ComboBox - Validation

" @keywords combobox combo box sap.m comboboxvalidation verticallayout label item
" @summary The combo box control could be restricted to allow selection only from the items in the list.
CLASS z2ui5_cl_smpc_app_475 DEFINITION PUBLIC.

  PUBLIC SECTION.
    INTERFACES z2ui5_if_app.

    TYPES: BEGIN OF ty_s_country,
             key  TYPE string,
             text TYPE string,
           END OF ty_s_country.
    TYPES ty_t_country TYPE STANDARD TABLE OF ty_s_country WITH EMPTY KEY.

    DATA t_countries TYPE ty_t_country.

    DATA selected_key     TYPE string.
    DATA value            TYPE string.
    DATA value_state      TYPE string VALUE `None`.
    DATA value_state_text TYPE string.

  PROTECTED SECTION.
    DATA client TYPE REF TO z2ui5_if_client.

    METHODS view_display.
    METHODS on_event.
    METHODS model_init.

  PRIVATE SECTION.
ENDCLASS.


CLASS z2ui5_cl_smpc_app_475 IMPLEMENTATION.

  METHOD z2ui5_if_app~main.

    me->client = client.
    IF client->check_on_init( ).
      model_init( ).
      view_display( ).
    ELSEIF client->check_on_navigated( ).
      view_display( ).
    ELSEIF client->check_on_event( ).
      on_event( ).
    ENDIF.

  ENDMETHOD.


  METHOD view_display.

    DATA(view) = z2ui5_cl_ui5_view_builder=>factory( ).

    view->ele( n = `View` ns = `mvc`
        )->a( n = `height`     v = `100%`
        )->a( n = `xmlns:l`    v = `sap.ui.layout`
        )->a( n = `xmlns:core` v = `sap.ui.core`
        )->a( n = `xmlns:mvc`  v = `sap.ui.core.mvc`
        )->a( n = `xmlns`      v = `sap.m`

        )->ele( n = `VerticalLayout` ns = `l`
            )->a( n = `class` v = `sapUiContentPadding`
            )->a( n = `width` v = `100%`

            )->tag( `Label`
                )->a( n = `text`     v = `Choose a country:`
                )->a( n = `labelFor` v = `idComboBox`
            " handleChange validates in the controller - validation is business logic,
            " so it happens in ABAP and the two value-state properties are bound
            )->ele( `ComboBox`
                )->a( n = `id`             v = `idComboBox`
                )->a( n = `items`          v = |\{ path: '{ client->_bind_path( t_countries ) }', sorter: \{ path: 'TEXT' \} \}|
                )->a( n = `selectedKey`    v = client->_bind( selected_key )
                )->a( n = `value`          v = client->_bind( value )
                )->a( n = `valueState`     v = client->_bind( value_state )
                )->a( n = `valueStateText` v = client->_bind( value_state_text )
                )->a( n = `change`         v = client->_event( `CHANGE` )

                )->tag( n = `Item` ns = `core`
                    )->a( n = `text` v = `{TEXT}`
                    )->a( n = `key`  v = `{KEY}` ).

    client->view_display( view->stringify( ) ).

  ENDMETHOD.


  METHOD on_event.

    IF client->get_event( ) = `CHANGE`.

      " a typed value with no matching key is the error case of the original
      IF selected_key IS INITIAL AND value IS NOT INITIAL.
        value_state      = `Error`.
        value_state_text = `Please enter a valid country!`.
      ELSE.
        value_state      = `None`.
        CLEAR value_state_text.
      ENDIF.

    ENDIF.

  ENDMETHOD.


  METHOD model_init.

    " full mock /CountriesCollection of ui5/mock/countriesExtendedCollection.json
    t_countries = VALUE #(
        ( key = `DZ`  text = `Algeria` )
        ( key = `AR`  text = `Argentina` )
        ( key = `AU`  text = `Australia` )
        ( key = `AT`  text = `Austria` )
        ( key = `BH`  text = `Bahrain` )
        ( key = `BE`  text = `Belgium` )
        ( key = `BA`  text = `Bosnia and Herzegovina` )
        ( key = `BR`  text = `Brazil` )
        ( key = `BG`  text = `Bulgaria` )
        ( key = `CA`  text = `Canada` )
        ( key = `CL`  text = `Chile` )
        ( key = `CO`  text = `Colombia` )
        ( key = `HR`  text = `Croatia` )
        ( key = `CU`  text = `Cuba` )
        ( key = `CZ`  text = `Czech Republic` )
        ( key = `DK`  text = `Denmark` )
        ( key = `EG`  text = `Egypt` )
        ( key = `EE`  text = `Estonia` )
        ( key = `FI`  text = `Finland` )
        ( key = `FR`  text = `France` )
        ( key = `GER` text = `Germany` )
        ( key = `GH`  text = `Ghana` )
        ( key = `GR`  text = `Greece` )
        ( key = `HU`  text = `Hungary` )
        ( key = `IN`  text = `India` )
        ( key = `ID`  text = `Indonesia` )
        ( key = `IE`  text = `Ireland` )
        ( key = `IL`  text = `Israel` )
        ( key = `IT`  text = `Italy` )
        ( key = `JP`  text = `Japan` )
        ( key = `JO`  text = `Jordan` )
        ( key = `KE`  text = `Kenya` )
        ( key = `KW`  text = `Kuwait` )
        ( key = `LV`  text = `Latvia` )
        ( key = `LT`  text = `Lithuania` )
        ( key = `MK`  text = `Macedonia` )
        ( key = `MY`  text = `Malaysia` )
        ( key = `MX`  text = `Mexico` )
        ( key = `ME`  text = `Montenegro` )
        ( key = `MA`  text = `Morocco` )
        ( key = `NL`  text = `Netherlands` )
        ( key = `NZ`  text = `New Zealand` )
        ( key = `NG`  text = `Nigeria` )
        ( key = `NO`  text = `Norway` )
        ( key = `OM`  text = `Oman` )
        ( key = `PE`  text = `Peru` )
        ( key = `PH`  text = `Philippines` )
        ( key = `PL`  text = `Poland` )
        ( key = `PT`  text = `Portugal` )
        ( key = `QA`  text = `Qatar` )
        ( key = `RO`  text = `Romania` )
        ( key = `RU`  text = `Russia` )
        ( key = `SA`  text = `Saudi Arabia` )
        ( key = `SN`  text = `Senegal` )
        ( key = `RS`  text = `Serbia` )
        ( key = `SG`  text = `Singapore` )
        ( key = `SK`  text = `Slovakia` )
        ( key = `SI`  text = `Slovenia` )
        ( key = `ZA`  text = `South Africa` )
        ( key = `KR`  text = `South Korea` )
        ( key = `ES`  text = `Spain` )
        ( key = `SE`  text = `Sweden` )
        ( key = `CH`  text = `Switzerland` )
        ( key = `TN`  text = `Tunisia` )
        ( key = `TR`  text = `Turkey` )
        ( key = `UG`  text = `Uganda` )
        ( key = `UA`  text = `Ukraine` )
        ( key = `AE`  text = `United Arab Emirates` )
        ( key = `GB`  text = `United Kingdom` )
        ( key = `YE`  text = `Yemen` ) ).

  ENDMETHOD.

ENDCLASS.