20040208: Displays for CompositeDataChoice

>From: "Paul Gifford" <address@hidden>
>Organization: independent
>Keywords: 200402090424.i194OFp1020301

Hi Paul-

>  I have CompositeDataChoices made up of DirectDataChoices.  These are
>displayed in tree fashion  in the Fields column in the Data selector as they
>should be.  When I click on a composite node (displayed as a folder), the
>Displays list if filled with every type of display possible.  How do I make
>that list empty?  Right now I'm passing null for the category list for the
>CompositeDataChoice constructor - I've tried lists with various items
>contained (and an empty list) but nothing worked.

A null DataCategory is the same as ANY.  I guess we need a NONE.  I'll
look into that.

What is the purpose of creating your CompositeData Choice?  If it's just
to group them all together, then you could use a DataCategory with the
first group being for display only.  This is what we do for the 
gridded data (i.e. 2D grids vs. 3D grids).

So, your code would look something like:

    List firstCategories = DataCategory.parseCategories("Group1;2D-GRID");
    List secondCategories = DataCategory.parseCategories("Group2;2D-GRID");
    DataChoice choice = null;
    for (int i = 0; i < numThings; i++) {
        if (thing[i] == firstType) {
           choice = new DirectDataChoice(this, name, name,
                                         description, firstCategories);
        } else {
           choice = new DirectDataChoice(this, name, name,
                                         description, secondCategories);
        }
        (do something with choice)
     }

or some such thing. ;-)  By default, parseCategories will make the first
category for display.

If this is not clear, let me know.

Don
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