Introduction to Android Development (20) content provider 20.3 predefined query string constants

In addition to using your own manual write query Uri, you can also use the built-in URI query constants for Android.

For example, in addition to using Content://contacts/people, you can write this assignment statement.

Uri allcontacts = ContactsContract.Contacts.CONTENT_URI;

Some of the built-in predefined query string constants for Android.

Browser.bookmarks_uri

Browser.searchs_uri

Calllog.content_uri

Mediasto Re. Images.Mdeia.INTERNAL_CONTENT_URI

MediaStore.Images.Media.EXTERNAL_CONTENT_URI

S ettings. Content_uri

If you want to query the first contact, you need to specify an ID.

Uri allcontacts = Uri.parse ("CONTENT://CONTACTS/PEOPLE/1");

You can also do this:

Uri allcontacts = Contenturis.withappendedid (ContactsContract.Contacts.CONTENT_URI, 1);

In addition to displaying the contact person in the ListView, you can also print it out.

private void Printcontacts (Cursor c) {  
    if (C.movetofirst ()) {do  
        {  
            String ContactID = c.getstring (c  
                    . Getcolumnindex (contactscontract.contacts._id));  
            String contactdisplayname = C  
                    . getString (c  
                            . Getcolumnindex (ContactsContract.Contacts.DISPLAY_NAME));  
            LOG.V ("Content Providers", ContactID + ","
                    + contactdisplayname);  
        } while (C.movetonext ());  
    }  
}