HandleCommandL() on ui.cpp and view.cpp , a lil bit confuse.. HELP!!

this is in settingexampleui.cpp file

void CSettingExampleAppUi::HandleCommandL(TInt aCommand)
    {
    switch(aCommand)
        {
		case EAknSoftkeyExit:	// only softkey handled at this level
            Exit();
            break;
        default:
            break;
        }
    }

this is from the settingListView.cpp file

void CSettingListView::HandleCommandL(TInt aCommand)
    {
	switch(aCommand)
		{
	case ESettingCmdEdit :					// edit current item
		iSettingList->EditCurrentItemL();
		break;
	default :								// anything else
		AppUi()->HandleCommandL(aCommand);	// handled by AppUi
		break;
		}
	}

my question is what's difference between the two.. i understand that this two
classes handles command.. but what's the difference .. thanks.. help would much
be appreciated..THANK YOU!!..