implementimi i plotë i J 2 SE nuk mund të suportohet nga pajisjet e vogla që kanë më pak burime se një makinë desktop.
Platforma J 2 ME n n n J 2 ME është pjesë e familjes Java e ndërtuar me qëllim që të shërbejë për ndërtimin e aplikacioneve që ekzekutohen në mjedise që punojnë me bateri dhe jo me energji elektrike. Pajisjet me aftësi të ngjashme grupohen në konfigurime dhe brenda secilit konfigurim krijohen profile për të klasifikuar më tej llojin e pajisjes. J 2 ME nuk është gjuhë e re por është një version i përshtatur i Java për pajisjet e vogla duke hequr nga J 2 SE ato pjesë që nuk mund të suportohen. Megjithatë platforma J 2 ME mund të ekzekutohet në një larmi pajisjesh si TV, PDA, libra elektronikë, telefona etj.
Për momentin në platformën J 2 ME ekzistojnë dy konfigurime: n CLDC(Connected Limited Device Configuration), për pajisje me ¨ ¨ ¨ Ndërfaqe përdoruesi shumë të thjeshtë Kujtesë të vogël (160 Kb deri në 512 Kb) Komunikim wireless Procesor 16 ose 32 bit Energji e kufizuar, zakonisht me bateri Shembuj: telefonat celularë, librat elektronikë, PDA të thjeshta etj. Këtyre pajisjeve do i referohemi si pajisje më pak të afta.
CDC(Connected Device Configuration), për pajisje me ¨ Ndërfaqe përdoruesi më të larmishme ¨ Kujtesë nga 2 – 16 M. ¨ Lidhje me disa tipe rrjetash. ¨ Procesorë 16 ose 32 bit. ¨ Shembuj: Tv, PDA etj. n Këtyre pajisjeve do i referohemi si pajisje më shumë të afta.
Pajisjet më pak të afta: Konfigurimi CLDC n n Për momentin ekzistojnë dy versione CLDC: CLDC 1. 0 i cili është lëshimi i parë i specifikimit CLDC 1. 1 i cili është version i përmirësuar i 1. 0. CLDC ofron një mjedis ekzekutimi Java (JRE) bazë, por grupi i klasave bazë zakonisht është i vogël dhe ka nevojë që të përmirësohet nga klasa shtesë. Në fakt CLDC nuk ka ndonjë API të integruar për menaxhimin e ndërfaqes me përdoruesin, nuk implementon ndonjë model I/O dhe ka mangësi në arritjen e sigurisë.
MIDP (Mobile Information Device Profile) n n n Profili MIDP i shtohet konfigurimit CLDC për të mbushur funksionalitetet që mungojnë. MIDP në fakt është një grup API-sh dhe librarish që ofrojnë funksionalitete si ndërfaqe përdoruesi, lidhje në rrjet, ruajtje të dhënash etj. Aktualisht ekzistojnë dy versione MIDP të cilët implementohen në pajisje reale: MIDP 1. 0 është lëshimi i parë i profilit dhe përfshin ndërfaqe përdoruesi (nivel jo i avancuar) e siguri në rrjet. MIDP 2. 0 ka përshtatshmëri kthimi me MIDP 1. 0 dhe ka funksione shtesë si ndërfaqe më të avancuar. Multimedia, lojëra etj.
n n Aktualisht është specifikuar edhe gjenerata e tretë e MIDP me emrin JSR 271. Ky specifikim bazohet në MIDP 2. 0 dhe ka përshtatshmëri kthimi me të. Një aplikacion që zhvillohet sipas profilit MIDP quhet MIDlet. Këto lloj aplikacionesh nuk përdorin një metodë statike main për pikë hyrëse sikurse ndodh në aplikacionet tradicionalë desktop. Pika hyrëse e një aplikacioni MIDlet është një klasë që trashëgon nga java. microedition. midlet. MIDlet. Klasa MIDlet ka të përcaktuara disa metoda abstrakte që thirren kur gjendja e MIDlet-it ndryshon.
Metoda Përshkrimi start. App() Thirret nga AMS kur MIDlet fillon të ekzekutohet nga e para ose kur rimëkëmbet nga një gjendje e pezulluar. destroy. App() Thirret nga AMS kur MIDlet përfundon. pause. App() Thirret nga AMS kur MIDlet pezullohet notify. Destroyed() Thirret nga MIDlet. I kërkon AMS që ta shkatërrojë vetë MIDlet-in. notify. Paused() Thirret nga MIDlet. I kërkon AMS që ta pezullojë vetë MIDlet-in. resume. Request() Thirret nga MIDlet-i i pezulluar(p. sh nga një thred në background). I tregon AMS se MIDlet-i do të dalë nga gjendja e pezulluar dhe të bëhet sërish aktiv. Tabelë 1 - Metodat e ciklit jetësor të MIDlet Një ose më shumë MIDlet-e së bashku me të gjithë skedarët dhe klasat e tjera që i duhen aplikacionit paketohen në një suitë MIDlet. Një suitë MIDlet përbëhet nga një skedar JAR dhe një skedar JAD. Skedari JAR është skedari që duhet të dërgohet në telefon për të instaluar aplikacionin. CDC është plotësisht i përshtatshëm me CLDC.
