roy clarkson & josh longwhiteship.me/wp-content/uploads/2011/11/one_up_android.pdf · • roy...

• Roy Clarkson & Josh LongSpringSource, a division of VMware

1

Native Android Development Practices

Saturday, October 29, 11

@royclarkson

2

About Roy Clarkson (Spring Android Lead)


@starbuxman

3

About Josh Long (Spring Developer Advocate)

[email protected]


mailto:[email protected]

mailto:[email protected]

Spring Mobile

• Provides support for developing mobile web applications– Builds on Spring MVC, focuses on server-side support– Compliments client-side mobile frameworks

• Key Features– Device Detection– Site Preference Management– Site Switcher

4


Device Detection

• Useful when requests by mobile devices need to be handled differently from requests made by desktop browsers

• Introspects HTTP requests to determine the device that originated the request.– Achieved by analyzing the User-Agent header and other

request headers– In contrast to “Feature Detection” where client detects

available features

• Spring Mobile provides a DeviceResolver abstraction and interceptor

5


Device Detection Demo

6


Site Preference Management

• Device detection is often used to determine which "site" will be served to the user– Mobile site vs. desktop site

• Spring Mobile also provides support for “site preference management”

• Allows the user to indicate whether he or she prefers the mobile site or the normal site

• Remembers the user’s preference for their session

7


Site Preference Demo

8


Site Switcher

• Some applications may wish to host their "mobile site" at a different domain from their "normal site"– For example, Google will switch you to m.google.com if you

access google.com from your mobile phone

• SiteSwitcherHandlerInterceptor can be used to redirect mobile users to a dedicated mobile site

• Supported SiteSwitchers– mDot - m.example.com– dotMobi - example.mobi

9


Site Switcher Demo

10


Limitations of Mobile web sites

• they can’t access the native capabilities of the phone• they require network access (no offline support)• formatting an application to look mobile is different than

actually being a mobile application

11


Agenda

12


An Introduction to Android!

13

More than 500,000 activations every day


An Introduction to Android!

• Huge and growing ecosystem ofapplications and a market to boot

14

8.1 billion app downloadsAndroid Market PlaceApple App Store 6 billion

* http://news.cnet.com/8301-1035_3-20103230-94/android-to-overtake-apple-in-app-downloads/

Expected downloads in 2011


http://news.cnet.com/8301-1035_3-20103230-94/android-to-overtake-apple-in-app-downloads/

http://news.cnet.com/8301-1035_3-20103230-94/android-to-overtake-apple-in-app-downloads/

Easy to get started

15

• Programs are written in Java ( )


Easy APIs and concepts

• no real “applications,” only loosely coupled components

16

Activities describes the unit of work for one screen

Services does background work like synchronization with a cloud service

Content Providers component that knows how to render and manipulate content of a certain type

Broadcast Receivers knows how to receive and respond to system-wide events like screen shutoff.

* http://developer.android.com/guide/topics/fundamentals.html


http://developer.android.com/guide/topics/fundamentals.html

http://developer.android.com/guide/topics/fundamentals.html

A Simple Activity

17

package org.springframework.android.activities;

import android.app.Activity;import android.os.Bundle;

public class HelloAndroid extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); }

}


You *must* extend Android classes to build proper components

A Simple Activity

17




}


You *must* extend Android classes to build proper components

R.* refers to constants that Android code generates for you that correspond to “resources”

A Simple Activity

17




}


Declaring the Simple Activity

18

<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/textview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:text="@string/hello"/>

/res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?><resources> <string name="hello">Hello, Android! I am a string resource!</string> <string name="app_name">Hello, Android</string></resources>

/res/values/strings.xml


http://schemas.android.com/apk/res/android

http://schemas.android.com/apk/res/android

Lifecycle

• Android controls lifecycles of these components• Registered in manifest

19

<activity android:name=".activities.HelloAndroid android:label="@string/app_name" android:theme="@android:style/Theme.NoTitleBar"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter></activity>


