wxruby users - Mar 2007 - object-oriented GUI design and event handling

I''m trying to setup a fairly simple GUI with Ruby to perform some SQL 
queries. There are a few drop-down boxes where users can select 
different options and then one button that when clicked should get the 
text from each drop-down in order to perform the query. Once it gets the 
result it should display it to a text control. The problem is I am not 
sure how to actually reference each drop-down box in the frame or the 
text control. If I add the control directly to the frame there is no 
reference or name for that control that my button can later use. I have 
tried looking through sample code but most of the samples I found were 
for larger programs with many features and I couldn''t really find the 
answer I was looking for. Could someone give me an idea of how to 
accomplish this or maybe a link to some reference that may help? It 
doesn''t seem like it would be that difficult but I''m just not
sure how
to get started.

Thanks,
Alex Ciarlillo

Hi Alex,

Are you doing this with WxSugar or solely with WxRuby2?  If you''re
using WxSugar you could do something like the following:

# Begin Code
require ''wx''
require ''wx_sugar''

class MainFrame < Wx::Frame
  def initialize(*args)
    super
    @buttons = []
    @buttons << add( Wx::Choice[ :choices =>
("1".."5").to_a ] )
    @buttons << add( Wx::Choice[ :choices =>
("a".."e").to_a ] )
    @buttons << add( Wx::Choice[ :choices =>
("F".."J").to_a ] )
    add( Wx::Button[ :label => ''Do Something''] ) do
|button|
      listen(:button,button) do |event|
        @textctrl.value =
@buttons.map{|but|but.string_selection}.join('','')
      end
    end
    @textctrl = add( Wx::TextCtrl[] )
  end
end

class MyApp < Wx::App
  def on_init
    MainFrame.new( nil, :title => "SQL Application" ).show
  end
end

MyApp.new.main_loop
# End Code

As for plain WxRuby, it''s a little more involved but will follow
basically the same principles (I''d recommend WxSugar - it makes things
much more rubyish)

Cheers

On 3/29/07, Alex Ciarlillo <ac251404 at ohio.edu>
wrote:
> I''m trying to setup a fairly simple GUI with Ruby to perform some
SQL
> ...
> to get started.
>
> Thanks,
> Alex Ciarlillo
> _______________________________________________
> wxruby-users mailing list
> wxruby-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/wxruby-users
>

-- 
-Phil <><

Hi Alex

Alex Ciarlillo wrote:
> I''m trying to setup a fairly simple GUI with Ruby to perform some
SQL
> queries. There are a few drop-down boxes where users can select 
> different options and then one button that when clicked should get the 
> text from each drop-down in order to perform the query. Once it gets the 
> result it should display it to a text control. The problem is I am not 
> sure how to actually reference each drop-down box in the frame or the 
> text control. 
For most simpler apps, the easiest way to reference widgets (e.g. a 
drop-down box) is to store it as a ruby instance variable of the 
containing frame when you create it.

Then you can refer to them later in your event handler, either directly 
through an instance variable, or by ordinary ruby accessor methods. The 
latter is slightly more work, but as generally in ruby helps avoid typo 
errors and documents your frame class.

A simple example using wxSugar might look something like:

class SimpleFrame < Wx::Frame
  attr_reader :colour_ch, :size_ch, :results
  def initialize(parent)
    super(parent, :title => ''Database App'')
    # set up some drop downs, an action button and a results display
    panel = add(Wx::Panel, :proportion => 1)
    panel.arrange_vertically(:padding => 8) do
      colours = %w[red blue green orange black]
      @colour_ch = panel.add( Wx::Choice[:choices => colours])
     
      sizes = %w[small medium large]
      @size_ch = panel.add( Wx::Choice[:choices => sizes])

      panel.add( Wx::Button[:label => ''Find'' ] ) do |
@button |
        listen(:button, @button, :on_find)
      end
     
      @results = panel.add( Wx::TextCtrl[:style => Wx::TE_MULTILINE],
                            :proportion => 1)
    end
  end

  def on_find
    what_colour = colour_ch.string( colour_ch.selection )
    what_size   = size_ch.string( size_ch.selection )
    # Do retrieval from the database here ...
    results.value = "Results for ''#{what_colour},
#{what_size}'' ..."
  end
end


hth
alex

Thanks to both of you for getting me on the right track with this. 
Everything is coming together fine now except a problem I am having with 
CheckListBox. I would like the user to be able to select multiple items 
from certain lists so I thought this control would work, but now I
can''t
figure out how to get at the selections. I changed colour_ch in Alex''s 
example to a checklistbox but doing colour_ch.selections returns 
nothing. I read in the wxRuby docs that you are supposed to pass an 
array to be filled when using ListBox.get_selections but when I try that 
it gives me an error that I passed 1 argument where 0 is expected. I 
thought I would be able to do something like the following:

what_colour = colour_ch.selections.map{|s|
colour_ch.string(s)}.join('','')

So that''s my guess and even though its wrong I believe its clear that 
I''m just trying to get a comma seperated string of all the items 
selected in that control. How should I be attempting this?

Thanks,
-alex c.

Hi Alex C,

Wx::ChecklistBox#selections() won''t return the checked items - it will
return the items that are selected (if you''re on Windows, the ones
that are highlighted blue in the control).  To get a list of the
checked items, do something like the following:

what_colour = (0..(colour_ch.number)).to_a.map{ |n|
colour_ch.string(n) }.join('','')

(not sure if that''s the exact syntax, but it should be close).
As well, I''m not sure, but WxSugar might let you do something like the
following:

what_colour = colour_ch.each { |index| colour_ch.string(index)
}.join('','')

And, if that doesn''t work right now, would that be something useful to
add to WxSugar, Alex F?