Suporti për rrjetat n J 2 ME ofron ndërfaqe rrjeti për zhvillimin e aplikacioneve wireless dhe shfrytëzon aftësitë e këtyre pajisjeve për tu lidhur në rrjet sipas teknologjive të ndryshme të rrjetit wireless. Suporti për lidhjen e pajisjeve në rrjet kryhet nga GCF hierarkia e së cilës tregohet në Figurë
n Qëllimi kryesor i GCF është që të përcaktojë një arkitekturë rrjeti sa më të përgjithshme dhe të lejojë akses për tiparet që lidhen me protokollet. GCF i ofron përdoruesit një grup të vetëm abstragimesh për të menaxhuar disa protokolle. GCF përdoret edhe nga CLDC edhe nga CDC por ka disa ndryshime në protokollet që suportojnë. Disa nga llojet e lidhjeve që mund të krijohen janë Http. Connection, UDPDatagram. Connection, Sip. Connection.
n n Protocol: Protokolli që do të përdoret për lidhjen. Protokolli përdoret nga GCF për të gjetur klasën e saktë që do të përdoret. Address: Adresa në rrjet e pikës fundore të lidhjes. Klasat Connection që suportojnë funksionalitete server të lejojnë të specifikosh vetëm portën e lidhjes, p. sh socket: //: 80 krijon një lidhje socket në server në portën 80 të localhost. Parameters: Në lidhje mund të përcaktohen në mënyrë opsionale disa parametra ekstra. P. sh lidhja Sip. Connection të lejon të shtosh parametra transporti. Parametrat gjithmonë specifikohen si listë me çifte name = value të cilët ndahen nga njëri-tjetri me pikëpresje. P. sh: Sip. Connection sc = ( Sip. Connection )Connector. open (“sip: +475551234567; postd = pp 22@foo. com; user=phone“);
Teknologjia e standardizimit në Java n n E gjithë teknologjia Java kalon përmes procesit JCP (Java Community Process. Procesi mbikëqyret nga EC(Executive Committee). Ekzistojnë dy komitete ekzekutive: një për J 2 SE dhe J 2 EE, dhe një për J 2 ME. Është detyrë e EC që të mbledhë, zhvillojë dhe të aprovojë JSR(Java Specification Request). Rezultati i këtij procesi përbëhet nga tre artefakte: Specifikimi: Është API përfundimtare, përmban klasat dhe manualin që i shpjegon përdoruesit se si ta përdorë këtë teknologji. TCK(Test Compatibility Kit): Përfshin testet që duhet të kalojë një specifikimin. RI(Reference Implementation): Është implementim i specifikimit i cili i lejon përdoruesit që të fillojnë të punojnë me të.
Mobile Service Architecture n MSA u finalizua në Dhjetor 2006 si zhvillim i JTWI. Në këtë specifikim janë shtuar shumë më tepër paketa opsionale, siç tregohet në Figurën 6. Përveç MSA dhe MSA Subset ekziston gjithashtu MSA Advanced Specifikation. Si konfigurim për MSA mund të përdoret edhe CDC. Pajisjet mobile mund të suportojnë të gjithë MSA ose vetëm një pjesë të teknologjive të përfshira në të.
Mjedisi zhvillues n n n Për të programuar në Net. Beans me J 2 ME është e nevojshme që paraprakisht në kompjuter të jenë të instaluar: Java SE Development Kit (JDK) 5. 0. 6 e tutje. Net. Beans IDE Net. Beans Mobility Pack për CLDC dhe/ose CDC. Paketat duhet të instalohen sipas radhës së mësipërme. Gjithashtu ekziston një opsion për shkarkimin e Net. Beans IDE së bashku me JDK-në.
Shtimi i një librarie të re në Netbeans
Mobile information devices n n 20 most people probably think of portable devices as intelligent phones or personal digital assistants (PDAs), the distinction is arbitrary. For the purposes of this course we will use the term MID to include any handheld device which has some form of micro-processor in it and which can have new applications loaded onto it. Lecture 1 Introduction Programming Handheld and Mobile devices
Shembull: Krijimi i një aplikacioni MIDlet
Dy hapat e tjerë kanë të bëjnë me konffigurimin e pajisjes emulator për sa i përket tipit dhe pam jes së saj. Më pas paketën <default package> të projektit mund të shtohen MIDlet-e. Më poshtë tregohet kodi burim i një MIDlet-i të thjeshtë dhe pamja se si duket në emulator. import javax. microedition. lcdui. *; import javax. microedition. midlet. *; public class Hello. World extends MIDlet { Display display ; Form form ; public void start. App() { display = Display. get. Display(this); form = new Form("Helloworld example"); form. append("Hello World!"); display. set. Current(form); } public void pause. App() {} public void destroy. App(boolean unconditional) { notify. Destroyed( ); }}
Hedhja e MIDlet-it në telefon n Pasi projekti kompilohet, Net. Beans krijon Suitën MIDlet për projektin e cila gjendet në folderin Hello. World/dist. Në polder gjenden dy skedarë Hello. World. jad dhe Helloworld. jar. Skedari i dytë është arkivi që ka të gjithë skedarët që i duhen aplikacionit që të punojë. Rrjedhimisht për të instaluar MIDlet-in në telefon ky arkiv duhet të transferohet fillimisht në telefon. Në disa raste të veçantë duhet të transferohet edhe skedari. jad. Pasi dërgohet skedari në telefon, fillohet instalimi duke hapur këtë skedar.
