Native Android Development with Spring
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This document discusses native Android development using Spring technologies. It introduces Spring for Android and Spring Mobile, with Spring for Android providing support for building native Android apps using Spring and Spring Mobile focusing on mobile web apps. It then covers using the Spring RestTemplate for making REST calls in Android apps, demonstrating a basic example. Finally, it discusses additional Spring for Android features and resources for native Android development with Spring.
Native Android Development with Spring
- 1. Native Android Development with Spring Roy Clarkson Spring Mobile Projects Lead SpringSource, a division of VMware @royclarkson @springandroid © 2010 SpringSource, A division of VMware. All rights reserved 2012
- 2. Introduction § What are the purposes of the Spring for Android and Spring Mobile projects? • Spring for Android provides support for building native Android applications utilizing Spring technologies, where applicable. • In contrast, Spring Mobile provides support for building mobile web applications. CONFIDENTIAL 2
- 3. Spring for Android • Android Overview • Define the Problem • Review of REST • Basic Rest Template Example • Rest Template Overview • Maven Can Help • Showcase and Demos • Questions CONFIDENTIAL 3
- 4. Android Adoption § Year-on-year growth rate of more than 250% § 850,000 new Android devices are activated each day § Over 300 million devices around the world § Over 450,000 apps available in Google Play § Over 1 billion app downloads per month http://googlemobile.blogspot.com/2012/02/androidmobile-world-congress-its-all.html CONFIDENTIAL 4
- 5. Android Fragmentation § Current Distribution • Gingerbread 62% • Froyo 25.3% • Eclair 6.6% • Honeycomb 3.3% • Ice Cream Sandwich 1.6% http://developer.android.com/resources/dashboard/platform-versions.html CONFIDENTIAL 5
- 6. Android is Familiar Applications are written in Java! (well, sort of) CONFIDENTIAL 6
- 7. But not that Familiar... § Class Files • Android apps are compiled to class files. § DEX Format • Classes are compiled into the Dalvik Executable (DEX) format. • DEX format is required to run on the Dalvik Virtual Machine. § Dalvik VM • Not a true Java VM, because it does not operate on Java byte code. • Based on a subset of the Apache Harmony project. • Many of the classes from Java SE are available, but not all. CONFIDENTIAL 7
- 8. Isolation of an App § Unique Linux User ID • Android OS assigns each app a unique Linux user ID. § Process Isolation • Within the VM, each app runs in its own Linux process. § Managed Lifecycle • The system manages the starting and stopping. CONFIDENTIAL 8
- 9. Components of an Android App § Activities - An activity represents a single screen with a user interface. § Services - A service is a component that runs in the background to perform long-running operations or to perform work for remote processes. § Content Providers - A content provider manages a shared set of application data. § Broadcast Receivers - A broadcast receiver is a component that responds to system-wide broadcast announcements. http://developer.android.com/guide/topics/fundamentals.html CONFIDENTIAL 9
- 10. Android Manifest § contains the permissions requested by the app § Lists all of the components of an app <uses-sdk android:minSdkVersion="10" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:name=".HelloAndroidActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> CONFIDENTIAL 10
- 11. A simple Activity package org.springsource; import android.app.Activity; import android.os.Bundle; public class HelloAndroidActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); } } CONFIDENTIAL 11
- 12. STS and the ADT Plugin for Eclipse HelloAndroid Demo http://www.springsource.org/springsource-tool-suite-download http://developer.android.com/sdk/eclipse-adt.html CONFIDENTIAL 12
- 13. How can Maven help? § Android4Maven • This project compiles android.jar from source and pulls out source and resource files to replicate android.jar in the SDK • http://sourceforge.net/projects/android4maven/ § Maven Android SDK Deployer • If you need to use Google maps, then you have to go this route • https://github.com/mosabua/maven-android-sdk-deployer § Android Maven Plugin • Provides support for Maven dependency management within Android projects • http://code.google.com/p/maven-android-plugin/ CONFIDENTIAL 13
- 14. Android Maven Plugin Configuration <packaging>apk</packaging> <plugin> <groupId>com.jayway.maven.plugins.android.generation2</groupId> <artifactId>android-maven-plugin</artifactId> <version>3.1.1</version> <configuration> <sdk> <platform>${android-platform}</platform> </sdk> <deleteConflictingFiles>true</deleteConflictingFiles> <undeployBeforeDeploy>true</undeployBeforeDeploy> </configuration> <extensions>true</extensions> </plugin> https://repository.sonatype.org/index.html#nexus-search;quick~com.google.android CONFIDENTIAL 14
