Setup eclipse & android project for aspect oriented programming(AOP)

Pre-req: you should familiar with eclipse, know android programming and have knowledge of AOP.

Hi guys,

           Software development with Aspect oriented programming(AOP) is very popular these days. Because it is easy use and apply. And we can achieve good level of modularity and re-usability in our software architectures.
So I decide to deliver a presentation in my office. While preparing presentation I am writing this blog. The idea of my presentation is to introduce AOP and explain it with a demonstration (Sample), My sample will show how we can use AOP in android development. I will surly write blogs on android development with AOP but step by step.

AOP is also useful in enhancing legacy systems. By that I mean if you dont want to change existing code of system then create new modules in AOP. It will help you to keep separate no code with old one.

So lets start with step up eclipse and create a hello world android project with AOP.

Install AOP tool for eclipse:

1) Open eclipse and go to eclipse market place. Type AJDT (AspectJ Development Tools) in search bar. Choose respective plugin for eclipse. I am going to use Aspectj for compilation.

2) For example for my juno eclipse it is

3) Download and install then restart eclipse

Create android project:

Assuming you guys know how to create android project.

Fix android project for aspects

1) Right click android project and go to Configure and then Convert to AspectJ project. By doing that compile time errors will be remove and you can start creating aspects.

 

2)  Know create a prospect , I am creating aspect to print some words on start and end of onCreate() function in activity

3) Right click and run android project , you can see the printing in logs below

Source code is attacthed

Native Android Client Architecture And Frameworks

Hi guys,

We all know principle of kiss. We should keep our software architectures simple as possible. One way to do that is decide architecture and narrow down the problem before going for solution/decisions. Choose good frameworks/plugins, this will make your code simple and readable. And of-course this strategy encourages re-usability, which is a way of fast development.


In this post I will try to simplify client application architecture (android client-server model) and provide list of famous frameworks. To solve solution of

• Threads
• Network operations
• Cache/database
• Re-usability 

Flow of application will be like below

So upon request or event trigger

• First apply validations
• Call service to execute request
• Service with execute it can initiate thread to fetch data from server, or read from database(cache) or other facilitate other kind of requests
• Service will return model, some data or exception
• Services here are not android service. This layer helps you to reuse code in activities/fragments.

So what frameworks we can use in this architecture

   1.   View (Activity/Fragments)

           For view we have 

• Robojuice  It help to bind xml view(gui), resources with objects. These annotation reduce line of code and enhance readability. 
• Actionbarsherlock. Helps in managing navigation between view, standardization of actions for view, menu buttons on page for android 4.0+   
• Droid4me helps you handling activity/fragment life cycle, exception handling , thread management, intra-component communication, file download management.

   2. Validations

•  You can use my work utils jar.
• Apache commons-validator, has xml validations and common validation methods (email addresses, dates, URLs, etc.)

   3. Thread

•  For thread you can use Async tasks
• You can use Robospice. It provides solution for threading, parsing data (xml, json), notification to view, exception handling.
• You can use Droid4me for thread management.

   4.  Database manager

• OrmLite use to create persist objects. So you dont need to populate objects after query and write code for operations like insertion, deletion, update etc your self.
• Sqlitegen, use to create DAOs(data access object), easy to convert query results into object. 
• ActiveAndroid allows you to save and retrieve SQLite database records without ever writing a single SQL statement. Each database record is wrapped neatly into a class with methods like save() and delete().

   5.  Network Manager 

• Spring Restful helps communicating with servers over http, https protocols, methods can be post, get, put, delete. You can parse response direct into json, xml with the support of gson, jackson and other parsers for xml and json. (Recommended)
• Use  Android-query to get json, xml, inputstream, files from server.

Dependency injection android (roboguice review)

Pre-req: you should know about development in android.
I am using: For this tutorial I am using windows xp, maven, android 2.33 , spring restfull android, robojuice

Hi guys,


People those are familiar with spring and Inversion of control, They knows that IOC provides good level of abstraction in managing object(s) i.e initializations, object management, association management. And also decrease lines of code. So lets see roboguice.

To install this first create a maven base project.


1) Add dependencies for roboguice into the project (POM.XML).

 <dependency>
     <groupId>org.roboguice</groupId>
     <artifactId>roboguice</artifactId>
     <version>2.0</version>
  </dependency>

            <dependency>
               <groupId>com.google.code.findbugs</groupId>
               <artifactId>jsr305</artifactId>
              <version>1.3.9</version>

           </dependency>
Reference


2) What we have?
    We can megre 2 steps i.e declaration and initialization, we can avoid object creation and management on different  level (code liens) at class level.

