Post on 09-May-2015
description
• Roy Clarkson & Josh LongSpringSource, a division of VMware
1
Native Android Development Practices
@royclarkson
2
About Roy Clarkson (Spring Android Lead)
@royclarkson
2
About Roy Clarkson (Spring Android Lead)
@royclarkson
2
About Roy Clarkson (Spring Android Lead)
@starbuxman
3
About Josh Long (Spring Developer Advocate)
josh.long@springsource.com
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
Agenda
12
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
Easy to get started
15
• Programs are written in Java ( )
Easy to get started
15
• Programs are written in Java ( )
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
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
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
R.* refers to constants that Android code generates for you that correspond to “resources”
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); }
}
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
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
• 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>
you specify that an Activity is the primary one like this
Class is set relative to root package specified in manifest
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>
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
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/
Running the simple Activity
24
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
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
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
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
Dependency Injection on Android
• Lots of options– RoboGuice– Android Annotations– the Android way
40
Dependency Injection on Android
• 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!)
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
Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
41
Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
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
Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
used to inject other widgets or “views”
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
Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
used to inject Resources
used to inject other widgets or “views”
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
Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
used to inject other objects
used to inject Resources
used to inject other widgets or “views”
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
Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
42
Dependency Injection on Android
• 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
Beyond Dependency Injection
• 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
Beyond Dependency Injection
• 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
Inject another widget or “view”
44
Beyond Dependency Injection
• 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
Inject another widget or “view”
specify a resource id (it is optional)
44
Beyond Dependency Injection
• 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
Inject another widget or “view”
specify a resource id (it is optional)
Inject objects configured manually
44
Beyond Dependency Injection
• 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;}
45
Dependency Injection on Android
• The Android way – android applications all have required access to a single
“Application” class– You can override the Application class– Thus, instant singleton!
46
Dependency Injection on Android
• 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
Dependency Injection on Android
• 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; }}
register your global singleton services
extend the Application
46
Dependency Injection on Android
• 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; }}
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
Dependency Injection on Android
• The Android way
get a pointer to the Application
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
Dependency Injection on Android
• The Android way
access your service
get a pointer to the Application
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
Dependency Injection on Android
• 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
© 2011 SpringOne 2GX 2011. All rights reserved. Do not distribute without permission.
Q&A
49