Mobile information devices n n The emergence of genuinely portable devices which contain sufficient computing power to support a range of applications, many of which were originally developed for conventional personal computers, is one of the major changes in the world of technology in recent years. It has accompanied the emergence of very widespread adoption of mobile phones and these technologies are now merging, creating mobile information devices (MIDs) with the ability to connect with each other and with conventional computer networks 25
Operating environments Palm OS n J 2 ME n Other Java environments n. Net Compact n Symbian n Linux n 26
Languages n n n 27 C/C++ ¨ Palm OS ¨ Symbian ¨. NET ¨ Linux Java ¨ J 2 ME ¨ Other Java environments C# ¨. NET n n n Visual Basic ¨. NET Python scripting ¨ Some mobile phones Mobile scripting languages ¨ Many mobile phones Lecture 1 Introduction Programming Handheld and Mobile devices
Issues to bear in mind n Screen Size ¨ Most Palm Powered handheld screens are only 160 x 160 pixels, so the amount of information you can display at one time is limited. n Quick Turnaround Expected ¨ On a PC, users don’t mind waiting a few 28 seconds while an application loads because they plan to use the application for an Programming Handheld extended amount of time. By contrast, the devices and Mobile Lecture 1 Introduction
More issues to bear in mind n n 29 PC Connectivity ¨ PC connectivity is an integral component of the Palm Powered handheld. The handheld comes with a cradle that connects to a desktop PC and with software for the PC that provides “one button” backup and synchronization of all data on the handheld with the user’s PC. Input Methods ¨ Most users of Palm Powered handhelds don’t have a keyboard or mouse. Users enter data into the handheld using a pen. They can either write characters in the input area or use the keyboard dialog provided on the handheld. Lecture 1 Introduction Programming Handheld and Mobile devices
More issues to bear in mind n Power ¨ Handhelds run on batteries and thus do not have the same processing power as a desktop PC. The handheld is intended as a satellite viewer for corresponding desktop applications. If your application needs to perform a computationally intensive task, you should implement that task in the desktop application instead of the handheld application. n Memory ¨ Palm Powered handhelds have limited heap space and storage space. Different versions of the handheld have between 512 K and 8 MB total of dynamic memory and storage available. The handheld does not have a disk drive or PCMCIA support. 30 Lecture 1 Introduction Programming Handheld and Mobile devices
More issues to bear in mind n File System ¨ Because of the limited storage space, and to make synchronization with the desktop computer more efficient, Palm OS does not use a traditional file system. You store data in memory chunks called records, which are grouped into databases. n Backward Compatibility ¨ Different versions of Palm Powered handhelds 31 are available, and each runs a different Programming Handheld version of Palm OS. Users are not expected and Mobile devices Lecture 1 Introduction
APPROACHES TO MOBILE DEVELOPMENT NATIVE, WEB OR HYBRID?
NATIVE APPS n n Binary executable files on the device. Can access all API’s made available by OS vendor. SDK’s are platform-specific. Each mobile OS comes with its own unique tools and GUI toolkit. Different tools, languages and distribution channels associated with leading mobile operating systems * IBM, Native, web or hybrid mobile app development, 2012. IBM Software Thought Leadership White Paper
NATIVE APPS PROS Easy low-level hardware access services. Easy access to high level services important to personal mobile experience. Full use of all functionalities that modern mobile devices have to offer. CONS Code Reusability : Low Development & maintenance: Timeconsuming & expensive. Designers are required to be familiar with different UI components of each OS. Upgrade flexibility: Low. High usability.
APPROACHES TO CROSS PLATFORM MOBILE DEVELOPMENT
CROSS-COMPILATION Separates build environment from target environment. n Platform-independent API using a mainstream programming language like Java. Script, Ruby or Java. n The cross-compiler then transforms the code into platform-specific native apps. n The software artifact generated can be deployed and executed natively on the device. ADVANTAGES: n Improved performance and User Experience. n Full access to functionalities of underlying mobile OS and device specific capabilities. DISADVANTAGES: n Highly complex as cross-compilers are difficult to program. n Need to be kept consistent with fragmented mobile platforms and operating systems available. n
VIRTUAL MACHINE APPROACH A virtual machine is used to abstract the target platform details from the application’s running code. n The framework provides both the API and runtime environment. n The runtime executes on the mobile device and enables interoperability between the device’s OS and the mobile application. ADVANTAGES: n Improved performance and User Experience. n Full access to functionalities of underlying mobile OS and device specific capabilities. n Portability: VM’s are easier to maintain & more flexible to extend. DISADVANTAGES: n Slower due to runtime interpretation latency. n
MOBILE WEB APPS Use standard web technologies such as HTML 5, CSS 3 & Java. Script. n Features of HTML 5 - Advanced UI components, access to rich media types, geolocation services & offline availability. n Increasing popularity of HTML 5 in rendering engines such as Web. Kit. n Runs on a standalone mobile web browser. n Installed shortcut, launched like a native app. n UI logic resides locally; makes the app responsive and accessible offline. ADVANTAGES: n Multiplatform support. n Low development cost. n Leverage existing knowledge. DISADVANTAGES: n Limited access to OS API’s. n
