Recall from the basic Screenlet creation tutorial that the listener interface
defines a success method and a failure method. This lets implementing classes
respond to the server call’s success or failure. Listeners that support offline
mode offer the same functionality, although differently. Offline mode listeners
must extend BaseCacheListener, which defines only this error method:
void error(Exception e, String userAction);
By extending BaseCacheListener, your listener no longer needs an explicit
failure method because it inherits the error method instead. This error
method also includes an argument for the user action that triggered the
exception.
You can therefore update your listener to support offline mode by extending
BaseCacheListener and deleting the failure method. For example, here’s Add
Bookmark Screenlet’s listener, AddBookmarkListener, after being updated to
support offline mode:
public interface AddBookmarkListener extends BaseCacheListener {
onAddBookmarkSuccess();
}
Note that you must also remove any failure method implementations (such as in an
activity or fragment that implements the listener), and replace any failure
method calls with error method calls. You’ll do the latter next when updating
the Interactor class.