• Shared Preferences
• Content Resolver
• Asset Manager
• Resources
• Location Manager
• Window Manager
• Layout Inflater
• Activity Manager
• Power Manager
• Alarm Manager
• Notification Manager
• Keyguard Manager
• Search Manager
• Vibrator Manager
• Connectivity Manager
• Wifi Manager
• Input Method Manager
• Sensor Manager

We can create service and bind it with our activities/fragments. This provides alot of ease in fast development.

we can also bind android resources string/arrays/color/config etc to objects.

Reference

3) List of warped components 
   Robo juice warped many android components, list of these components are below

• RoboActivity
• RoboListActivity
• RoboExpandableListActivity
• RoboMapActivity
• RoboPreferenceActivity
• RoboAccountAuthenticatorActivity
• RoboActivityGroup
• RoboTabActivity
• RoboFragmentActivity
• RoboLauncherActivity
• RoboService
• RoboIntentService
• RoboFragment
• RoboListFragment
• RoboDialogFragment

To use feature of robojuice, all you need is to extend your components with one of respective above warped components. for example if you want to use robojuice dependency management in your activity then extent your class with  RoboActivity  instead of Activity.

4) Create and activity
  Lets create a activity with robojuce, lets say we have  list of software houses.
 So I have a list of software houses in string.xml

 and my activity is like below:

5) Lets create a factory to execute web service calls (Powered by Spring rest for android)

i) Create an interface  ResponseFctory 

ii) Create implementation of ResponseFctory , 
       Add annotation @Singleton on the top of implementation, because we are creating a factory of singleton scope.

iii) Create configuration file to bind Interface with implementation
   A class extends AbstractModule and bind interface with implementation in configure function
with command

bind(ResponseFctory.class).to(ResponseFactoryImpl.class); 

below is example

iv) Register custom AbstractModule  with robojuice 
Create a robojuice.xml file in res/values folder. Add path of your Configuration class like below

<resources>
    <string-array name="roboguice_modules">
        <item>com.testguice.config.Configuration</item>
    </string-array>
</resources>

v) Use this factory inside your activity like below

6) Benefits

i) Decrease association. We can bind parameters with function. Hence increase decoupling.
ii) Promote polymorphism, Singeltons and interfaces. Hence increase decoupling.
iii) Object creation and management. you dont need to initialize objects on different level (lines in code) of class.. Hence increase readability
vi) Decrease lines of code. Enforce  best practices.

Source code available.

Review Twitter Bootstrap

Using: For this tutorial I am using Netbean IDE , windows xp plateform, php as server side language.
Pre-req: You should know about html, java script and css.

Preview my work here

I was looking into twitter bootstrap so here is my findings.


A) Structure of application:
    All you need is download , extract and and put the folders into your application. It has js, css and img folders. you can use it with any server side language. For demonstration I am using php. So after putting the files my project lookes like below:

B) Structure of web page:
    For creating a web page, we have 2 options
    1) Use Table structure/layout to display your contents.
     2) Use Divs  to show contents , then you need to concentrate on css to set thes div on required positions,

  Twitter Bootstrap solves layout issues. They provide css of div to divid your pages into rows and columns. So we dont need to worry about  positions of the Divs to show our contents.

   <div class="row">
        <div class="span1">contents 1</div>
        <div class="span1">contents 2</div>
 </div>

Column span levels are from 1 to 12.


Responsive Bootstrap: They have css/style created for tabs, mobiles and desktop. So your structure can easily adjust for device and desktop. All you need is to include a meta tag and css file

1. <meta name="viewport" content="width=device-width, initial-scale=1.0">
2. <link href="assets/css/bootstrap-responsive.css" rel="stylesheet">

Their recommendation: Use on a limited basis and avoid creating entirely different versions of the same site. Instead, use them to complement each device's presentation. Responsive utilities should not be used with tables, and as such are not supported.   (Reference)

So I  made a sample page with rows and colums on desktopn this lookes like

On mobile phone it lookes like below:

C) Widgets
     We have list of wigets below. These can are adjustable on both devices and destops. So that means you can use intratcive and cool wedgits on your mobile applications.

