Android content providers'-content providers' BASICS (Contract class ))

Contract class)

The contract class defines some features that use content resource identifiers (URIs), column names, intent actions, and content providers to help applicationsProgramA constant of work. Contract classes are not automatically included with providers. providers must define them and make them valid for other developers. The Android platform contains many providers' corresponding contract classes in the Android. provider package.

For example, the user dictionary provides a contract class that contains the content resource identifier (URI) and column name constants. The content resource ID for the "Words" table is defined in the constant userdictionary. wordscontent_uri. The userdictionary. Words class also contains column name constants used in this example. For example, the query projection can be defined as follows:

String [] mprojection =
{
Userdictionary. Words. _ id,
Userdictionary. Words. Word,
Userdictionary. Words. locale
};

Another contract class is the contactscontract class of the Communication record provider. One of its subclasses, contactscontract. intents. insert is a contract class that contains constants for intent objects and intent data.