- 15. Maven Commands Build your Android App $ mvn clean install Start the Emulator $ mvn android:emulator-start Deploy the app to the emulator $ mvn android:deploy Run the app $ mvn android:run http://maven-android-plugin-m2site.googlecode.com/svn/plugin-info.html CONFIDENTIAL 15
- 16. Maven Demo CONFIDENTIAL 16
- 17. m2eclipse Support § Android Configurator for M2E Maven Integration for Eclipse • An Eclipse plugin that adds support for integrating m2eclipse, Android Developer Tools, and the Android Maven Plugin • http://rgladwell.github.com/m2e-android/ § Maven Android archetypes • This project provides several Maven archetypes for Android. These archetypes allow you to quickly bootstrap a Maven project to develop an android application. • https://github.com/akquinet/android-archetypes CONFIDENTIAL 17
- 18. This sounds too good! @rgladwell CONFIDENTIAL 18
- 19. Spring for Android CONFIDENTIAL 19
- 20. What problem are we trying to solve? § Concerns • REST has become a popular choice for architecting both public and private web services • The Android runtime provides HTTP clients capable of making HTTP connections and requests, but it does not have a fully featured REST client § Spring for Android Solution • The goal of Spring for Android Rest Template is to provide an easy to use, and functional REST client that supports marshaling objects from XML and JSON. CONFIDENTIAL 20
- 21. REST § Origin • The term Representational State Transfer was introduced and defined in 2000 by Roy Fielding in his doctoral dissertation. § His paper suggests these four design principles: • Use HTTP methods explicitly. • POST, GET, PUT, DELETE • CRUD operations can be mapped to these existing methods • Be stateless. • State dependencies limit or restrict scalability • Expose directory structure-like URIs. • URI’s should be easily understood • Transfer XML, JavaScript Object Notation (JSON), or both. • Use XML or JSON to represent data objects or attributes CONFIDENTIAL 21
- 22. Basic Rest Template Example § Google search example RestTemplate restTemplate = new RestTemplate(); String url = "https://ajax.googleapis.com/ajax/services/search/web?v=1.0&q={query}"; String result = restTemplate.getForObject(url, String.class, "SpringSource"); § Multiple parameters example RestTemplate restTemplate = new RestTemplate(); String url = "http://example.com/hotels/{hotel}/bookings/{booking}"; String result = restTemplate.getForObject(url, String.class, "42", “21”); CONFIDENTIAL 22
- 23. Google Search Demo CONFIDENTIAL 23
- 24. Spring for Android Rest Template § Based on SpringFramework • Originated as a fork of RestTemplate from SpringFramework. • Modifications were made to support Android. § RestTemplate class is the heart of the library • Entry points for the six main HTTP methods • DELETE - delete(...) • GET - getForObject(...) • HEAD - headForHeaders(...) • OPTIONS - optionsForAllow(...) • POST - postForLocation(...) • PUT - put(...) • any HTTP operation - exchange(...) and execute(...) CONFIDENTIAL 24
- 25. HTTP Clients § SimpleClientHttpRequestFactory • Delegates to the standard J2SE facilities § HttpComponentsClientHttpRequestFactory • Delegates to the native HttpComponents HttpClient § CommonsClientHttpRequestFactory (deprecated) • Delegates to the Commons HttpClient which is not native to Android CONFIDENTIAL 25
- 26. Message Converters § MappingJacksonHttpMessageConverter • object to JSON marshaling supported via the Jackson JSON Processor § SimpleXmlHttpMessageConverter • object to XML marshaling supported via the Simple XML Serializer § SyndFeedHttpMessageConverter • RSS and Atom feeds supported via the Android ROME Feed Reader CONFIDENTIAL 26
- 27. Spring for Android Showcase § Examples • HTTP GET • JSON • XML • HTTP GET with Parameters • JSON • XML • HTTP POST • String • JSON • XML • MultiValueMap • RSS • ATOM CONFIDENTIAL 27
- 28. Rest Template Demos CONFIDENTIAL 28
- 29. Spring Social on Android § What is Spring Social? • Spring Social is an extension of the Spring Framework that allows you to connect your applications with Software-as-a-Service (SaaS) providers such as Facebook and Twitter. § How does it relate to Spring for Android? • Utilizes RestTemplate to make RESTful requests to providers. § How can Spring for Android help? • Auth library in Spring for Android provides a SQLiteConnectionRepository for use with Spring Social. CONFIDENTIAL 29
- 30. Additional Resources § Slides: • http://portal.sliderocket.com/vmware/Native-Android-Development-with-Spring § Project Home: • http://www.springsource.org/spring-android § Sample Code: • https://github.com/SpringSource/spring-android-samples § Webinar: • http://www.springsource.org/node/3505 § Blog Posts: • http://blog.springsource.com/author/rclarkson/ CONFIDENTIAL 30