1.  Button groups 
2.  Button dropdowns 
3.  Navigational tabs, pills, and lists 
4.  Navbar 
5.  Labels 
6.  Badges 
7.  Page headers and hero unit 
8.  Thumbnails 
9.  Alerts 
10.  Progress bars 
11.  Modals 
12.  Dropdowns 
13.  Tooltips 
14.  Popovers 
15.  Accordion 
16.  Carousel 
17.  Typeahead 

References1 and Reference2

So here is a view on desktop

and how the look on mobile device

D) Javascript
    Here we have

1. Event handling (like we do in web app i.e clicks, selections, display, inrection etc
2. Transitions 
3. Custom popup called Modals 
4. Tooltips
5. Carousel

  Reference

E) Style
     There are amazing style sheets available that workes for mobiles, tabs and destop. You can create beautiful headings, labels, buttons, meues , carosels, thumnails etc. It provides redability on mobile devices.

Reference

F) Customization

   We can easily customize our applications. And with it we can create application for both mobile and dektops. It will definitly decrease the development cost. Because I have noticed that web developer spent most of the time in adjectment of contents position on page and we put extra efforts to make our web pages compatible with mobile browsers. In twitter bootsrap javascript is very usefull, provides all kind of event handling that we need in a web application.

Android Common Utilities

Hi guys,

In android projects there are many programs/commands we use frequently. Most of the time we implement these programs from scratch or take these program files from existing projects and refactor to adapt into new projects, This process take time. So I decide to put these programs together as much I can. So that developers can use them and reduce their development time. These days I am looking at every possibility to decrease the development time. This is one of my steps.

Pre-req: You should know how to create android project. Then download AndroidCommonUtils.jar jar and put into your project.

In this package we have these classes

    1. ActivityDTO

            Use Map (data structure) in this class, To pass data from activities to other components, Because I have seen under the development cycle, Most of the time we need to refactor functions and need to add or remove parameters, and some time functions took large number of parameters. So adding removing function parameters takes time. So this is my suggestion you can do following thing.

                ActivityDTO activityDTO = new ActivityDTO();
       activityDTO.getMap().put("activity", this);
       activityDTO.getMap().put("progressBarThread", progressBarThread);
       activityDTO.getMap().put("appDebuger",appDebuger);
       activityDTO.getMap().put("userConfigDb",userConfigDb);
     
LoginTask loginTask = new LoginTask(activityDTO);
loginTask.execute(userDTO);

Above example demonstrates how I am  sending different objects into  LoginTask constructor.And inside constructor I can get back these objects.

public LoginTask(ActivityDTO activityDTO) {
activity = (LoginActivity)activityDTO.getMap().get("activity");
progressBarThread =(ProgressThreadUtils)activityDTO.getMap().get("progressBarThread");
appDebuger = (AppDebuger)activityDTO.getMap().get("appDebuger");
userConfigDb = (UserConfigDb)activityDTO.getMap().get("userConfigDb");
}

     2.  AppDebuger
         This utility has methods to print logs on screen for purpose of debugung. I am using Singleton Pattern, Developer can on/off debuging from any where.

          AppDebuger appDebuger = AppDebuger.init();
          appDebuger.setOn(true);
          appDebuger.printInfo("Printhing from blog" , "1234");

    3. CommonMessagesUtils 
        This class has methods to show Toast messages and Dialog Messages.

    4. CommonValidationsUtils
        This class has methods to validate email, strings, password, convert stream into string, check strings are alpha numeric, decimal adjustment. ect

     5. DAOTemplate
           This class has method to insert, delete, remove, update, open close db connections almost every method that will help you to play with you database.
To use do like this
    
    6.  PrivateSharedPrefeqencesForStringsUtils
        This class has methods to save,remove and get presistant strings from android SharedPrefeqences.

    7.  ProgressThreadUtils
         This is a thread utility to manage progress dialog on you activities, State of thread is mentioned in ProgressThreadState enum. Inside your activity use this thread like this


    8.   SDCardUtils

        This class has all methods to save, retrieve files from sd card, you can download resources from internet into sd card and retrieve these as file or bitmap


Download source.

Use HTTPS connection in android app

Note : For this tutorial I am using Ubuntu platform 


1) If you are working on android application with client - server model. And services expose by servers are on SSL connection (i.e https://myserver/login?email=&password) then you need settings in your android applications.


