at_tab - changes widget focus

SYNOPSIS

at_tab entrylist

ARGUMENTS

entrylist

A list of text entry widgets that the focus will move about. The list should be in the order of progression.

DESCRIPTION

This procedure is part of the standard AT_DEFS. It allows the programmer to cuase the focus of text widgets to be moved to the next logical text widget. This could be implemented as the command associated with a binding when defining a text widget. For reasons of style, we recommend using the key to do this, but it may be conceivable to bind other keys (e.g. in a "form" situation).

Example

Here is some example code that can be used to create a text widget, add a binding to the key which calls the at_tab command. At the risk of making the example slightly complicated, I've ensured that the code here is complete in its own right.

#+
# Title       Demo
#
# Function    Demonstrates the "at_tab" procedure.
#
# Author      Derek McKay
# Date        1-Dec-1994
#-
source at\$tk_include:at_defs.atk

#+
# Routine     make_entry
# Function    This procedure makes a text entry widget given a widget
#             name and a label as arguments. It binds  and .
#
# Author      Derek McKay
# Date        1-Dec-1994
#
# Call
proc make_entry {widget label} {
  global entrylist
#-
  frame .$widget
  pack .$widget -side top
  entry .$widget.entry -width 12 -relief sunken -width 16
  label  .$widget.label -text "$label:" -width 16
  pack .$widget.entry -side right -in .$widget\
    -anchor e
  pack .$widget.label -side left -in .$widget\
    -anchor w
  bind .$widget.entry  \
    "puts stdout \"Widget($widget) returned \[.$widget.entry get\]\""
  bind .$widget.entry  "at_tab \$entrylist"
  lappend entrylist ".$widget.entry"
}  

make_entry ra "Right Ascension"
make_entry dec Declination
make_entry az Azimuth
make_entry el Elevation

button .quit -text Quit -command exit -fg red
pack .quit -side bottom -expand yes -fill x

#EOF

When you run the script, try typing text, numbers <Tab>s and <Returns>s in the various text boxes.

KEYWORDS