HYBRID APPS Combines native development with web technology. n The web app runs inside a thin wrapper native app. n The wrapper native app uses the OS API’s to create an embedded HTML rendering engine which provides a bridge between the browser and device API’s. n The communication between web app and native app normally happens over Java. Script via custom built API’s. ADVANTAGES: n Flexibility of web apps combined with feature richness of native apps. n Simplified deployment and immediate availability. n Leverage existing knowledge. DISADVANTAGES: n Poorer user experience as compared to native apps. n Access to advanced device capabilities normally restricted. n
CROSS-PLATFORM FRAMEWORKS CONS PROS Code Reusability Plugins Easy for web developers Might not support every feature of OS Cannot use own tools/IDE Slower. Reduced development costs Support for enterprise & cloud services Easy Deployment High end graphics & 3 D support limited Vendor lock-in
CROSS-PLATFORM FRAMEWORKS * http: //setandbma. files. wordpress. com/2011/12/wora-platforms. png
Rho. Elements – Rho. Mobile Suite From Motorola Solutions TECHNICAL ARCHITECTURE: Cross compilation using Virtual Machine. n Single source codebase written in Ruby and UI constructed using HTML 5, CSS 3, Java. Script running on Ruby interpreter on the device. n Support for SQLite enables the local storage of relational data, enabling offline capabilities for both hybrid and native HTML 5 applications. DESIGN PATTERNS: n Model-View-Controller pattern for maintainability and best practices. n Object Relational Mapper design for easy data manipulation. SUPPORTED PLATFORMS: n WM /WEHH , Win. CE 5. 0+, Android 2. 1+, i. OS 3. 0+, BB 4. 6+, WP 7 n
Rho. Elements – Rho. Mobile Suite By Motorola Solutions *http: //leckylao. files. wordpress. com/2010/06/screen-shot-2010 -06 -12 -at-3 -28 -30 pm. png
Rho. Elements – Rho. Mobile Suite From FEATURES: HTML 5 Motorola Solutions App Caching, Web. Sockets, Web. Workers, Local & Session Storage, SQLite, Semantic Elements, Form Attributes IDE USED: n Rho. Studio – An Eclipse based IDE STRENGTHS: n Design patterns used. n Applications look and behave identically on all devices. WEAKNESSES: n Updating HTML/Java. Script code needs a complete rebuild. n Need to know Ruby well, which is not as popular as other programming languages. n Doesn’t generate source code, only native package which can restrict any further tweaking of the app. n
Rho. Elements – Rho. Mobile Suite From Motorola Solutions SCORE (OUT OF 3) * http: //floatlearning. com/2011/07/which-cross-platform-framework-is-right-for-me/
PHONEGAP From Nitobi now acquired by Adobe TECHNICAL ARCHITECTURE: n Web approach using hybrid model. n Single source codebase written HTML 5, CSS 3, Java. Script running on a mobile browser embedded in a native app wrapper. n Device capabilities accessed through device-independent Java. Script API. SUPPORTED PLATFORMS: n i. OS, Android, Blackberry, WP 7, Symbian, Palm, Samsung Bada IDE USED: n MAC OS X & XCODE for i. Phone & i. Pad. n Google Android SDK, Eclipse ADT Plugin, Ant as well as Eclipse IDE for Android.
PHONEGAP From Nitobi now acquired by Adobe ARCHITECT URE: * http: //arnab. ch/images/phonegap-architecture. jpg
PHONEGAP From Nitobi now acquired by Adobe STRENGTHS: n Native wrapper source code is provided so it can be customized further. n Simple ‘drop-in libraries’ concept makes it easier to develop. n Lowers barriers of adoption for web developers. WEAKNESSES: n Lack of support for native UI components, design patterns & development tools. n The capabilities offered by the framework is limited to what a “Web. View” can do. n Different projects for different platforms n Different Java. Script files on each platform for Phone. Gap itself and plugins n No native UI support n Java, Objective-C or C# requirement to create new plugins n No built-in support for push notifications
PHONEGAP From Nitobi now acquired by Adobe SCORE (OUT OF 3) * http: //floatlearning. com/2011/07/which-cross-platform-framework-is-right-for-me/
TITANIUM From Appcelerator Inc. TECHNICAL ARCHITECTURE: Cross compilation technique – Pre-compilation, front-end compilation, platform & package compilation. n Single source codebase written in Java. Script, compiled into native code and packaged for different target platforms. n Does not use browser engine to render user interface on mobile devices. n Instead the UI elements are converted to true native UI elements when deployed to the phone. SUPPORTED PLATFORMS: n i. OS, Android, Windows & Blackberry IDE USED: n Studio, an Eclipse-based IDE n
TITANIUM From Appcelerator Inc. * http: //www. linux-mag. com/s/i/articles/7719/architecture 1. png
TITANIUM From Appcelerator Inc. STRENGTHS: n n n Native code output very quick and fluid on the phone. Easy setup and startup for developers. Excellent documentation & examples. Strong community forum to find out answers. Intuitive app management environment. Support for desktop and tablet development WEAKNESSES: n Potentially restrictive API’s n Tries to solve too many problems in one shot supporting phones, tablets & desktops.
TITANIUM From Appcelerator Inc. SCORE (OUT OF 3) * http: //floatlearning. com/2011/07/which-cross-platform-framework-is-right-for-me/
Mo. Sync From Mo. Sync AB TECHNICAL ARCHITECTURE: n Cross compilation using Virtual Machine. n Single source codebase written in C/C++ or HTML/Java. Script or a combination of both. n C++ source code platform-independent intermediate code application package SUPPORTED PLATFORMS: n i. OS, Android, Windows Mobile, Moblin/Mee. Go, Symbian & Blackberry IDE USED: n Mo. Sync IDE based on Eclipse.
