Cross App

Navigation out of your app and into another Fiori app, and back. This is the launchpad's own navigation, not abap2UI5's: it goes through the FLP shell, so the launchpad's history, its back button and its app-to-app contract all keep working. Inner App is the other direction — calling one of your own abap2UI5 classes, which never leaves the page and which the launchpad never hears about.

It only applies inside a launchpad. An abap2UI5 app served on its own has no shell to navigate through; see Fiori Launchpad for how an app gets there in the first place.

Am I in a Launchpad?

client->get( )-check_launchpad_active answers it, which is what guards everything on this page:

IF client->get( )-check_launchpad_active = abap_true.
  " the shell is there - cross-app navigation is available
ENDIF.

Navigating to Another App

Fire cross_app_nav_to_ext with the target intent — a semantic object and an action, exactly as a Fiori app would — and, optionally, parameters. Do not route this through a backend roundtrip: the shell has to do the navigating, or the launchpad's history and back button lose track of where the user is.

)->tag( `Button`
    )->a( n = `text`  v = `go to app 128`
    )->a( n = `press` v = client->follow_up_action(
              val   = client->cs_event-cross_app_nav_to_ext
              t_arg = VALUE #(
                  ( `{ semanticObject: "Z2UI5_CL_LP_SAMPLE_04", action: "display" }` )
                  ( `$` && client->_bind( nav_params ) ) ) )

The second argument carries the parameters. Binding a structure to it (rather than writing the values into the string) means the parameters are read from the model at press time, so they are whatever the user has just entered.

To go back to the launchpad app the user came from:

)->tag( `Button`
    )->a( n = `text`  v = `BACK`
    )->a( n = `press` v = client->follow_up_action( client->cs_event-cross_app_nav_to_prev_app )

Both are ordinary frontend events, so they work in the two positions every frontend event does: wired to a control as above, or as a statement in main when the navigation should follow some backend work. The arguments differ between the two, though. The object literal and the $ binding above are resolved by UI5 when the press fires; a statement sends its arguments as data, so there the target has to be JSON, {"semanticObject":"Z2UI5_CL_LP_SAMPLE_04","action":"display"}, and the parameters a JSON object of their values.

Which Apps Can I Navigate To?

cross_app_nav_get_links asks the shell for the intents the launchpad offers this user for a semantic object — the list a Fiori elements smart link shows in its popover — and hands the answer back as a backend event. t_arg is the target, the parameters and the event name; target and parameters are read like those of cross_app_nav_to_ext, an action in the target narrows the list, and the parameters drop the intents a mandatory parameter of which is missing:

client->follow_up_action(
    val   = client->cs_event-cross_app_nav_get_links
    t_arg = VALUE #( ( `{"semanticObject":"BusinessPartner"}` )
                     ( `{"BusinessPartner":"4711"}` )
                     ( `LINKS` ) ) ).

The event is raised once the shell has answered, its first argument a JSON array with one object per intent — intent (the hash), text, subTitle, and the hash split into semanticObject, action and params, ready to be handed to cross_app_nav_to_ext. Outside the launchpad the call is a logged no-op and the event is not raised, so a handler that waits for LINKS must not be the only way forward.

Arriving From Another App

Parameters from the target mapping — or from the start URL — arrive as name/value pairs:

DATA(lt_params) = client->get( )-t_comp_params.
DATA(lv_product) = VALUE #( lt_params[ n = `PRODUCT` ]-v OPTIONAL ).

Read them in the check_on_init( ) branch: they describe the start of the app instance, and they do not change over its life.

Setting the Shell Title

The launchpad shell has its own title bar, and the app can write it at any point in its life:

client->follow_up_action(
    val   = z2ui5_if_client=>cs_event-set_title_launchpad
    t_arg = VALUE #( ( `Invoice 4711` ) ) ).

set_title writes the browser tab instead — see Title. Inside a launchpad you usually want both, and they are two calls.

Working Samples

Complete apps from the sample catalog that use what this page describes. Each is a single class in abap2UI5/samples unless its row names another of the three sample repositories — pull that repository with abapGit and start the class with ?app_start=<class>.

Sample	Class
Cross-App Navigation Sender — hands two values over to another tile	Z2UI5_CL_SMPS_APP_483 · samples-stack, branch 09-launchpad
Cross-App Navigation Receiver — reads them back out of its startup parameters	Z2UI5_CL_SMPS_APP_484 · samples-stack, branch 09-launchpad
Read Startup Parameters — what the tile passed in - client->get( )-t_comp_params	Z2UI5_CL_SMPS_APP_481 · samples-stack, branch 09-launchpad