Просматривая исходный код приложения MailWidget (http://android.sopht.ca/), Я нашел способ. Однако я не думаю, что он задокументирован:
public class MessageReceiver extends BroadcastReceiver {
public static final Uri k9Uri = Uri.parse("content://com.fsck.k9.messageprovider/inbox_messages/");
static String[] messages_projection = new String[] {
"_id",
"date",
"sender",
"subject",
"preview",
"account",
"uri",
"delUri"
};
@Override
public void onReceive(Context context, Intent intent) {
Cursor curSt = mContext.getContentResolver().query(k9Uri, messages_projection, null, null, null);
curSt.moveToFirst();
String preview = curSt.getString(curSt.getColumnIndex("preview"));
}
}