Mo. Sync From Mo. Sync AB http: //www. straightforward. se/storyserver/sites/straightforward. se. storyserver/files/im ages/Mo. Sync. App. Architecture. preview. png
Mo. Sync From Mo. Sync AB STRENGTHS: Only one project structure for all the platforms. n The same Java. Script file. n Extend Java. Script functionality using C++ or Java and Objective-C n Native UI support n Built-in support for push notifications n Target group: Both web developers looking to enter the mobile space, as well as the ordinary PC/Mac desktop developer with knowledge of C/C++. WEAKNESSES: n No support for accelerometer or camera in most phones. n Contains XML parsing libraries but lacking support for JSON or other data formats. n Doesn’t provide support for MVC; requires little extra effort to create views for data. n
Mo. Sync From Mo. Sync AB SCORE (OUT OF 3) * http: //floatlearning. com/2011/07/which-cross-platform-framework-is-right-for-me/
COMPARISON OVERVIEW Below is a summary of each platform and whether it offers adequate support for a given area. (Scored 2 or better in that criteria) * http: //floatlearning. com/2011/07/which-cross-platform-framework-is-right-for-me/
Tools Phone n Eclipse ( http: //www. eclipse. org/downloads/ ) n ¨ Android Plugin (ADT) n Android SDK ( http: //developer. android. com/sdk/index. html ) ¨ Install everything except Additional SDK Platforms, unless you want to n Windows Users: may need to install Motorola Driver directly ( http: //www. motorola. com/Support/US-EN/Support-
Android SDK Once installed open the SDK Manager n Install the desired packages n Create an Android Virtual Device (AVD) n
SDK Manager
AVD
ADT Plugin (1) n n n In Eclipse, go to Help -> Install New Software Click ‘Add’ in top right Enter: Name: ADT Plugin ¨ Location: https: //dl-ssl. google. com/android/eclipse/ ¨ n n Click OK, then select ‘Developer Tools’, click Next Click Next and then Finish Afterwards, restart Eclipse Specify SDK location (next 3 slides) ¨ Must do this every time start a new project in a new location (at least in Windows)
ADT Plugin (2)
ADT Plugin (3)
ADT Plugin (4)
Creating a Project (1)
Creating a Project (2) Need the items circled Then click Finish
Project Components src – your source code n gen – auto-generated code (usually just R. java) n Included libraries n Resources n ¨ Drawables (like. png images) ¨ Layouts ¨ Values (like strings) n Manifest file
XML n Used to define some of the resources ¨ Layouts (UI) ¨ Strings Manifest file n Shouldn’t usually have to edit it directly, Eclipse can do that for you n Preferred way of creating UIs n ¨ Separates the description of the layout from any actual code that controls it ¨ Can easily take a UI from one platform to
R Class Auto-generated: you shouldn’t edit it n Contains IDs of the project resources n Enforces good software engineering n Use find. View. By. Id and Resources object to get access to the resources n ¨ Ex. Button b = (Button)find. View. By. Id(R. id. button 1) ¨ Ex. get. Resources(). get. String(R. string. hello));
Layouts (1) n Eclipse has a great UI creator ¨ Generates the XML for you Composed of View objects n Can be specified for portrait and landscape mode n ¨ Use same file name, so can make completely different UIs for the orientations without modifying any code
Layouts (2)
Layouts (3) n n Click ‘Create’ to make layout modifications When in portrait mode can select ‘Portrait’ to make a res sub folder for portrait layouts Likewise for Landscape layouts while in landscape mode ¨ Will create folders titled ‘layout-port’ and ‘layout-land’ ¨ n Note: these ‘port’ and ‘land’ folders are examples of ‘alternate layouts’, see here for more info ¨ n http: //developer. android. com/guide/topics/resources/providing-resources. html Avoid errors by making sure components have the same id in both orientations, and that you’ve tested each orientation thoroughly
Layouts (4)
Strings n In res/values ¨ strings. xml Application wide available strings n Promotes good software engineering n UI components made in the UI editor should have text defined in strings. xml n n Strings are just one kind of ‘Value’ there are many others
Manifest File (1) n n Contains characteristics about your application When have more than one Activity in app, NEED to specify it in manifest file Go to graphical view of the manifest file ¨ Add an Activity in the bottom right ¨ Browse for the name of the activity ¨ n n Need to specify Services and other components too Also important to define permissions and external libraries, like Google Maps API
Manifest File (2) – Adding an Activity
Android Programming Components n Activity ¨ n http: //developer. android. com/guide/topics/fundamentals/activities. html Service ¨ http: //developer. android. com/guide/topics/fundamentals/services. html Content Providers n Broadcast Receivers n n Android in a nutshell: ¨ http: //developer. android. com/guide/topics/fundamentals. html
Activities (1) The basis of android applications n A single Activity defines a single viewable screen n ¨ the actions, not the layout Can have multiple per application n Each is a separate entity n They have a structured life cycle n ¨ Different events in their life happen either via the user touching buttons or programmatically
Activities (2)
Services (1) n Run in the background ¨ Can continue even if Activity that started it dies ¨ Should be used if something needs to be done while the user is not interacting with application n ¨ n n n Otherwise, a thread is probably more applicable Should create a new thread in the service to do work in, since the service runs in the main thread Can be bound to an application ¨ In which case will terminate when all applications bound to it unbind ¨ Allows multiple applications to communicate with it via a common interface Needs to be declared in manifest file Like Activities, has a structured life cycle
