NAME¶
Tk::Entry - Create and manipulate Entry widgets
SYNOPSIS¶
$entry =
$parent->
Entry(?
options?);
STANDARD OPTIONS¶
-background -highlightbackground -insertontime -selectforeground
-borderwidth -highlightcolor -insertwidth -takefocus
-cursor -highlightthickness -justify -textvariable
-exportselection -insertbackground -relief -xscrollcommand
-font -insertborderwidth -selectbackground
-foreground -insertofftime -selectborderwidth
- Command-Line Name: -disabledbackground
- Database Name: disabledBackground
- Database Class: DisabledBackground
- Specifies the background color to use when the entry is
disabled. If this option is the empty string, the normal background color
is used.
- Command-Line Name: -disabledforeground
- Database Name: disabledForeground
- Database Class: DisabledForeground
- Specifies the foreground color to use when the entry is
disabled. If this option is the empty string, the normal foreground color
is used.
- Name: invalidCommand
- Class: InvalidCommand
- Switch: -invalidcommand
- Alias: -invcmd
- Specifies a script to eval when validateCommand
returns 0. Setting it to <undef> disables this feature (the
default). The best use of this option is to set it to bell. See
Validation below for more information.
- Command-Line Name: -readonlybackground
- Database Name: readonlyBackground
- Database Class: ReadonlyBackground
- Specifies the background color to use when the entry is
read-only. If this option is the empty string, the normal background color
is used.
- Name: show
- Class: Show
- Switch: -show
- If this option is specified, then the true contents of the
entry are not displayed in the window. Instead, each character in the
entry's value will be displayed as the first character in the value of
this option, such as ``*''. This is useful, for example, if the entry is
to be used to enter a password. If characters in the entry are selected
and copied elsewhere, the information copied will be what is displayed,
not the true contents of the entry.
- Name: state
- Class: State
- Switch: -state
- Specifies one of three states for the entry: normal,
disabled, or readonly. If the entry is readonly, then
the value may not be changed using widget commands and no insertion cursor
will be displayed, even if the input focus is in the widget; the contents
of the widget may still be selected. If the entry is disabled, the
value may not be changed, no insertion cursor will be displayed, the
contents will not be selectable, and the entry may be displayed in a
different color, depending on the values of the -disabledforeground
and -disabledbackground options.
- Name: validate
- Class: Validate
- Switch: -validate
- Specifies the mode in which validation should operate:
none, focus, focusin, focusout, key, or
all. It defaults to none. When you want validation, you must
explicitly state which mode you wish to use. See Validation below
for more.
- Name: validateCommand
- Class: ValidateCommand
- Switch: -validatecommand
- Alias: -vcmd
- Specifies a script to eval when you want to validate the
input into the entry widget. Setting it to "undef" disables this
feature (the default). This command must return a valid boolean value. If
it returns 0 (or the valid boolean equivalent) then it means you reject
the new edition and it will not occur and the invalidCommand will
be evaluated if it is set. If it returns 1, then the new edition occurs.
See Validation below for more information.
- Name: width
- Class: Width
- Switch: -width
- Specifies an integer value indicating the desired width of
the entry window, in average-size characters of the widget's font. If the
value is less than or equal to zero, the widget picks a size just large
enough to hold its current text.
DESCRIPTION¶
The
Entry method creates a new window (given by the $entry argument) and
makes it into an entry widget. Additional options, described above, may be
specified on the command line or in the option database to configure aspects
of the entry such as its colors, font, and relief. The
entry command
returns its $entry argument. At the time this command is invoked, there must
not exist a window named $entry, but $entry's parent must exist.
An entry is a widget that displays a one-line text string and allows that string
to be edited using methods described below, which are typically bound to
keystrokes and mouse actions. When first created, an entry's string is empty.
A portion of the entry may be selected as described below. If an entry is
exporting its selection (see the
exportSelection option), then it will
observe the standard X11 protocols for handling the selection; entry
selections are available as type
STRING. Entries also observe the
standard Tk rules for dealing with the input focus. When an entry has the
input focus it displays an
insertion cursor to indicate where new
characters will be inserted.
Entries are capable of displaying strings that are too long to fit entirely
within the widget's window. In this case, only a portion of the string will be
displayed; methods described below may be used to change the view in the
window. Entries use the standard
xScrollCommand mechanism for
interacting with scrollbars (see the description of the
-xscrollcommand
option for details). They also support scanning, as described below.
VALIDATION¶
Validation of entry widgets is derived from part of the patch written by
jhobbs@cs.uoregon.edu. This works by setting the
validateCommand option
to a callback which will be evaluated according to the
validate option
as follows:
- none
- Default. This means no validation will occur.
- focus
- validateCommand will be called when the entry
receives or loses focus.
- focusin
- validateCommand will be called when the entry
receives focus.
- focusout
- validateCommand will be called when the entry loses
focus.
- key
- validateCommand will be called when the entry is
edited.
- all
- validateCommand will be called for all above
conditions.
The
validateCommand and
invalidCommand are called with the
following arguments:
- •
- The proposed value of the entry. If you are configuring the
entry widget to have a new textvariable, this will be the value of that
textvariable.