On 3/30/07, Alex Ciarlillo <ac251404 at ohio.edu>
wrote:
> Thanks to both of you for getting me on the right track with this.
> Everything is coming together fine now except a problem I am having with
> CheckListBox. I would like the user to be able to select multiple items
> from certain lists so I thought this control would work, but now I
can''t
> figure out how to get at the selections. I changed colour_ch in
Alex''s
> example to a checklistbox but doing colour_ch.selections returns
> nothing. I read in the wxRuby docs that you are supposed to pass an
> array to be filled when using ListBox.get_selections but when I try that
> it gives me an error that I passed 1 argument where 0 is expected. I
> thought I would be able to do something like the following:
>
> what_colour = colour_ch.selections.map{|s|
colour_ch.string(s)}.join('','')
>
> So that''s my guess and even though its wrong I believe its clear
that
> I''m just trying to get a comma seperated string of all the items
> selected in that control. How should I be attempting this?
>
> Thanks,
> -alex c.
> _______________________________________________
> wxruby-users mailing list
> wxruby-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/wxruby-users
>

-- 
-Phil <><

I made an oopsie (that''s in the documentation) ...
Wx::ControlWithItems#number is not defined, you need to use
Wx::ControlWithItems#count instead, so the first example should be:

what_colour = (0..(colour_ch.count)).to_a.map{ |n|
colour_ch.string(n) }.join('','')


On 3/30/07, Philip Schalm <pnomolos at gmail.com>
wrote:
> Hi Alex C,
>
> Wx::ChecklistBox#selections() won''t return the checked items - it
will
> return the items that are selected (if you''re on Windows, the ones
> that are highlighted blue in the control).  To get a list of the
> checked items, do something like the following:
>
> what_colour = (0..(colour_ch.number)).to_a.map{ |n|
> colour_ch.string(n) }.join('','')
>
> (not sure if that''s the exact syntax, but it should be close).
> As well, I''m not sure, but WxSugar might let you do something like
the
> following:
>
> what_colour = colour_ch.each { |index| colour_ch.string(index)
}.join('','')
>
> And, if that doesn''t work right now, would that be something
useful to
> add to WxSugar, Alex F?
>
> On 3/30/07, Alex Ciarlillo <ac251404 at ohio.edu> wrote:
> > Thanks to both of you for getting me on the right track with this.
> > Everything is coming together fine now except a problem I am having
with
> > CheckListBox. I would like the user to be able to select multiple
items
> > from certain lists so I thought this control would work, but now I
can''t
> > figure out how to get at the selections. I changed colour_ch in
Alex''s
> > example to a checklistbox but doing colour_ch.selections returns
> > nothing. I read in the wxRuby docs that you are supposed to pass an
> > array to be filled when using ListBox.get_selections but when I try
that
> > it gives me an error that I passed 1 argument where 0 is expected. I
> > thought I would be able to do something like the following:
> >
> > what_colour = colour_ch.selections.map{|s|
colour_ch.string(s)}.join('','')
> >
> > So that''s my guess and even though its wrong I believe its
clear that
> > I''m just trying to get a comma seperated string of all the
items
> > selected in that control. How should I be attempting this?
> >
> > Thanks,
> > -alex c.
> > _______________________________________________
> > wxruby-users mailing list
> > wxruby-users at rubyforge.org
> > http://rubyforge.org/mailman/listinfo/wxruby-users
> >
>
>
> --
> -Phil <><
>

-- 
-Phil <><

Alex Ciarlillo wrote:
> Everything is coming together fine now except a problem I am having with 
> CheckListBox. I would like the user to be able to select multiple items 
> from certain lists so I thought this control would work, but now I
can''t
> figure out how to get at the selections. 
....
> what_colour = colour_ch.selections.map{|s|
colour_ch.string(s)}.join('','')
>   
This is right. I''ve tried it out myself and I think there''s a
bug in
CheckListBox - the method always seems to return [0]. This is a bit 
strange because the same method works fine in ListBox where the method 
is inherited from.

Anyway I will look into it, hopefully can fix it pretty easily for the 
next release. I guess you could use ListBox in the interim - 
samples/bigdemo/wxListBox in the main wxruby2 dist illustrates how to 
use get_selections.

Thanks for the report.

alex

Philip Schalm wrote:
> Wx::ChecklistBox#selections() won''t return the checked items - it
will
> return the items that are selected (if you''re on Windows, the ones
> that are highlighted blue in the control).  To get a list of the
> checked items, do something like the following:
>   
> what_colour = (0..(colour_ch.number)).to_a.map{ |n|
> colour_ch.string(n) }.join('','')
>   
Oops, I should have read this email first. Alex - ignore my previous 
email, Philip''s quite right that get_selections doesn''t return
the
checked items.

The sort of thing you want is

* items = (0 .. count).to_a
 checked = items.select { | i | checked?(i) }.map { | i | string(i)

This works fine for me. *No bug ... I must be paranoid.
> As well, I''m not sure, but WxSugar might let you do something like
the
> following:
>
> what_colour = colour_ch.each { |index| colour_ch.string(index)
}.join('','')
>
> And, if that doesn''t work right now, would that be something
useful to
> add to WxSugar, Alex F?
>   
yes -  I''ve been experimenting with some methods to improve working
with
ControlWithItems classes, but they didn''t make it in the last release. 
We''ll look to put it in the next one.

thanks
a