Creating Entry List Screenlet's Interactor

Recall that list Screenlets require an Interactor to instantiate the Connector and receive the server call’s results. In this article, you’ll create Entry List Screenlet’s Interactor.

Because this Interactor is so similar to that of Guestbook List Screenlet, the steps to create it aren’t explained in detail. Focus is instead placed on the few places in the code where the Interactors diverge. For a full explanation of the code, see the article on creating Guestbook List Screenlet’s Interactor.

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 EntryListScreenlet folder.

  2. Drag and drop the Interactor folder from the Finder into your Xcode project, under the EntryListScreenlet 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.

Now you’re ready to create the Interactor.

Creating the Interactor

Recall that the Interactor class of a list Screenlet that implements fluent pagination must extend the BaseListPageLoadInteractor class. Your Interactor class must also contain any properties the Screenlet needs, and an initializer that sets them. This initializer also 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 Entry List Screenlet’s Interactor:

  1. In the Project navigator, right-click the Interactor folder you added above 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 EntryListPageLoadInteractor, 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. Replace the class file’s contents with this code:

    import UIKit
    import LiferayScreens
    
    class EntryListPageLoadInteractor: BaseListPageLoadInteractor {
    
        private let groupId: Int64
        private let guestbookId: Int64
    
        init(screenlet: BaseListScreenlet,
             page: Int,
             computeRowCount: Bool,
             groupId: Int64,
             guestbookId: Int64) {
    
            self.groupId = (groupId != 0) ? groupId : LiferayServerContext.groupId
            self.guestbookId = guestbookId
    
            super.init(screenlet: screenlet, page: page, computeRowCount: computeRowCount)
        }
    
        public override func createListPageConnector() -> PaginationLiferayConnector {
            let screenlet = self.screenlet as! BaseListScreenlet
    
            return EntryListPageLiferayConnector(
                startRow: screenlet.firstRowForPage(self.page),
                endRow: screenlet.firstRowForPage(self.page + 1),
                computeRowCount: self.computeRowCount,
                groupId: groupId,
                guestbookId: guestbookId)
        }
    
        override public func convertResult(_ serverResult: [String:AnyObject]) -> AnyObject {
    
            return EntryModel(attributes: serverResult)
        }
    
        override public func cacheKey(_ op: PaginationLiferayConnector) -> String {
            return "\(groupId)-\(guestbookId)"
        }
    
    }
    

    This class is almost identical to Guestbook List Screenlet’s Interactor, GuestbookListPageLoadInteractor. The only real difference is that EntryListPageLoadInteractor handles entries. It therefore needs a guestbookId variable to define the guestbook to retrieve entries from. This variable is set in the initializer and then used in the createListPageConnector method to create a EntryListPageLiferayConnector instance. The convertResult method receives each [String:AnyObject] entry from the server and transforms it into an EntryModel object. Also recall that the cacheKey method must return a key that can be used with online mode. For entries, a combination of the groupId and guestbookId is a sufficient key.

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

« Creating Entry List Screenlet's ConnectorCreating Entry List Screenlet's Delegate »
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