Creating Guestbook List Screenlet's Interactor

Interactors implement your Screenlet’s actions. In non-list Screenlets, this can include making the server call. List Screenlets, however, make server calls via Connectors. Also, loading entities is usually the only action a user can take in a list Screenlet. Therefore, list Screenlet Interactors typically only need to instantiate the Connector and receive the server call’s results. This is the case for Guestbook List Screenlet’s Interactor. You’ll create this Interactor now.

Creating Your Interactor’s Folder

Follow these steps to create your Interactor’s folder:

  1. In the Finder, create the Interactor folder inside your project’s GuestbookListScreenlet folder.

  2. Drag and drop the Interactor folder from the Finder into your Xcode project, under the GuestbookListScreenlet folder. In the dialog that appears, select Copy items if needed, Create groups, and the Liferay Guestbook target. Then click Finish. The Interactor folder now appears in your project.

    Figure 1: The new Interactor folder should be inside the Screenlets folder.

    Figure 1: The new `Interactor` folder should be inside the Screenlet's folder.

Now you’re ready to create the Interactor.

Creating the Interactor

The Interactor class of a list Screenlet that implements fluent pagination must extend Liferay Screens’s BaseListPageLoadInteractor class. This class provides most of the functionality required by list Screenlet Interactors. Your Interactor class must also contain any properties your Screenlet needs and an initializer that sets them. This initializer needs arguments for the following properties, which it passes to the superclass initializer:

  • screenlet: A BaseListScreenlet reference. This ensures the Interactor always has a Screenlet reference.
  • page: The page number to retrieve.
  • computeRowCount: Whether to call the Connector’s doAddRowCountServiceCall method.

Follow these steps to create Guestbook List Screenlet’s Interactor:

  1. In the Project navigator, right-click the Interactor folder and select New File. In the dialog that appears, fill out each screen as follows:

    • Select iOSSourceCocoa Touch Class, and click Next.
    • Name the class GuestbookListPageLoadInteractor, set it to extend BaseListPageLoadInteractor, select Swift for the language, and click Next.
    • Make sure the Interactor folder and group is selected, as well as the Liferay Guestbook target (these should be selected by default). Click Create.
  2. In the new class, import LiferayScreens and add a private Int64 constant called groupId. This constant holds the ID of the site guestbooks are retrieved from. Your Interactor should now look like this:

    import UIKit
    import LiferayScreens
    class GuestbookListPageLoadInteractor: BaseListPageLoadInteractor {
        private let groupId: Int64
  3. Create an initializer that takes the arguments screenlet, page, computeRowCount, and groupId. In this initializer, set the groupId constant to the corresponding argument, then call the superclass initializer with the remaining arguments. Note that if the the groupId is 0, the groupId setting in liferay-server-context.plist is used instead. Add the initializer as follows:

    init(screenlet: BaseListScreenlet,
        page: Int,
        computeRowCount: Bool,
        groupId: Int64) {
        self.groupId = (groupId != 0) ? groupId : LiferayServerContext.groupId
        super.init(screenlet: screenlet, page: page, computeRowCount: computeRowCount)
  4. Override the createListPageConnector method to create and return an instance of your Connector, GuestbookListPageLiferayConnector. This method must first get a reference to the Screenlet via the screenlet property. When calling the Connector’s initializer, use screenlet.firstRowForPage to convert the page number (page) to the page’s start and end indices. You must also pass the initializer any other properties it needs, like groupId. Add this createListPageConnector method to your Interactor class:

    public override func createListPageConnector() -> PaginationLiferayConnector {
        let screenlet = self.screenlet as! BaseListScreenlet
        return GuestbookListPageLiferayConnector(
            startRow: screenlet.firstRowForPage(,
            endRow: screenlet.firstRowForPage( + 1),
            computeRowCount: self.computeRowCount,
            groupId: groupId)
  5. Override the convertResult method to convert each [String:AnyObject] result into a GuestbookModel object. The Screenlet calls this method once for each guestbook retrieved from the server. Add this method as follows:

    override public func convertResult(_ serverResult: [String:AnyObject]) -> AnyObject {
        return GuestbookModel(attributes: serverResult)
  6. Override the cacheKey method to return a key that can be used with offline mode. Although Guestbook List Screenlet won’t initially support offline mode, this method is still required. For this Screenlet, the groupId serves as a sufficient key. Add this method as follows:

    override public func cacheKey(_ op: PaginationLiferayConnector) -> String {
        return "\(groupId)"

Great! Your Interactor is finished. Next, you’ll create the delegate.

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