Services (2)
Running in Eclipse (1) Similar to launching a regular Java app, use the launch configurations n Specify an Android Application and create a new one n Specify activity to be run n Can select a manual option, so each time program is run, you are asked whether you want to use the actual phone or the emulator n ¨ Otherwise, it should be smart and use
Running in Eclipse (2)
Running in Eclipse (3)
Running in Eclipse (4)
USB Debugging Should be enabled on phone to use developer features n In the main apps screen select Settings -> Applications -> Development -> USB debugging (it needs to be checked) n
Android Debug Bridge n Used for a wide variety of developer tasks ¨ Read from the log file ¨ Show what android devices are available ¨ Install android applications (. apk files) n In the ‘platform-tools’ directory of the main android sdk directory ¨ Recommend putting this directory and the ‘tools’ directory on the system path n adb. exe
Debugging n n Instead of using traditional System. out. println, use the Log class ¨ Imported with android. util. Log ¨ Multiple types of output (debug, warning, error, …) ¨ Log. d(<tag>, <string>) Can be read using logcat. ¨ Print out the whole log, which auto-updates n ¨ Erase log n ¨ adb logcat –c Filter output via tags n n n adb logcat <tag>: <msg type> *: S can have multiple <tag>: <msg type> filters <msg type> corresponds to debug, warning, error, etc. If use Log. d(), then <msg type> = D Reference ¨ http: //developer. android. com/guide/developing/debugging-log. html
Screen Shots Some say you need to root the phone – that is not true n One option: Android Screen Capture n ¨ http: //www. mightypocket. com/2010/08/android -screenshots-screen-capture-screen-cast/ ¨ It’s slow, but fine for screenshots of applications whose screens aren’t changing fast ¨ Read their installation help, following the extra steps if need be (I had to copy adb. exe and some dll files, as they explain)
Maps Example (1) n n n Using Google Maps in your app Setup project to use ‘Google API’ version Edit Manifest file ¨ To indicate the app will use maps and the internet Get a maps API key Note: Google Maps API can display a map and draw overlays, but is not the full Google Maps experience you enjoy on the web ¨ For example, there does not seem to be inherent support for drawing routes between points (if you find it let me know)…however, you can draw lines between points and almost any type of overlay, but that’s different than street routes ¨ The directions API is a web service, which is different, among several other Google web services Read the Google API terms of use
Maps Example (2)
Maps Example (3) – Manifest (1) n n Open Manifest file Add map library tag ¨ n Indicate the app will access the internet ¨ n Add the ‘Uses Library’ com. google. android. maps Add the ‘Permission’ android. permission. l. NTERNET End goal is to add the following two lines to XML file, under the <manifest> and <application tags>, respectively ¨ Under the <manifest> tag n ¨ Under the <application> tag n n <uses-permission android: name="android. permission. INTERNET"></uses-permission> <uses-library android: name="com. google. android. maps"></uses-library> Following is GUI way to add them
Maps Example (4) – Manifest (2) 1 2
Maps Example (5) – Manifest (3) Select ‘Add’ under ‘Uses Library’ (last slide) n Then select ‘Uses Library at this prompt n Set name as: com. google. android. maps (next slide) and save n
Maps Example (6) – Manifest (4)
Maps Example (7) – Manifest (5) 2 1
Maps Example (8) – Manifest (6) Select ‘Permissions’ and then ‘Add’ (last slide) n Select ‘Uses Permissions’ at this prompt n Set name to: android. permission. INTERNET and save (next slide) n
Maps Example (9) – Manifest (7)
Maps Example (10) – Maps API Key (1) n All Android applications need to be signed ¨ The debug mode signs for you with special debug certificate n All Map. View elements in map applications need to have an API key associated with them ¨ That key must be registered with the certificate used to sign the app n When releasing app, need to sign with a release certificate and get a new API Key
Maps Example (11) – Maps API Key (2) n For debug mode, get the MD 5 fingerprint of the debug certificate ¨ Locate the ‘keystore’ n n Windows XP: C: Documents and Settings<user>. androiddebug. keystore n ¨ Windows Vista: C: Users<user>. androiddebug. keystore OS X and Linux: ~/. android/debug. keystore Use Keytool (comes with Java, in the bin directory with the other Java tools, should put that dir on system PATH) to get fingerprint n keytool -list –v -alias androiddebugkey -keystore “<path_to_debug_keystore>” -storepass android -keypass android ¨ n n If don’t include –v option, then will probably get only 1 fingerprint, and if it’s not MD 5, then need –v (Java 7 needs –v) Extract the MD 5 fingerprint, SHA will not work unfortunately Go to https: //code. google. com/android/maps-api-signup. html , agree to terms and paste MD 5 fingerprint, you will then be given an API Key
Maps Example (12) n Need to put Map. View tag in XML com. google. android. maps. Map. View is the basic view that represents a Google Map display ¨ Must include API Key in XML, inside a layout ¨ ¨ n n <com. google. android. maps. Map. View android: id="@+id/mapview" android: layout_width="fill_parent" android: layout_height="fill_parent" android: clickable="true" android: api. Key=“<api key>”/> Maps API Reference ¨ http: //code. google. com/android/add-ons/google-apis/reference/index. html
