Is it possible to define a function to be called when a MenuItem is selected?

[Jonathan Ferguson]

Hello all, 

   I have a custom Loc in which I override supplimentalKidMenuItems to build a sub menu based on a database table.  Ideally when a MenuItem from the sub menu is clicked a function would be run allowing me to change state.  Currently I'm stuck and am thinking about using a RestHelper to trigger the state change, which seems ugly.

   override def supplimentalKidMenuItems =  CurrentUser.is match{

      case Full(u) =>

        val ts = u.things

        ts.size match {

          case 1 => Nil  

          case otherwise =>

            val x = for { t <- ts}  yield {MenuItem(Text(t.name.is), Text("switch/%s".format(t.id)), Nil, false, false,Nil)}

            x.toList ::: super.supplimentalKidMenuItems 

        }

      case otherwise => Nil

      }

Any pointers would be appreciated.

Thank you 

Jono

[David Whittaker]

Hi Jono,

What type of state are we talking about?  Does your code need to run when the menu item is clicked, or can it be invoked when the page the menu item points to is displayed?

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[Jonathan Ferguson]

Hi David, 

  

The code needs to run when the menu item is clicked. So the new state is available to the snippets when the page is being built. 

Jono

[David Whittaker]

Jono,

Could you not accomplish that through a type safe Loc that calculates a value?  Maybe this doesn't fit your particular use case but I'm thinking that a Loc[State] where the the State is calculated via a CalcValue LocParam would make the State available to the snippets when the Loc is matched.  You can then define your snippets as:

class MySnippet(val state: State) extends DispatchSnippet {

..... some transforms that use your state .....

[Jonathan Ferguson]

Hi David, 

Sorry for the delay, I got caught up with another project. 

I think this could be a viable solution. Do you know where there is anything documentation on type safe Loc and LocParam other than the scala docs?

I'll have a look at the scala doc and see if I can get an example working. 

Thank you 

Jono

[David Whittaker]

Hi Jono,

There is some info in Exploring Lift: http://exploring.liftweb.net/master/index-7.html#toc-Subsection-7.6.2 and HarryH from Foursquare put together some slides on how they use them a while back: https://docs.google.com/present/view?id=dcbpz3ck_38cj3kdbgm.  Hope that helps.

-Dave