Creating Entry List Screenlet's Screenlet Class

Recall that when using a Screenlet, the app developer primarily interacts with its Screenlet class. The Screenlet class contains attributes for configuring the Screenlet’s behavior, a reference to the Screenlet’s View, methods for invoking Interactor operations, and more. This article shows you how to create Entry List Screenlet’s Screenlet class.

As with most of Entry List Screenlet, its Screenlet class is almost identical to that of Guestbook List Screenlet. Besides working with entries instead of guestbooks, the only difference is that it must know its entries’ guestbook ID. Even the Screenlets’ attributes are the same.

Therefore, this article doesn’t explain all the code in detail. Focus is instead placed on the few parts that differ from Guestbook List Screenlet. For a full explanation of the code, click here to see the article on creating Guestbook List Screenlet’s Screenlet class.

You’ll create Entry List Screenlet’s class with the same steps you used to create Guestbook List Screenlet’s class:

1. Define the Screenlet’s attributes. These are the XML attributes the app developer can set when inserting the Screenlet’s XML. These attributes control aspects of the Screenlet’s behavior.

2. Create the Screenlet class. This class implements the Screenlet’s functionality defined in the View and Interactor. It also reads the attribute values and configures the Screenlet accordingly.

First, you’ll define Entry List Screenlet’s attributes.

Defining Screenlet Attributes

Recall that before creating the Screenlet class, you must define the attributes the app developer needs to control the Screenlet’s behavior. Entry List Screenlet, like Guestbook List Screenlet, only needs a groupId attribute. In your app’s res/values directory, create entry_attrs.xml and replace its contents with this code:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="EntryListScreenlet">
        <attr name="groupId"/>
    </declare-styleable>
</resources>

Next, you’ll create the Screenlet class.

Creating the Screenlet Class

Entry List Screenlet’s class must contain an instance variable for the ID of the guestbook the Screenlet retrieves entries from. This is required to start the Interactor. This is the only significant difference between the Screenlet classes of Entry List Screenlet and Guestbook List Screenlet. The remaining differences exist only because they handle different entities.

Create the EntryListScreenlet class in the entrylistscreenlet package. Replace the class’s content with this code:

package com.liferay.docs.entrylistscreenlet;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.View;

import com.liferay.docs.entrylistscreenlet.interactor.EntryListInteractor;
import com.liferay.docs.liferayguestbook.R;
import com.liferay.docs.model.EntryModel;
import com.liferay.mobile.screens.base.list.BaseListScreenlet;
import com.liferay.mobile.screens.context.LiferayServerContext;

public class EntryListScreenlet extends BaseListScreenlet<EntryModel, EntryListInteractor> {

    private long guestbookId;

    public EntryListScreenlet(Context context) {
        super(context);
    }

    public EntryListScreenlet(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public EntryListScreenlet(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public EntryListScreenlet(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public void error(Exception e, String userAction) {
        if (getListener() != null) {
            getListener().error(e, userAction);
        }
    }

    @Override
    protected View createScreenletView(Context context, AttributeSet attributes) {
        TypedArray typedArray = context.getTheme().obtainStyledAttributes(attributes,
            R.styleable.GuestbookListScreenlet, 0, 0);
        groupId = typedArray.getInt(R.styleable.GuestbookListScreenlet_groupId,
            (int) LiferayServerContext.getGroupId());
        typedArray.recycle();

        return super.createScreenletView(context, attributes);
    }

    @Override
    protected void loadRows(EntryListInteractor interactor) {
        interactor.start(guestbookId);
    }

    @Override
    protected EntryListInteractor createInteractor(String actionName) {
        return new EntryListInteractor();
    }

    public long getGuestbookId() {
        return guestbookId;
    }

    public void setGuestbookId(long guestbookId) {
        this.guestbookId = guestbookId;
    }
}

The instance variable for the guestbook ID is guestbookId. The getter and setter methods getGuestbookId and setGuestbookId let the app developer get and set this variable, respectively. The loadRows method starts the Interactor by calling the start method with guestbookId as an argument. Behind the scenes, the list Screenlet framework passes guestbookId to the Interactor’s getPageRowsRequest and getPageRowCountRequest methods via the args argument. This is why you were able to extract guestbookId from the args argument in these methods. For an explanation of how the rest of this Screenlet class works, click here to see the article on creating Guestbook List Screenlet’s Screenlet class.

That’s it! Now you’re ready to use Entry List Screenlet alongside Guestbook List Screenlet. The following section of this Learning Path concludes with both Screenlets working together in harmony.