Class is set relative to root package specified in manifest

Lifecycle


19



you specify that an Activity is the primary one like this

Class is set relative to root package specified in manifest

Lifecycle


19



Android Sample Demo

• How to use STS and the Android Eclipse plugin

20


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

• Maven Android Plugin– Provides support for Maven dependency management within

Android projects– http://code.google.com/p/maven-android-plugin/

21


http://sourceforge.net/projects/android4maven/

http://sourceforge.net/projects/android4maven/

https://github.com/mosabua/maven-android-sdk-deployer

https://github.com/mosabua/maven-android-sdk-deployer

http://code.google.com/p/maven-android-plugin/

http://code.google.com/p/maven-android-plugin/

Maven Android Plugin Configuration

22

<plugins> <plugin> <groupId>com.jayway.maven.plugins.android.generation2</groupId> <artifactId>maven-android-plugin</artifactId> <version>2.8.4</version> <configuration> <sdk> <platform>3</platform> </sdk> <emulator> <avd>3</avd> </emulator> <deleteConflictingFiles>true</deleteConflictingFiles> <undeployBeforeDeploy>true</undeployBeforeDeploy> </configuration> <extensions>true</extensions> </plugin>


m2eclipse Support

• Maven Integration for Android Development Tools– An Eclipse plugin that adds support for integrating

m2eclipse, Android Developer Tools, and the Maven Android Plugin

– http://code.google.com/a/eclipselabs.org/p/m2eclipse-android-integration/

• Maven Android archetypes– This projects 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

23

http://blog.springsource.com/2010/12/17/spring-android-and-maven-part-1/http://blog.springsource.com/2010/12/17/spring-android-and-maven-part-2/


http://code.google.com/a/eclipselabs.org/p/m2eclipse-android-integration/




https://github.com/akquinet/android-archetypes

https://github.com/akquinet/android-archetypes

http://blog.springsource.com/2010/12/17/spring-android-and-maven-part-1/




Running the simple Activity

24


25

...what about something a bit more non-trivial?


26

Spring’s aim:

bring simplicity to java development

modern web data access integration mobile social security

tc ServerTomcatJetty

lightweightCloudFoundry

Google App EngineAmazon Web Services

BeanStalkHeroku

the cloud: WebSphereJBoss ASWebLogic

(on legacy versions, too!)

traditional

The Spring framework

security

Enter Spring Android!


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 Android Solution– The goal of Spring Android Rest Template is to provide an

easy to use, and functional REST client that supports marshaling objects from XML and JSON.

27


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

28


http://en.wikipedia.org/wiki/Roy_Fielding

http://en.wikipedia.org/wiki/Roy_Fielding

Basic Rest Template Example

29

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");

RestTemplate restTemplate = new RestTemplate();String url = "http://example.com/hotels/{hotel}/bookings/{booking}";String result = restTemplate.getForObject(url, String.class, "42", “21”);

Google search example

Multiple parameters


http://livepage.apple.com/




Demo

• Using Spring Android to communicate with a RESTful web service (Google Search Demo)

30


Spring Android Rest Template

• Based on SpringFramework– The majority of the supporting classes are pulled 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(...)

31


Spring Android Rest Template

• Http Client– The HttpComponents HttpClient is a native HTTP client

available on the Android platform.– HttpComponentsClientHttpRequestFactory

• 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

32


http://hc.apache.org/httpcomponents-client-ga/index.html

http://hc.apache.org/httpcomponents-client-ga/index.html

Spring Android Showcase

• Examples– HTTP GET

• JSON• XML

– HTTP GET with Parameters• JSON• XML

– HTTP POST• String• JSON• XML• MultiValueMap

– HTTP and GZIP

33


Spring Android Demos

• Spring Android Showcase Demo

34


Spring Social on Android

• Supports connecting to supported Spring Social services• uses same RESTful connectivity based on RestTemplate

35


Enter Spring Android!

36


37

do NOT reinvent the Wheel!