Acknowledgements n n Android Developer’s Website ¨ Activity and Service life-cycle flow charts ¨ Tons of other Android info Google Maps API external library ¨ n Mighty. Pocket ¨ n http: //code. google. com/android/add-ons/google-apis/maps-overview. html http: //www. mightypocket. com/2010/08/android-screenshots-screen-capture-screen-cast/ Numerous Forums & other developer sites, including: ¨ http: //www. javacodegeeks. com/2011/02/android-google-maps-tutorial. html http: //efreedom. com/Question/1 -6070968/Google-Maps-Api-Directions http: //www. mail-archive. com/android-developers@googlegroups. com/msg 28487. html http: //android. bigresource. com/ threads http: //groups. google. com/group/android-developers threads Many http: //stackoverflow. com threads ¨ http: //www. anddev. org/google_driving_directions_-_mapview_overlayed-t 826. html ¨ ¨ ¨ n Zainan Victor Zhou – for advice and his own tutorial
Advanced Android Topics n The first mile on Android: relatively straight forward ¨ Should already know Java ¨ GUI is roughly drag and drop ¨ Lots of documentation and examples online… n Let’s get a little more advanced… ¨ Debugging on an Android device ¨ Persistent application storage (Preferences, Database) ¨ Writing and linking non-Java code (e. g. , C and C++) ¨ Cross-compiling useful libraries to Android ¨ Modifying the kernel (e. g. , to add support, remove permissions) ¨ NFC support
Some More Advanced Layouts n As mentioned, we have a research project on Android which uses a lot of advanced features and different layouts ¨ Good examples of how to embed layouts within each other… https: //github. com/gnychis/androidn These layouts are available in our project: wmon/tree/master/application/res/layout
Root: What do you need it for? n Like “jailbreaking” -- a term most are familiar with ¨ n What don’t you need it for? ¨ ¨ n Think of it as: it literally just gives you Linux root access Writing a standard application that uses standard APIs and HW Writing native code that does not touch some aspects of F. S. What do you need it for? ¨ Modifying and replacing the kernel n ¨ ¨ E. g. , to remove permission checks, modify TCP, modify Wi. Fi stack… Loading and/or removing new kernel modules Modifying anything in /system or snooping around /data Modifying the Android OS or APIs Changing the ROM on the device (new OS + kernel)
Debugging n As usual, two ways to have debug information: Android has a logging utility to print Tag Message information to 2. Full debugger through ADB and Eclipse 1. n Logging utility: good for printing periodic status of application and/or certain variables
Persistent Storage n You are likely going to want to persistently store data n In Android, there are 5 main ways to store data: Shared Preferences – private key-value pair storage 2. Internal Storage – private storage perapplication 1.
Shared Preferences Overview n Good for basic data storage, simple examples: ¨ Has the user completed the application settings? (boolean) ¨ What is the user’s username? (string) n Shared Preferences accessed by string key, value can be: ¨ boolean, float, int, long, string
Shared Preferences Example n Name preference file (does not need to be globally unique) n Get a handle to your preferences: n Can read in values by key, specify value if Do not forget does not exist
SQLite Database n Should hopefully know the basics of databases n Best to store your main data/objects ¨ Marshal your classes to and from a row in a database n Android provides some useful helper classes
Writing Native Code (JNI) n JNI: framework that allows Java code to call, or be called by, native applications/libraries in other languages ¨ E. g. , Java code can call a function written in C++, and visa-versa n Easiest way to integrate pre-existing code and libraries in other languages (e. g. , a pre-existing C encryption library) n Good to implement certain functionality which can be written more optimally in C, for example n Native code still runs within the application’s VM ¨ n Follows Android. Manifest (e. g. , need “INTERNET” for sockets) Android NDK: Toolset integrate/compile JNI in to Android app
The Structure of Native Code n Directory structure: native code fits in “jni” directory n ndk-build uses Android. mk in each native directory
Top-Level Android. mk n Best way to make top-level Android. mk: List each subdirectory for ndk-build to enter and build individually. n You can cross-reference in-between libraries ¨ E. g. , stringlib can use a function found in mathlib, the stringlib Android. mk file just needs to specify it links mathlib
Individual Library Android. mk n n Each library needs its own Android. mk, with: ¨ Local source files, linker/compiler flags, output (e. g. , shared lib) Something a little more advanced, for example: Creates lib_____. so (i. e. , libawmon. so)
Simple Native C Code Example Need to include JNI environment header, logging also useful __android_log_print(ANDROID_LOG_INFO, “Native. Math”, ”Error: %d”, eval); n Native function is passed … n ¨ Java environment: often used to allocate new Java objects ¨ Java class object: ¨ Your Parameters: any C/C++ primitives Must match your package name (case sensitive) Must match the class accessing and calling the native code (case sensitive)
Building NDK Code n Make sure ndk-build is in your PATH env. Variable ¨ Standard Android documentation should get you this far… n From the base of your application directory (outside jni dir): All of your built libraries are copied to libs/armeabi/ n
The Eclipse Gotcha n YOU MUST REFRESH YOUR DIRECTORY IN ECLIPSE!! ¨ Eclipse does not look for changes, even if you were to rebuild app n You must refresh every time you run ndk-build otherwise your changes will not be included n Maybe something built in to Eclipse now?
