Programming Android

Chapter 12. Using Content Providers

When Android applications share data, they rely on the content provider API to expose data within their database. For example, the Android contact content provider allows an unlimited number of applications to reuse contact persistence on the Android platform. By simply invoking this content provider, an application can integrate access to a user’s contacts stored locally and synchronized with the Google cloud. Applications can read and write data in content providers without having to provide their own database manipulation code. In this way, content providers provide a powerful feature that allows developers to easily create applications with sophisticated data management—in many cases, applications will end up writing very little data persistence code of their own.

The content provider API enables client applications to query the OS for relevant data using a Uniform Resource Identifier (URI), similar to the way a browser requests information from the Internet. For a given URI query, a client does not know which application will provide the data; it simply presents the OS with a URI and leaves it to the platform to start the appropriate application to provide the result. The platform also provides a permission that allows clients to limit access to content provider data.

The content provider API enables full create, read, update, and delete access to shared content. This means applications can use URI-oriented requests to:

• Create new records

• Retrieve ...