TkEntry - how do I read/capture what was typed?

Ruby
1

I would like a working example please

2

I know how to create an TKentry field but I cannot figure out how to
capture what was typed…anybody have worked out examples?

3

You must associate a Tk variable object to your Entry field :

@myVar = TkVariable.new
@myEntryField.textvariable(@myVar)
…
@myEntry = @myVar.value

Examples of tk programming here :
http://www.ugcs.caltech.edu/~rise/tk-demos/

Hope this help.

4

below is the relevant section of my code
entry1 = TkEntry.new(root) {
}
entry2 = TkEntry.new(root) do
show ‘*’
end

variable1 = TkVariable.new
variable2 = TkVariable.new

entry1.textvariable = variable1
entry2.textvariable = variable2

variable1.value = “”
variable2.value = “Enter any confidential value”

@myVar = TkVariable.new
@entry1.textvariable(@myVar) #<=givbes undefined method
@myEntry = @myVar.value

entry1.place(‘height’ => 25,
‘width’ => 150,
‘x’ => 10,
‘y’ => 10)

entry2.place(‘height’ => 25,
‘width’ => 150,
‘x’ => 10,
‘y’ => 40)
Tk.mainloop

5

entry1.textvariable = variable1
entry1.place(‘height’ => 25,
‘width’ => 150,
‘x’ => 10,
‘y’ => 10)

entry2.place(‘height’ => 25,
‘width’ => 150,
‘x’ => 10,
‘y’ => 40)
Tk.mainloop

@entry1 specifies an instance variable in a class and is not defined in
your code. Has probably the nil value.

I believe that it’s not a good design to process the value of an entry
field when it has just been typed (if possible with tk ?). Usually, you
grab the value when an OK button has been clicked.

6

Thanks Michel

can TKEntry invoke a defined procedure to grab that input when the user
is done typing?

Also, I tried this:
@myVar = TkVariable.new
@entry1.textvariable(@myVar)
@myEntry = @myVar.value

and it gave an undefined method error on entry1.textvariable(@myVar)

any ideas?

Joe

7

Hi,

From: Joe C. [email protected]
Subject: Re: TkEntry - how do I read/capture what was typed?
Date: Tue, 6 Sep 2011 21:38:21 +0900
Message-ID: [email protected]

can TKEntry invoke a defined procedure to grab that input when the user
is done typing?

How about this?

require ‘tk’

class PasswdEntry < TkFrame
def initialize(*args)
super(*args)
@frame = self

width = 15

# create widgets
@label1 = TkLabel.new(@frame, :text=>'Password ')
@var1   = TkVariable.new
@entry1 = TkEntry.new(@frame, :textvariable=>@var1,
                      :width=>width, :show=>'*',
:foreground=>'red')
@passwd_ok = false

@label2 = TkLabel.new(@frame, :text=>'Re-Type ')
@var2   = TkVariable.new
@entry2 = TkEntry.new(@frame, :textvariable=>@var2,
                      :width=>width, :show=>'*',
:foreground=>'red')
@retype_ok = false

# grid widgets
TkGrid.column(@frame, 0, :weight=>0)
TkGrid.column(@frame, 1, :weight=>1)

@label1.grid(:row=>0, :column=>0, :sticky=>'w')
@entry1.grid(:row=>0, :column=>1, :sticky=>'news')

@label2.grid(:row=>1, :column=>0, :sticky=>'w')
@entry2.grid(:row=>1, :column=>1, :sticky=>'news')

# trace variables
@var1.trace(:write){|var, idx, op| check_passwd(var.value)}
@var2.trace(:write){|var, idx, op| check_retype(var.value)}

# define bindings
@entry1.bind('Return'){@entry2.focus if @passwd_ok}
@entry2.bind('Return'){
  if @cmd && @passwd_ok && @retype_ok
    @cmd.call(@var1.value)
    @entry1.focus
  end
}

end

def callback(&block)
@cmd = block
end

def focus
@entry1.focus
end

def get_passwd
if @passwd_ok && @retype_ok
@var1.value
else
false
end
end

######################
private
######################
def check_passwd(str)
# check pattern of password string
#if str.length >= 6 && str =~ /\d/ && str =~ /[A-Z]/ && str =~
/[a-z]/
if str.length >= 6
@entry1.foreground ‘black’
@passwd_ok = true
else
@entry1.foreground ‘red’
@passwd_ok = false
end
end

def check_retype(str)
if @passwd_ok && str == @var1.value
@entry2.foreground ‘black’
@retype_ok = true
else
@entry2.foreground ‘red’
@retype_ok = false
end
end
end

passwd = PasswdEntry.new.pack

btn = TkButton.new(:text=>‘print passwd’,
:command=>proc{p passwd.get_passwd}).pack

passwd.callback{|str| btn.invoke}
passwd.focus

Tk.mainloop