Creating the iOS List Screenlet's Class

Now that your list Screenlet’s other components exist, you can create the Screenlet class. A list Screenlet’s Screenlet class must extend the BaseListScreenlet class and define the configurable properties the Screenlet needs. You should define these as IBInspectable properties. If you want to support offline mode, you should also add an offlinePolicy property.

For example, Bookmark List Screenlet’s Screenlet class contains the IBInspectable properties groupId, folderId, and offlinePolicy:

public class BookmarkListScreenlet: BaseListScreenlet {

    @IBInspectable public var groupId: Int64 = 0
    @IBInspectable public var folderId: Int64 = 0
    @IBInspectable public var offlinePolicy: String? = CacheStrategyType.RemoteFirst.rawValue

    ...

Next, override the createPageLoadInteractor method to create and return the Interactor. If your Screenlet supports offline mode, you should also use offlinePolicy to pass a CacheStrategyType object to the Interactor. For example, the createPageLoadInteractor method in BookmarkListScreenlet creates and returns a BookmarkListPageLoadInteractor instance. This method also sets the Interactor’s cacheStrategy property to a CacheStrategyType object created with offlinePolicy:

override public func createPageLoadInteractor(
    page page: Int, 
    computeRowCount: Bool) -> BaseListPageLoadInteractor {

    let interactor = BookmarkListPageLoadInteractor(screenlet: self,
                                                    page: page,
                                                    computeRowCount: computeRowCount,
                                                    groupId: self.groupId,
                                                    folderId: self.folderId)

    interactor.cacheStrategy = CacheStrategyType(rawValue: self.offlinePolicy ?? "") ?? .RemoteFirst

    return interactor
}

Now get a reference to your delegate. The BaseScreenlet class, which BaseListScreenlet extends, already defines the delegate property for the delegate object. Every list Screenlet therefore has this property, and any app developer using the Screenlet can access it. To avoid casting this property to your delegate every time you use it, add a computed property to your Screenlet class that does so. For example, the following bookmarkListDelegate property in BookmarkListScreenlet casts the delegate property to BookmarkListScreenletDelegate:

public var bookmarkListDelegate: BookmarkListScreenletDelegate? {
    return delegate as? BookmarkListScreenletDelegate
}

Next, override the BaseListScreenlet methods that handle the Screenlet’s events. Because these events correspond to the events your delegate methods handle, you’ll call your delegate methods in these BaseListScreenlet methods:

• onLoadPageResult: Called when the Screenlet loads a page successfully. Override this method to call your delegate’s screenlet(_:onBookmarkListResponse:) method. For example, here’s BookmarkListScreenlet’s onLoadPageResult method:

    override public func onLoadPageResult(page page: Int, rows: [AnyObject], rowCount: Int) {
        super.onLoadPageResult(page: page, rows: rows, rowCount: rowCount)
  
        bookmarkListDelegate?.screenlet?(screenlet: self, onBookmarkListResponse: rows as! [Bookmark])
    }
  

• onLoadPageError: Called when the Screenlet fails to load a page. Override this method to call your delegate’s screenlet(_:onBookmarkListError:) method. For example, here’s BookmarkListScreenlet’s onLoadPageError method:

    override public func onLoadPageError(page page: Int, error: NSError) {
        super.onLoadPageError(page: page, error: error)
  
        bookmarkListDelegate?.screenlet?(screenlet: self, onBookmarkListError: error)
    }
  

• onSelectedRow: Called when an item is selected in the list. Override this method to call your delegate’s screenlet(_:onBookmarkSelected:) method. For example, here’s BookmarkListScreenlet’s onSelectedRow method:

    override public func onSelectedRow(_ row: AnyObject) {
        bookmarkListDelegate?.screenlet?(screenlet: self, onBookmarkSelected: row as! Bookmark)
    }
  

« Creating the iOS List Screenlet's DelegateCreating iOS Themes »