Blaine Buxton: Positronic Vibrations From Alto Dorado

I got the following comment from Günther regarding this previous discussion:

Blaine,

I tried to get this to work with Menus and ContextMenus in the ViewComposer, without success.

Could you give us a for dummies description how to do that?

Thanks,

Günther, guenni

OK,
I've been writing a little utility for myself to manage my Mp3s in Dolphin and here's the code that I use to add commands to a context menu (when you right-click on a model object in a tree view):

setContextMenuFor: aModel 
 | menu |
 menu := aModel isNil
  ifTrue: [nil]
  ifFalse: 
   [| contextMenu |
    contextMenu := Menu description: 'IRiver'.
    aModel actionItemDescriptions do: 
    [:each | | command description |
     command := each key.
     description := each value.
     contextMenu 
     addCommand: command
     description: description].
    contextMenu].
 self tree view contextMenu: menu

The interesting bit of this method happens in #addCommand:description:. The command argument can be anything that understands the protocol #queryCommand: and #value. Symbol and MessageSend both do as well as my CommandMessageSend that I discussed earlier (since it is a subclass of MessageSend). Here's some examples of #actionItemDescriptions implementations that are called on the model in the above code:

Mp3Respository>>actionItemDescriptions
 | result |
 result := super actionItemDescriptions.
 result
  add: (CommandMessageSend receiver: self selector: #syncBackup) -> 'Sync Backup'.
 ^result

Mp3Root>>actionItemDescriptions
 | result |
 result := super actionItemDescriptions.
 result
  add: (MessageSend receiver: self selector: #save) -> 'Save'.
 ^result

I tried doing it through the ViewComposer and it can be done, but it's more trouble than it's worth. I decided to generate the code dynamically if I needed it. It's just as easy to add it through the code as it is to add it via the ViewComposer. I hope this explanation helps. I was trying out to see how I liked the model answering the things that it could do without knowing about the GUI. This was a cut at what it would feel like. Feel free to email me! =) I'll try to get on the IRC discussion more often.

posted by Blaine at 9:24 PM |  1 comments |  Post a Comment