abap2UI5

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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:

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

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.

abap
)->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:

abap
)->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.

Arriving From Another App ​

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

abap
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:

abap
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.