Re: GtkEntry and numeric floating point input

[Neil Zanella <nzanella gmail com>]

Hello... thank you for your reply.

But let me add to my question, what is the most appropriate way to
provide a widget
that supports monetary values? Given that the valid monetary values to
be supported
are going to be locale specific how can this be done in a portable way?

Thanks,

Neil

On Mon, 29 Nov 2004 07:29:03 -0800, Vlietstra, Joe (NSSD)
<joe vlietstra ngc com> wrote:
> Neil Zanella <nzanella gmail com> wrote:
> 
> 
> > I've got a GtkEntry and I need to confine user input into this widget
> > to numeric values which will fit into the underlying C data types.
> > What is the best way to do this? If the values were only allowed to
> > be integers I'd use a GtkSpinBox (I think that's what it's > called),
> > but since they are now allowed to have decimal points etc...
> > what should I do to be sure the user doesn't enter invalid data.
> > What's the best way?
> 
> GtkSpinButton will work for both integer and floating-point numbers.
> See "Example 2" in the API documentation at:
>    http://developer.gnome.org/doc/API/2.0/gtk/GtkSpinButton.html
> 
> We use spin buttons in instrumentation control (power supplies,
> RF sources, etc.).  Spin button range checking works well and our
> operators like the up/down arrows.
> 
> There are three properties of spin buttons that you may need to think
> about:
> -- Non-numeric characters
>    Default spin button behavior reacts to non-numeric keys.
>    We've never found a use/benefit for this behavior (hex entry?).
>    Use gtk_spin_button_set_numeric to ignore non-numeric characters.
>    API documentation is contradictory (description of "numeric"
>    parameter is opposite of function summary).  Set the "numeric"
>    parameter to TRUE to ignore non-numeric characters.
> -- Snap to tick
>    Default spin button behavior allows operator to enter a value
>    that is not on a "tick" (up/down arrow) boundary.  This is
>    desirable most of the time but you may need to call
>    gtk_spin_button_set_snap_to_ticks to change this behavior.
>    Example: Resolution of RF synthesizer hardware is 0.02 dB.
>    Synthesizer will accept commands at finer resolution and
>    quietly change the RF output to the nearest 0.02 dB tick.
>    Better to have the application snap to tick than the hardware.
> -- Update policy
>    99% of the time the default policy (GTK_UPDATE_ALWAYS) is what
>    you want.  The spin button will be able to display a value that
>    isn't in the range of the adjustment.  This can be handy.
>    Example:  Application will query the voltage level from a DC
>    power supply during initialization and display it in the spin
>    button; this voltage level may be out of range but you need to
>    inform the operator of the actual level.
> 
> Joe Vlietstra
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