Key press event

Desktop wxRuby
1

Hello all
I am new to fxruby and coming from php-gtk and rubygnome

I can not seem to capture key press events with this code
the code was modified from an online example

ruby 1.8.7, ubuntu 9.04, wxruby2.0.0

nothing is echoed to the command line
i also tried exit in the block and nothing

thanks in advance

include Wx
class MyFrame < Frame
def initialize
super(nil, -1, “Test Key Press Event”)
evt_key_down { |ev| puts ‘a key was pressed’ }
end

end

class MinimalApp < App
def on_init
MyFrame.new.show
end
end
MinimalApp.new.main_loop

happy coding
brad

2

Brad, your code worked fine for me.

Just added:
require ‘rubygems’
require ‘wx’
before include Wx

and changed { |ev| puts ‘a key was pressed’ }
to { |ev| message_box(‘a key was pressed’) }
just to make it easier to see the results

3

Dimas C. wrote:

Brad, your code worked fine for me.

Just added:
require ‘rubygems’
require ‘wx’
before include Wx

and changed { |ev| puts ‘a key was pressed’ }
to { |ev| message_box(‘a key was pressed’) }
just to make it easier to see the results

Dimas thanks for the reply

I neglected to put those lines in my post but they are in the code

what OS are you using, ruby version, & wxruby version ?

I got the code to work if I connected the event handler to a Wx::Panel,
but that will not solve the problem.
When the event handler is connected to the panel and the user touches
another
widget on the screen that widget will now have focus and the panel will
no
longer receive the key press events.

I need the event handler connected to the Frame/Window and listen for
event
even if it does not have focus.
I am reading from a bar code scanner that sends the data as keyboard
input.

thanks & happy coding
brad

4

Hi Brad

Brad Montgomery wrote:

I got the code to work if I connected the event handler to a Wx::Panel,
but that will not solve the problem.
When the event handler is connected to the panel and the user touches
another
widget on the screen that widget will now have focus and the panel will
no
longer receive the key press events.

By default, only events that are CommandEvents (those associated with
defined actions on controls, like clicking a button, typing text in a
TextCtrl) propagate up the window hierarchy to the parent. Other types
of events, such as MouseEvents and KeyEvents are only received by the
window/widget that currently has focus. So if you have a Panel on top of
a Frame, once the Panel child has had the event, it won’t propagate
further.

http://wxruby.rubyforge.org/doc/eventhandlingoverview.html

I need the event handler connected to the Frame/Window and listen for
event
even if it does not have focus.
I am reading from a bar code scanner that sends the data as keyboard
input.

The above normally makes sense for interaction, but I can see it’s a bit
inconvenient for this less usual situation. There are various ways you
could work round this. If you have only a single frame receiving data,
and a small number of windows within it, you could capture the key press
event on all of them, and then manipulate the received event’s
propagation level with methods like resume_propagation. See this python
example:

http://wiki.wxpython.org/index.cgi/EventPropagation

If the bar code data is such that it is represented by only a small
number of different possible keys you could try using an
acceleratortable, which directs all key presses within a frame to menu
items

http://wxruby.rubyforge.org/doc/acceleratortable.html

hth
alex