First of all, keep in mind that I'm rather new at Palm
programming. :)
When modifying a field's text, the book I use for
reference (the great book by O'reilly) states that
"you must use a handle instead of a pointer. The
ability to resize the text requires the use of a
handle." It then shows an example, which I used in my
code:
static FieldPtr SetFieldTextFromHandle(Word fieldID,
Handle txtH)
{
Handle oldTxtH;
FormPtr frm = FrmGetActiveForm();
FieldPtr fldP;
//Get the field's current text handle
fldP =
FrmGetObjectPtr(frm,FrmGetObjectIndex(frm,fieldID));
oldTxtH = FldGetTextHandle(fldP);
// set the field's text to the new text
FldSetTextHandle(fldP,txtH);
FldDrawField(fldP);
//free the handle AFTER we call FldSetTextHandle().
if (oldTxtH)
MemHandleFree(oldTxtH);
return fldP;
}
This, as well as several wrapper functions for it
(most provided by the O'reilly book as well), allows
me to pretty much do whatever I need to do with a
field's text.
I hope this helps (and that I'm not stupidly stating
the obvious!)
Alias,
Fletch
--- Mike Davis <[EMAIL PROTECTED]> wrote:
> > Are you willing to give a snippet of code, showing
> the
> > offending line, as well as a few lines above and
> > below?
>
> I can give you all the lines of code for problem 2.
> I still have
> not figured out exactly where the error is on
> problem 1. I see one
> on power up and after many operaionts.
>
> But problem 2 is easy to show: Basically I have a
> form with a field
> where a number is displayed in the field. When the
> number of digits
> goes from 1 to 2 or 2 to 1 there is an "invalid
> field length" error.
> If I go from 2 to 2 or 1 to 1, there is no error.
>
> The field is non editable and initial size set to
> 10. All I do is
> determine the number and convert it to a string. I
> then call
> a function and pass the pointer to the string. The
> string is a
> global array, so it has global life.
>
> The function that does the conversion:
>
> StrIToA(curBtnStr, fmod(btn,12) + 1);
> SetFieldText(fldBtn, curBtnStr);
>
> Here is the function call that I use to set the
> field text:
>
> void SetFieldText(Word id, char *s) {
> FormPtr frmp;
> FieldPtr fldp;
> FieldAttrType fa;
>
> frmp=FrmGetActiveForm();
> fldp=FrmGetObjectPtr(frmp,
> FrmGetObjectIndex(frmp, id));
> FldGetAttributes(fldp, &fa);
>
> if (fa.editable == TRUE){
> FldDelete(fldp, 0, FldGetTextLength(fldp));
> FldInsert(fldp, s, StrLen(s));
> }
> else{
> FldSetSelection(fldp, 0,0); // clear
> selections
> FldSetTextPtr(fldp, s);
> }
> FldDrawField(fldp);
> }
>
> That is the entire code. If I comment out the
> SetFieldText(), there
> is no error (obviously). But I don't see any
> problem with this
> method of writing text to a field. I do this many
> other places
> without problems.
>
> Any clues?
>
>
>
> > Fletch
> >
> > --- Mike Davis <[EMAIL PROTECTED]> wrote:
> > > I have tested my app as a PalmIIIx using Bebug
> Rom
> > > 3.0. Every
> > > thing tests ok.
> > >
> > > Then I switched to using 3.3 Debug ROM and get
> two
> > > errors
> > > immediately. I'm sure there will be others. I
> need
> > > to fix this
> > > quickly as possible as the app is already
> released.
> > > Fortunately, it
> > > recommends OS 3.0 but I would like it compatible
> > > with all versions of
> > > the OS.
> > >
> > > The two errors:
> > > 1) Field.c, Line: 123, Invalid insertion point
> > > position.
> > >
> > > 2) Field.c, Line: 136, Invalid Field Length.
> This
> > > one appears to
> > > happen when the output to the field changes
> size.
> > > My output is either
> > > one digit or two digits. If I change from one
> value
> > > to another and
> > > both are single digit, no problem. If I change
> from
> > > one value to
> > > another and both are 2 digits, no problem. The
> > > problem occurs when
> > > going from 2 to 1 or 1 to 2 only. The field
> width
> > > attribute is
> > > set to 10.
> > >
> > > I would like to understand these two errors.
> > >
> > > First, would either of these two cause a Fatal
> Error
> > > on a palm using
> > > OS 3.3, or is just something that POSE catches
> that
> > > should be fixed.
> > >
> > > Second, why is this an error in 3.3 but not in
> 3.0?
> > > Cause?
> > > --
> > >
> >
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