Accessing Native Code in Java n Must load each native library: e. g. , ¨ Can be done in any class or thread ¨ It is a blocking call, to keep in mind if loading large libraries… n Must create native function prototypes in respective classes: n Once done, you can access these functions directly:
Using External Libraries n “I need a library to help me with _____, but it is a n n standard C or Linux implementation” (e. g. , crypto library) Proceed in this order: 1. Google “____ Android” – many libraries already cross-compiled 2. Write custom Android. mk to cross-compile it You will be surprised how many libraries you find crosscompiled, and even if an older version: use their Android. mk
Cross-Compiling Libraries n n n For many libraries, look at the Makefile and see which source files it uses to build the library ¨ Add these sources to Android. mk “LOCAL_SRC_FILES” ¨ Use similar CFLAGS, LDFLAGS Common for libraries to link to pthread, remove –lpthread but keep most pthread code. Custom pthread force linked Look at the many examples online, including our own: ¨ libpcap, libnl, libgcrpyt, libglib, libgpg, libusb …. https: //github. com/gnychis/android-wmon/tree/master/application/jni
Modifying the Kernel n Several key steps to modifying the kernel… Obtaining the proper source code for HW + OS version n If you get the wrong kernel: phone will not boot (I’ll help you…) 2. Modifying the kernel (we’ll give you some pointers…) 3. Cross-compiling the kernel using the NDK 4. Installing the kernel (BE CAREFUL: CAN BRICK PHONE) n Best to use something called “Any. Kernel” package 1. n This needs to be done in Linux (e. g. , in a Virtual Machine)
Obtaining Kernel Source Code n n n The two possible phones you are using for this class: ¨ Galaxy Nexus: code name “maguro” (“tuna” for kernel) ¨ Galaxy S: code name “crespo” Best to start at this link: https: //android. googlesource. com/ Kernel source code depends on the HW, for you: ¨ Galaxy Nexus: https: //android. googlesource. com/kernel/omap. git ¨ Nexus S: https: //android. googlesource. com/kernel/sa 3. 0. 31 -g<hash> (i. e. , d 5 a 18 e 0) msung. git … make sure to drop the g that is n prepended to the hash In “About Phone” you can find your git kernel commit:
Building the Kernel n Build using cross-compiler provided by Google: n Setup your environment: n Checkout your kernel version: git checkout <hash> Setup with the proper configuration n ¨ ¨ n Galaxy Nexus: Nexus S: make tuna_defconfig make crespo_defconfig Finally, you can build with: make
Packaging the Kernel – Pt 1 n Need to create a ramdisk with the proper init scripts ¨ Can be extracted from the device, but we will provide you with it ¨ See example… n Modifications to ramdisk are needed if you want to: ¨ Load kernel modules on boot ¨ Set permissions to certain devices/files on boot ¨ Change the order services are initialized
Packaging the Kernel – Pt 2 n n n This is very tricky, and must be done properly or you will “brick” the phone, i. e. , it will not boot and must be repaired Install without building the entire OS by creating “update” ZIP ¨ Runs a script to mount FS and extract kernel & modules ¨ Usually includes system directory which is extracted What the updater script looks like for Galaxy Nexus:
Packaging the Kernel – Pt 3 n Example hierarchy of the update ZIP Boot image with kernel at root These are standard Specific to device, updater script MUST put all kernel modules in here that were rebuilt with kernel
Installing the Kernel n Need to use “recovery” mode on the phone to install ¨ Dedicated, bootable partition with recovery console n Put your updater zip on your SD card, then: Use recovery to install the ZIP
Kernel Pointers n Based on the project page, some kernel locations you might be interested in…. ¨ Wi. Fi Driver: drivers/net/wireless/bcmdhd ¨ TCP Protocol / Sockets: n net/ipv 4 n include/net ¨ Permissions (e. g. , sockets): kernel/capability. c
Near Field Communication n Low rate short distance wireless communication ¨ Approx. 10 centimeters supported ¨ 424 kbit/s across 13. 56 MHz n Current applications: payments, smart posters, check-ins… n Two major NFC modes: ¨ Reader / Writer mode ¨ Peer-to-Peer mode (emulate tags on Android) n Nexus S was first phone to really “mainstream” NFC
NDEF (NFC Data Exchange Format) n Standard data format created by NFC Forum n NDEF Messages: basic transportation mechanism ¨ Can contain one or more NDEF Records n NDEF Record: contain specific structure with payload ¨ TNF contains the record type (e. g. , URI)
Tag Read / Write Example n Start with basic tag read and write example ¨ Includes P 2 P mode ability n This was an example posted by Google that we modified to make a little more intuitive n Sample code was posted for you: https: //github. com/gnychis/stickynotes
The Basic NFC Permissions n As usual, you need to have Android permissions ¨ Important to specify minimum SDK ¨ Ensure that the phone has NFC support
Receiving NFC Tag Information n Remember, all information in Android is broadcast n For NFC, you register to receive TAG read broadcasts:
Registering for NFC Data n Specify that the Activity should receive NFC Intents: n Can specify which data types the application should receive: n Need a handle to the “NFC Adapter” (i. e. , hardware) n Apply and enable the filter in on. Resume()
Receiving the NFC Data – Pt 1 n Receive callbacks in “on. New. Intent()” you override:
Receiving the NFC Data – Pt 2 n n NDEF Messages come in as an array Then, you can go through the msgs array and get the payload:
Detecting Nearby Tag to Write n n Just like you registered to receive NFC tag data, you register to know when a tag is simply detected and then use it to trigger a write to it: When the user specifies to write, you enable this filter and use a software flag to know that you should write when the tag is detected nearby:
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