Yes, I have the same problems too, also even I have set the gadgethandler
for the extended gadget, I still cannot see the gadget display on the form.
Also, it seems cannot capture the ctlSelectEvent when I try to tap on the
postion the gadget suppose to be. moreover, how can I draw something in the
gadget? Just draw another bitmap at the same position as the gadget and
overlap it? So, can anyone give us detail help on those gadget problems? I
have already try lots of ways to solve it for a week, but still nothing go
smoothly...........Please help!
Oscar
----- Original Message -----
From: "Gerald Stap" <[EMAIL PROTECTED]>
To: "Palm Developer Forum" <[EMAIL PROTECTED]>
Sent: Thursday, February 15, 2001 12:52 PM
Subject: Problem creating extended gadgets
> What is a clean and correct way of creating extended gadgets?
>
> I'm a newbie and I have been at this for some days now so if anybody
> could clear this mystery up I would be obliged.
>
> Setup:
> The app I'm writing is for color enabled Palm devices only and for
> PalmOS 3.5 and up. Devtools are cygwin/gcc, pilrc, prc-tools, PalmOS 3.5
> SDK and Pose3.0a8.
>
> Problem:
> I've got a form with 64 gadgets on it and all have to be extended
> gadgets. That is, they need to have a gadgethandler.
> If I understand correctly, the difference between a normal gadget an an
> extended gadget is the extended bit defined in the FormGadgetAttrType
> structure. If this bit is set the FormGadgetType structure has also got
> a 'handler' field which is a pointer of type FormGadgetHandlerType.
> The question is; who or what sets this bit and when?
>
> I've searched extensively (and maybe I've missed something) but the
> PalmOS reference.pdf says nothing about a function to manipulate this
> bit (it says your code should treat the FormGadgetType structure as
> opaque) and so I thought that using FrmSetGadgetHandler would take care
> of the setting of this bit. It didn't because my gadgethandler wasn't
> called.
>
> When I do not treat the structure as opaque and set the bit myself, my
> handler is called after registerring it with FrmSetGadgetHandler and
> everything seems to work fine for all gadgets with even objectID.
> However, the gadgets with odd objectID do not get their handle set
> because FrmGetObjectIndex fails.
>
> I suspect this is a side effect of setting the gadget handlers for the
> gadgets with even objectID's. Apparently, setting the bit is not enough
> to create an extended gadget because additional space has to be
> allocated for the gadethandler pointer field in the FormGadgetType
> structure. So when you just set the extended bit and call
> FrmSetGadgetHandler you write outside the bounds of the structure thus
> corrupting the next resource structure or some other data. That's why my
> gadgets with the odd objectID's fail when calling FrmGetObjectIndex.
>
> So how do I create a legal extendend gadget? Would it be possible to
> create an extended gadget with FrmNewGadget()? Or should it be done at
> resource-editor level? (The only bit I can alter through pilrc is the
> 'usable' bit). Can extended gadget resources be created with Constructor
> for CW? Are assumptions made above correct?
>
> Thanx,
>
> Gerald
>
> PS. There are some major bugs in Listing 3.5 (palmos 3.5 gadget example)
> of the PalmOS companion pdf. Copy paste won't work, B warned!
>
>
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