OpenBackground

A Message sent to all background groups when a card they are placed on is opened. If there is a message handler by the same name in the message path, then it will be executed.

Message

Syntax:

openBackground <backgroundID>

The parameter <backgroundID> is the ID number of the background being opened.

The openBackground message is sent after the destination card is visible. To make changes that take effect before the card becomes visible on the screen, use the preOpenBackground message instead.

The actual navigation is not triggered by the openBackground message, so trapping the message and not allowing it to pass does not prevent the card with the group from opening.

Message handler

Examples:

on openBackground theBackgroundID
  -- update content of group
end openBackground

on openBackground theBackgroundID
   if the short name of this card is "highscores" then
      show button "play again"
   end if
end openBackground

Use the openBackground Message handler to change a group's objects, or perform other updates, when a card with the group on it is opened.

The openBackground message is sent to background groups, if there is more than one group on the card, the openBackground message is sent to each one.

A group is only considered a background group if its backgroundBehavior property is set to true.

See also: preOpenBackground, openCard, startup, newBackground, closeBackground, openStack, backgroundBehavior.