In article <65518@palm-dev-forum>,
Joe Programmer <[EMAIL PROTECTED]> wrote:
> I am using the code below to show or hide the bitmap
> and the button. On OS versions < 3.2 (I tested on
> 2.0, 3.0, 3.1 , 3.3, 3.5, and 4.0), the button gets
> corrupted (a sloppy rectangle is displayed at the
> wrong location and it doesn't respond to taps). On OS
> versions >= 3.3 it works as expected.
>
> Does anyone have any suggestions?
The documentation for FrmHideObject states explicitly that prior to 3.2,
the usable bit wasn't cleared, and that you should explicitly clear it
yourself. This unfortunately means directly touching system structures,
which is now a no-no, but I don't think there's any way around it, yet.
So if you're running in the emuolator, you need to turn off the
UIDataMagr Access checkbox in the Debugging panel (or put up with the
alerts it generates). Here's a routine that I use that might help:
void FrmReallyHideObject(FormPtr frmP, UInt16 objIndex)
{
FormObjectKind objKind;
void* objP;
UInt32 osVersion;
FtrGet( sysFtrCreator, sysFtrNumROMVersion, &osVersion );
// Prior to OS 3.2, FrmHideObject doesn't actually set the usable bit.
// As recommended, we set it manually here (a pain, since the location
// of the bit is type-dependent!).
FrmHideObject(frmP, objIndex);
objKind = FrmGetObjectType(frmP, objIndex);
objP = FrmGetObjectPtr(frmP, objIndex);
// !!! Note: this is not a complete list of types. We're only doing
// the ones we know we need right now
if (osVersion < sysMakeROMVersion(3,2,0,sysROMStageRelease,0))
{
switch( objKind )
{
case frmControlObj:
((ControlType*)(objP))->attr.usable = 0;
break;
case frmBitmapObj:
((FormBitmapType*)(objP))->attr.usable = 0;
break;
case frmGadgetObj:
((FormGadgetType*)(objP))->attr.usable = 0;
break;
case frmLabelObj:
((FormLabelType*)(objP))->attr.usable = 0;
break;
case frmScrollBarObj:
((ScrollBarType*)(objP))->attr.usable = 0;
break;
default:
break;
}
}
}
Hope that helps,
Dave Johnson
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