android interview questions -- Content Providers

Whats is content provider?

Content provider is a mechanism to share data between application. Android doesn't provide common area to store data , so this is the only mechanism to share data between applications.

Brief  about how data sharing mechanism works using content provider?

• Content provider should expose its URI to the applications.
• Application will send URI to the ContentResolver
• ContentResolver will send this published query to ContentProvider
• ContentProvider will send back requested data to ContentResolver(CR), In responce CR send this data to application.

How to query a content provider?

Android provides below methods to make a query

• ContentResolver.query()
• Activity.managedQuery()

What query methods return?

Cursor object.

What are the steps to implment our own ContentProvider?

• Plan DB, URI's ,Column Names ,Column Type etc.
• Populate DB
• Extend ContentProvider abstract class
• Implenet methods query(), insert(), delete(), getType(), update()
• Register CP through android manifest file.