Android Services

Android Services

A Service is an application component that can perform long-running operations in the background and does not provide a user interface. 

• Another application component can start a service and it will continue to run in the background even if the user switches to another application. 
• Additionally, a component can bind to a service to interact with it and even perform interprocess communication (IPC). 
• For example, a service might handle network transactions, play music, perform file I/O, or interact with a content provider, all from the background

Detailed documentation on services can be found from Google Android Services Documentation

Other examples and articles on Android Services:

• http://www.vogella.com/articles/AndroidServices/article.html
• Services example from Marakana
• http://saigeethamn.blogspot.com/2009/09/android-developer-tutorial-for_04.html

Services Lifecycle Diagram from developer.android.com:

Android Data Storage

Android Data Storage

Android provides several ways to store the data. More details can be found from http://developer.android.com/guide/topics/data/data-storage.html

• Shared Preferences
• This provides a quick and easy way to store key-value pair based primitive data across multiple sessions of the app; DOES NOT preserve the data across power cycle.
• Examples/Tutorials
• http://www.vogella.com/articles/AndroidFileBasedPersistence/article.html
• Internal Storage
• Stores the data on the internal storage of the phone. Preserves the data across the power cycles.
• Files created gets removed when the user uninstalls the app
• This data is app-specific data; Not world readable
• E.g. Example of Internal Storage on Android
• External Storage (e.g. SD Card)
• This is saved/restored in similar way as the internal storage
• HOWEVER -- IT IS WORLD READABLE; So do not save sensitive data
• E.g. External Storage example on Android
• SQLite Databases
• Android has full support for SQLite
• Any database created in the app, can be accessed by the name from any class in the app
• Not outside the app
• To Create a new database, create a subclass of SQLiteOpenHelper
• E.g. 
• http://www.vogella.com/articles/AndroidSQLite/article.html
• http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/
• Cloud storage
• 
  
• Content provider
• It is the only way to share the data across multiple apps - selectively
• Content provider and Content resolver provides an interface to the app to talk to the Contents, which could be SQLite database or Internal/External storage or on cloud
• Managed Queries is another important concept to understand with ContentProvider with the queries; Managed Queries based cursor will get updated automatically as and when the activity goes through it's life cycle
• Good Blog: http://www.vogella.com/articles/AndroidSQLite/article.html#contentprovider

Android Intents

Android Intents

• Good article on Android Intents - http://www.vogella.com/articles/AndroidIntent/article.html
• Google documentation - http://developer.android.com/guide/components/intents-filters.html
• Few more articles/Videos
• http://www.androiduipatterns.com/2011/06/android-intents-apps-talking-to-each.html
• Videos on android Intent: 
• http://www.youtube.com/watch?v=lqopIf-bA54
• http://www.youtube.com/watch?v=cv2bh53IL_Y
• 
  

Android Basics

Android Basics

In this blog, I am trying to list some android basics including the details about the android architecture

• What is android
• Android Architecture

Android Devp

Developing Android Applications

When I started learning android development a couple of years ago, the web resources like blogs and youtube videos were the most handy resources for me to quickly find answers to my howtos! However, I still had to spend great amount of time to pick and choose what is more relavant. In this always work-in-progress blog, I am trying to list as many howtos as I can - which could come handy while working on android development

Refer to my another blog on how to setup the android app devp env to start with HelloAndroid app: http://myz2sky.blogspot.com/2012/06/android-development-using-eclipse.html

Check my github for the example apps and some useful links on it's wiki - https://github.com/ddesai/