DDL 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

The DDL List Screenlet has the following features:

• Shows a scrollable collection of Dynamic Data List (DDL) records.
• Implements fluent pagination with configurable page size.
• Allows record filtering by creator.
• Supports i18n in record values.

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
ScreensddlrecordService (Screens compatibility plugin)	getDdlRecords	With ddlRecordSetId, or ddlRecordSetId and userId
ScreensddlrecordService (Screens compatibility plugin)	getDdlRecordsCount

Module

• DDL

Views

• Default
• Material

The Default View uses a standard RecyclerView to show the scrollable list. Other Views may use a different component, such as ViewPager or others, to show the items.

Portal Configuration

DDLs and Data Types should be configured in the portal before using DDL List Screenlet. For more details, see the Liferay User Guide sections Creating Data Definitions and Creating Data Lists .

Also, to allow remote calls without the userId, the Liferay Screens Compatibility app must be installed in your Liferay instance. You can find this app on Liferay Marketplace.

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.

Policy	What happens	When to use
REMOTE_ONLY	The Screenlet loads the list from the portal. If a connection issue occurs, the Screenlet uses the listener to notify the developer about the error. If the Screenlet successfully loads the list, 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 list from the local cache. If the list 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 list from the portal. If this succeeds, the Screenlet shows the list to the user and stores it in the local cache for later use. If a connection issue occurs, the Screenlet retrieves the list from the local cache. If the list 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 list from the local cache. If the list isn’t there, the Screenlet requests it from the portal 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

• recordSetId
• labelFields

Attributes

Attribute	Data type	Explanation
layoutId	@layout	The layout to use to show the View.
autoLoad	boolean	Defines whether the list should be loaded when it’s presented on the screen. The default value is true.
recordSetId	number	The ID of the DDL being called. To find your DDLs’ IDs, click Admin → Content from the Dockbar. Then click Dynamic Data Lists on the left. Each DDL’s ID is in the ID column of the table.
userId	number	The ID of the user to filter records on. Records aren’t filtered if the userId is 0. The default value is 0.
cachePolicy	string	The offline mode setting. See the Offline section for details.
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 Creating Data Definitions. Note that the appearance of these values in your app depends on the layoutId set.
obcClassName	string	The name of the OrderByComparator class to use to sort the results. Omit this property if you don’t want to sort the results. Click here to see some comparator classes. Note, however, that not all of these classes can be used with obcClassName. You can only use comparator classes that extend OrderByComparator<DDLRecord>. You can also create your own comparator classes that extend OrderByComparator<DDLRecord>.

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

DDL List Screenlet delegates some events to an object or a class that implements the BaseListListener interface. This interface lets you implement the following methods:

• 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<Record> records, 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(Record records, View view): Called when an item is selected in the list. This method’s arguments include the selected list item (Record).

• 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.