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From: kn@doc.ic.ac.uk (Keng Ng)
Newsgroups: comp.sys.mac.programmer
Subject: Need MacApp Help ...
Message-ID: <1963@gould.doc.ic.ac.uk>
Date: 6 Jun 90 17:57:56 GMT
Sender: news@doc.ic.ac.uk
Organization: DoC., Imperial College, London, England
Lines: 35


I'm creating a TPalette class in MacApp to implement the kind of tool
palettes you see in MacDraw windows. It contains subviews of type
TPaletteIcon which represent the individual tools.

I've made TPalette a sub-class of TControl and TPaletteIcon a subclass
of TIcon. My intention was to have a field called fCurrTool in
TPalette which will be a reference to the current tool (i.e. a
TPaletteIcon object), and have this field initialised in the IRES
method of TPalette to the default tool.

However, it seems that the fSubViews field of a view is not set up at
the time its IRES method is called. Does anyone know of a workaround ?

I've thought of just making fCurrTool an integer which corresponds to
the position of the tool within the palette, but this will mean more
work when it comes to hiliting/unhiliting the tools, since there
doesn't seem to be a direct way of retrieving the n-th element of a
list. My current 'fix' is to make fCurrTool record the fIdentifier of
the current tool, and call FindSubView to retrieve it when necessary.

Perhaps the question I should really ask is : does what I'm doing
above look sensible ? I'm new to OOP and MacApp and working without
the 'MacApp Cookbook' and 'Intro to MacApp ...' manuals doesn't make
life any easier. (I'm waiting to hear from ADG, the U.K. equivalent of
APDA).    Oh, I'm using MacApp 2.0b9 with Think Pascal 3.0.

---------------------

Keng Ng
Dept of Computing
Imperial College
180 Queen's Gate
London SW7 2BZ
Tel: +44 71 589 5111 ext 5091