Using the Framework for Your Application

The Screen Navigation Framework comprises two parts: Java classes for your screens and a tag library for your front-end. First you’ll create the necessary Java classes and then add the front-end support through JSPs.

Adding Screens to Your Application’s Back-end

You must create at least one Navigation Category. To add screens to your application, first you must add at least one Navigation Category for the top level navigation. Then you can add additional Navigation Entries for each page that you need.

First, add a Navigation Category

1. Create a component that implements the ScreenNavigationCategory interface.

2. Implement the following methods in your component:

   getCategoryKey(): returns the category’s primary key.

   getLabel(Locale locale): returns the label of the key.

   getScreenNavigationKey(): returns the navigation key that the category belongs in, as defined in your application.

Next, add a Navigation Entry.

1. Create a component which implements ScreenNavigationEntry.

2. Implement the following methods in your component:

   getCategoryKey(): returns the category’s primary key.

   getEntryKey(): returns the entry’s primary key.

   getLabel(): returns the entries label.

   getScreenNavigationKey(): returns the navigation key for the category of the current entry.

   isVisible(User user, T screenModelBean): boolean for whether or not the entry should be visible for the current user.

   render(HttpServletRequest request, HttpServletResponse response): renders the entry.

You can implement your render method any way that you want as long as it provides a way to render HTML. Liferay developers typically use JSPs, shown below.

Adding Screens to Your Application’s Front-end

To use JSPs to render your screens, you must invoke the JSPRenderer component in your render method and create the JSP that renders the HTML.

1. Create a render method which uses JSPRenderer like this:

   @Override
   public void render(HttpServletRequest request, HttpServletResponse response)
   throws IOException {
   
       _jspRenderer.renderJSP(request, response, "/my-category/view-category.jsp");
   }
   

2. Add the following code at the bottom of your class to use the reference annotation to access the JSPRenderer:

   @Reference
   private JSPRenderer _jspRenderer;
   

3. Create a JSP that includes the liferay-frontend:screen-navigation taglib and the necessary parameters like this:

   <liferay-frontend:screen-navigation key=
   "<%= AssetCategoriesConstants.CATEGORY_KEY_GENERAL %>"
   modelBean="<%= category %>"
   portletURL="<%= portletURL %>"
   />
   

The parameters it needs are key, modelBean, and portletURL.

• Key: a unique name for the navigation in this application.

• modelBean: the model that is being rendered

• portletURL: the portlet URL used to build the titles for each link.

In the next section, you’ll see how to extend an existing Liferay class with more screens.