[Seaside] Re: Modal dialogs that appear with their "background"

[Stephan Eggermont]

EstebanAM wrote:
>I normally find/feel QCMagritte has a lot of things I could use, but 
>with scarce documentation it is really difficult to me to know where 
>to start with. 

Good point. We'll try to put something together.

>Would you provide a simple example of how to replace #call:/show: with 
>announcements? 

In the meantime you can take a look at StoryBoard, that does exactly the same
but then with Deltawerken.

That is exactly what the pagechoice components do. they have a collection of pages they
can show and switch when sent an announcement.

When initializing a component, we define the announcements that it should react to
by showing something different. In the homepage of storyboard, we by default
show the SBProjectOverview. SBProjectOverview has a method that announces 
SBProjectTonen (show project), that will result in an SBProjectDashboard being
shown on a project.

In SBHomePage (a subclass of DEPagechoice) we have

SBHomePage>>initialize
	super initialize.
	self homepage: SBProjectOverview new;
		goHomeOn: SBProjectOverviewTonen;
		goHomeOn: DELoggedIn;
		yourself.
	self addPage: SBProjectStoryBoard new
		announcement: SBProjectTonen
		symbol: #project.
	self addPage: SBProjectTeamPage new
		announcement: SBProjectTeamWijzigen
		symbol: #project.
	self addPage: SBProjectDashboard new
		announcement: SBProjectDashboardTonen
		symbol: #project.
	self addPage: SBUsersView new
		announcement: SBBeheerTonen		

so that reacts to
  SBProjectOverviewTonen, DELoggedIn, SBProjectTonen,
  SBProjectTeamWijzigen, SBProjectDashboardTonen and
  SBBeheerTonen.

By showing a different component.

To make that work, we have

DEPageChoice>>goHomeOn: announcement 
	self announcer 
		subscribe: announcement
		do: [ :ann | self currentPage: homepage ]

DEPageChoice>>addPage: page announcement: announcement symbol: aSymbol
	self addPage: page.
	self announcer
		subscribe: announcement
		do: [ :ann |
			(ann perform: aSymbol) ifNotNil: [ page subject: (ann perform: aSymbol) ].
			self currentPage: page]

DEPageChoice>>addPage: page announcement: announcement
	self addPage: page.
	self announcer
		subscribe: announcement
		do: [ :ann | 
			self currentPage: page.
		]

DEPageChoice>>addPage: page
	self pages 
		detect: [ :each | each = page ]
		ifNone: [ self pages add: page ].
	currentPage ifNil: [ currentPage := page ].
	^page

DEPageChoice>>renderContentOn: canvas
	currentPage 
		ifNil:  [ canvas text: 'Internal error in ', self class name ,': no current page set.' ]
		ifNotNil: [ canvas render: currentPage ]

The announcer comes from the superclass of DEPageChoice, DEComponent

DEComponent>>announcer
	^self session announcer

To make that work you need a session with an Announcer

DESession>>announcer
	^announcer ifNil: [ announcer := Announcer new ]


The project overview can then do the announcement to make the
homepage switch what page it shows. 

SBProjectOverview>>showProject: aProject
	self announce: (SBProjectTonen on: aProject)

SBProjectOverview >>showBeheer
	((self user class = SBAdministrator ) and: [self isLoggedIn]) ifTrue: [ 
		self announce: SBBeheerTonen]