Comment List Screenlet for Android

Requirements

• Android SDK 4.1 (API Level 16) or above
• Liferay Portal 6.2 CE/EE, Liferay CE Portal 7.0/7.1, Liferay DXP 7.0+
• Liferay Screens Compatibility app (CE or EE/DXP). This app is preinstalled in Liferay CE Portal 7.0/7.1 and Liferay DXP 7.0+.

Compatibility

• Android SDK 4.1 (API Level 16) or above

Xamarin Requirements

• Visual Studio 7.2
• Mono .NET framework 5.4.1.6

Features

Comment List Screenlet can list all the comments of an asset in a Liferay instance. It also lets the user update or delete comments.

JSON Services Used

Screenlets in Liferay Screens call JSON web services in the portal. This Screenlet calls the following services and methods.

Service	Method	Notes
ScreenscommentService (Screens compatibility plugin)	getComments
ScreenscommentService (Screens compatibility plugin)	getCommentsCount

Module

• None

Views

• Default

The Default View uses an Android RecyclerView to show an asset’s comments. Other Views may use a different component, such as TableView or others, to show the items.

Figure 1: Comment List Screenlet using the Default View.

Offline

This Screenlet supports offline mode so it can function without a network connection. For more information on how offline mode works, see the tutorial on its architecture. Here are the offline mode policies that you can use with this Screenlet:

Policy	What happens	When to use
REMOTE_ONLY	The Screenlet loads the comments from the Liferay instance. If a connection issue occurs, the Screenlet uses the listener to notify the developer about the error. If the Screenlet successfully loads the comments, it stores the data in the local cache for later use.	Use this policy when you always need to show updated data, and show nothing when there’s no connection.
CACHE_ONLY	The Screenlet loads the comments from the local cache. If the data isn’t there, the Screenlet uses the listener to notify the developer about the error.	Use this policy when you always need to show local data, without retrieving remote information under any circumstance.
REMOTE_FIRST	The Screenlet loads the comments from the Liferay instance. If this succeeds, the Screenlet shows the data to the user and stores it in the local cache for later use. If a connection issue occurs, the Screenlet retrieves the data from the local cache. If the data doesn’t exist there, the Screenlet uses the listener to notify the developer about the error.	Use this policy to show the most recent version of the data when connected, but show an outdated version when there’s no connection.
CACHE_FIRST	The Screenlet loads the comments from the local cache. If the data isn’t there, the Screenlet requests it from the Liferay instance and notifies the developer about any errors that occur (including connectivity errors).	Use this policy to save bandwidth and loading time in case you have local (but probably outdated) data.

Required Attributes

• className
• classPK

Attributes

Attribute	Data type	Explanation
layoutId	@layout	The layout to use to show the View.
autoLoad	boolean	Whether the list should automatically load when the Screenlet appears in the app’s UI. The default value is true.
cachePolicy	string	The offline mode setting. See the Offline section for details.
className	string	The asset’s fully qualified class name. For example, a blog entry’s className is com.liferay.blogs.kernel.model.BlogsEntry. The className and classPK attributes are required to instantiate the Screenlet.
classPK	number	The asset’s unique identifier. The className and classPK attributes are required to instantiate the Screenlet.
firstPageSize	number	The number of items to retrieve from the server for display on the first page. The default value is 50.
pageSize	number	The number of items to retrieve from the server for display on the second and subsequent pages. The default value is 25.
labelFields	string	The comma-separated names of the DDL fields to show. Refer to the list’s data definition to find the field names. For more information on this, see the article on structured web content. Note that the appearance of data from a structure’s fields depends on the layoutId.
editable	boolean	Whether the user can edit the comment.

Methods

Method	Return	Explanation
loadPage(pageNumber)	void	Starts the request to load the specified page of records. The page is shown when the response is received.

Listener

Comment List Screenlet delegates some events to a class that implements CommentListListener. This interface lets you implement the following methods:

• onDeleteCommentSuccess(CommentEntry commentEntry): Called when the Screenlet successfully deletes the comment.

• onUpdateCommentSuccess(CommentEntry commentEntry): Called when the Screenlet successfully updates the comment.

• onListPageFailed(int startRow, Exception e): Called when the server call to retrieve a page of items fails. This method’s arguments include the Exception generated when the server call fails.

• onListPageReceived(int startRow, int endRow, List<CommentEntry> entries, int rowCount): Called when the server call to retrieve a page of items succeeds. Note that this method may be called more than once; once for each page received. Because startRow and endRow change for each page, a startRow of 0 corresponds to the first item on the first page.

• onListItemSelected(CommentEntry element, View view): Called when an item is selected in the list. This method’s arguments include the selected list item (CommentEntry).

• error(Exception e, String userAction): Called when an error occurs in the process. The userAction argument distinguishes the specific action in which the error occurred.