1) Download the certificate. for demonstration I am using a link (i.e https://www.google.com) and chrome browser.
  a) Open chrome and this link : https://www.google.com
  b) Press Lock icon on you url bar and then select Connection tab
  c) Then select Certificate information
  d) You will see a pop up. Select details tab and Select top of Hierarchy under  Certificate Hierarchy section.
   e) press export button and save certificate in you directory.

f)  Certificate will be like :
-----BEGIN CERTIFICATE-----
MIIDIDCCAomg..........................................
-----END CERTIFICATE-----

2) Download  BouncyCastle Provider and put it will you SSL certificate file.
3) Open terminal and open your Oracle JDK bin folder
    cd /usr/lib/jvm/java-7-oracle/bin

4) use blow command to create a keystore file mykeystore.bks with

 password mysecret

keytool -importcert -v -trustcacerts -file "/path/Builtin Object Token:Equifax Secure CA" -alias IntermediateCA -keystore "/path/mykeystore.bks" -provider org.bouncycastle.jce.provider.BouncyCastleProvider -providerpath "/path/bcprov-jdk16-145.jar" -storetype BKS -storepass mysecret

5) To verify mykeystore.bks use below command on same terminal

keytool -list -keystore "/path/mykeystore.bks" -provider org.bouncycastle.jce.provider.BouncyCastleProvider -providerpath "/path/bcprov-jdk16-145.jar" -storetype BKS -storepass mysecret

you will get result like

Keystore type: BKS
Keystore provider: BC

Your keystore contains 1 entry

IntermediateCA, Mar 14, 2013, trustedCertEntry,
Certificate fingerprint (SHA1): D2:32:09:AD:23:D3:14:23:21:74:E4:0D:7F:9D:62:13:97:86:63:3A

 6) Now put mykeystore.bks in to your android project/res/raw/mykeystore.bks


7) Now use  mykeystore.bks into get response input stream from your request.
    you can get code here 

private static InputStream getHttpInputStream(String urlAddress,Context ctx)  throws KeyManagementException, NoSuchAlgorithmException, CertificateException, IOException, KeyStoreException, UnrecoverableKeyException{
        TrustManagerFactory tmf;
       
        KeyStore trustedStore = loadClientKeyStore(ctx);
        tmf = TrustManagerFactory.getInstance("X509");
        tmf.init(trustedStore);

        SSLContext ssl_context = SSLContext.getInstance("TLS");
        ssl_context.init(null, tmf.getTrustManagers(), null);
       
       
        HostnameVerifier hostnameVerifier = org.apache.http.conn.ssl.SSLSocketFactory.STRICT_HOSTNAME_VERIFIER;
       
        URL u = new URL(urlAddress);
        HttpsURLConnection urlConnection = (HttpsURLConnection) u.openConnection();
        urlConnection.setSSLSocketFactory(ssl_context.getSocketFactory());
        urlConnection.setHostnameVerifier(hostnameVerifier);
        urlConnection.connect();
       
        return (InputStream)urlConnection.getInputStream(); 
    }

    private static KeyStore loadClientKeyStore(Context context) throws KeyStoreException, NoSuchAlgorithmException, CertificateException, IOException {
            InputStream in =  context.getResources().openRawResource(R.raw.mykeystore);
            KeyStore trusted = null;
            trusted = KeyStore.getInstance("BKS");
            trusted.load(in, "mysecret".toCharArray());
            in.close();
            return trusted;
    }

Eclipse & maven setup for android development

I am using ubuntu. So developers of windows or mac should Google respective  softwares for their platforms.


1) Download latest an Eclipse.(I prefer Helios)
2) Download Android sdk.
3) Install ADT plugin in your eclipse follow this link.

4) Install maven using terminal

• wget http://mirror.olnevhost.net/pub/apache/maven/binaries/apache-maven-3.0.4-bin.tar.gz
• Run command above from the dir you want to extract maven to (e.g. /usr/local/apache-maven)
• tar xvf apache-maven-3.0.4-bin.tar.gz
• Export maven path:
export M2_HOME=/usr/local/apache-maven/apache-maven-3.0.4
export M2=$M2_HOME/bin
export PATH=$M2:$PATH
• Verify
mvn -version

   
 5) Install M2e plugin (maven integration for eclipse)

 5.1) Go Window -> preferences > choose Maven from left menu -> Installations
       -> Add the path of installed folder form maven (you did in step 4)

5.2) Now in same menu select User settings and then browse path of maven you installed in step 4 and select cofig/settings.xml (i.e /usr/share/maven/conf/settings.xml)

6) Install Android configrator for m2e (From eclipse market place)
(Open help -> eclipse marketplace.. -> search for this plugin)

7) Select window -> Preferences -> Archetypes --> Add local catelog
   and add this  file  from your machine

Thats all you configuration for maven and eclipse of complete