38

Dependency Injection on Android

• Problems with DI on Android– hard reliance on base classes– hard reliance on Android to manage the runtime lifecycle

• a POJO peer system would have been onerous


39


• Lots of options– RoboGuice– Android Annotations– the Android way


40


• RoboGuice (http://code.google.com/p/roboguice/)– Pros:

• requires you to extend RoboApplication• You must configure your beans using the

AbstractAndroidModule• Each Activity must extend from RoboActivity

– Cons:• no AOP• not small, at all!

– (400kb to a mobile application may as well be 400MBs to your enterprise application!)


http://code.google.com/p/roboguice/


public class MyActivity extends Activity { private TextView label; private Drawable image; private SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); this.label = (TextView) findViewById(R.id.mylabel); this.image = getResources().getDrawable(R.drawable.myimage); this.searchManager = (SearchManager) getSystemService(Activity.SEARCH_SERVICE); }}

before RoboGuice

41


• RoboGuice (http://code.google.com/p/roboguice/)




41






public class MyActivity extends RoboActivity { @InjectView(R.id.mylabel) TextView label; @InjectResource(R.drawable.myimage) Drawable image; @Inject SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); }}

with RoboGuice

41






used to inject other widgets or “views”


with RoboGuice

41






used to inject Resources



with RoboGuice

41






used to inject other objects

used to inject Resources



with RoboGuice

41






42


• RoboGuice (http://code.google.com/p/roboguice/)– Pros:

• requires you to extend RoboApplication• You must configure your beans using the

AbstractAndroidModule• Each Activity must extend from RoboActivity

– Cons:• no AOP• not small, at all!

– (400kb to a mobile application may as well be 400MBs to your enterprise application!)

• runtime inefficiency




43

Beyond Dependency Injection

• Android Annotations(http://code.google.com/p/androidannotations/)– Pros:

• compile-time code generation means no runtime cost• can be used side-by-side with RoboGuice

– Cons:• extra build step• some redundancy with RoboGuice




44


• Android Annotations(http://code.google.com/p/androidannotations/)

@EActivity(R.layout.myactivity) public class MyActivity extends Activity { @InjectView TextView mylabel; @DrawableRes(R.drawable.myimage) Drawable image; @SystemService SearchManager searchManager;}




sets the layout

44







sets the layout

Inject another widget or “view”

44







sets the layout


specify a resource id (it is optional)

44







sets the layout


specify a resource id (it is optional)

Inject objects configured manually

44







45


• The Android way – android applications all have required access to a single

“Application” class– You can override the Application class– Thus, instant singleton!


46


• The Android way public class MainApplication extends Application { private MyService service; @Override public void onCreate() { super.onCreate(); service = new MyServiceImpl(); } public MyService getMyService() { return this.service; }}


extend the Application

46




register your global singleton services

extend the Application

46




public class MainActivity extends Activity { private MyService service; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); MainApplication app = (MainApplication) getApplication(); service = app.getMyService(); }}

47


• The Android way


get a pointer to the Application


47


• The Android way


access your service

get a pointer to the Application


47


• The Android way


Additional Resources

• Project Home– http://www.springsource.org/spring-android– http://www.springsource.org/spring-mobile

• Sample Code– https://github.com/SpringSource/spring-android-samples.git– https://github.com/SpringSource/spring-mobile-samples.git

• Blog Posts– http://blog.springsource.org

48


http://www.springsource.org/spring-android

http://www.springsource.org/spring-android

http://www.springsource.org/spring-mobile

http://www.springsource.org/spring-mobile

https://github.com/SpringSource/spring-android-samples.git

https://github.com/SpringSource/spring-android-samples.git

https://github.com/SpringSource/spring-mobile-samples.git

https://github.com/SpringSource/spring-mobile-samples.git

http://blog.springsource.org

http://blog.springsource.org

roy clarkson & josh longwhiteship.me/wp-content/uploads/2011/11/one_up_android.pdf · • roy...

Documents