- •
- The characters to be added (or deleted). This will be
"undef" if validation is due to focus, explcit call to validate
or if change is due to "-textvariable" changing.
- •
- The current value of entry i.e. before the proposed
change.
- •
- index of char string to be added/deleted, if any. -1
otherwise
- •
- type of action. 1 == INSERT, 0 == DELETE, -1 if it's a
forced validation or textvariable validation
In general, the
textVariable and
validateCommand can be dangerous
to mix. If you try set the
textVariable to something that the
validateCommand will not accept it will be set back to the value of the
entry widget. Using the
textVariable for read-only purposes will never
cause problems.
The
validateCommand will turn itself off by setting
validate to
none when an error occurs, for example when the
validateCommand
or
invalidCommand encounters an error in its script while evaluating,
or
validateCommand does not return a valid boolean value.
With the perl/Tk version
validate option is supposed to be
"suspended" while executing the
validateCommand or the
invalidCommand. This is experimental but in theory either callback can
"correct" the value of the widget, and override the proposed change.
(
validateCommand should still return false to inhibit the change from
happening when it returns.)
The
Entry method creates a widget object. This object supports the
configure and
cget methods described in Tk::options which can be
used to enquire and modify the options described above. The widget also
inherits all the methods provided by the generic Tk::Widget class.
Many of the additional methods for entries take one or more indices as
arguments. An index specifies a particular character in the entry's string, in
any of the following ways:
- number
- Specifies the character as a numerical index, where 0
corresponds to the first character in the string.
- anchor
- Indicates the anchor point for the selection, which is set
with the selectionFrom and selectionAdjust methods.
- end
- Indicates the character just after the last one in the
entry's string. This is equivalent to specifying a numerical index equal
to the length of the entry's string.
- insert
- Indicates the character adjacent to and immediately
following the insertion cursor.
- sel.first
- Indicates the first character in the selection. It is an
error to use this form if the selection isn't in the entry window.
- sel.last
- Indicates the character just after the last one in the
selection. It is an error to use this form if the selection isn't in the
entry window.
- @number
- In this form, number is treated as an x-coordinate
in the entry's window; the character spanning that x-coordinate is used.
For example, `` @0'' indicates the left-most
character in the window.
Abbreviations may be used for any of the forms above, e.g. ``
e'' or ``
sel.f''. In general, out-of-range indices are automatically rounded to
the nearest legal value.
The following additional methods are available for entry widgets:
- $entry->bbox(index)
- Returns a list of four numbers describing the bounding box
of the character given by index. The first two elements of the list
give the x and y coordinates of the upper-left corner of the screen area
covered by the character (in pixels relative to the widget) and the last
two elements give the width and height of the character, in pixels. The
bounding box may refer to a region outside the visible area of the
window.
- $entry->cget(?option?)
- Returns the current value of the configuration option given
by option. Option may have any of the values accepted by the
entry command.
- $entry->configure(?option?,
? value, option, value, ...?)
- Query or modify the configuration options of the widget. If
no option is specified, returns a list describing all of the
available options for $entry (see Tk::configure for information on the
format of this list). If option is specified with no value,
then the command returns a list describing the one named option (this list
will be identical to the corresponding sublist of the value returned if no
option is specified). If one or more option-value pairs are
specified, then the command modifies the given widget option(s) to have
the given value(s); in this case the command returns an empty string.
Option may have any of the values accepted by the entry
command.
- $entry->delete(first,
? last?)
- Delete one or more elements of the entry. First is
the index of the first character to delete, and last is the index
of the character just after the last one to delete. If last isn't
specified it defaults to first+1, i.e. a single character is
deleted. This method returns an empty string.
- $entry->get
- Returns the entry's string.
- $entry->icursor(index)
- Arrange for the insertion cursor to be displayed just
before the character given by index. Returns an empty string.
- $entry->index(index)
- Returns the numerical index corresponding to
index.
- $entry->insert(index,
string)
- Insert the characters of string just before the
character indicated by index. Returns an empty string.
- $entry->scan(option,
args)
- $entry->scanOption(args)
- This method is used to implement scanning on entries. It
has two forms, depending on Option:
- $entry->scanMark(x)
- Records x and the current view in the entry widget;
used in conjunction with later scanDragto methods. Typically this
method is associated with a mouse button press in the widget. It returns
an empty string.
- $entry->scanDragto(x)
- This method computes the difference between its x
argument and the x argument to the last scanMark method for
the widget. It then adjusts the view left or right by 10 times the
difference in x-coordinates. This method is typically associated with
mouse motion events in the widget, to produce the effect of dragging the
entry at high speed through the widget. The return value is an empty
string.
- $entry->selection(option,
arg)
- $entry->selectionOption(arg)
- This method is used to adjust the selection within an
entry. It has several forms, depending on Option:
- $entry->selectionAdjust(index)
- Locate the end of the selection nearest to the character
given by index, and adjust that end of the selection to be at
index (i.e including but not going beyond index). The other
end of the selection is made the anchor point for future
selectionTo methods. If the selection isn't currently in the entry,
then a new selection is created to include the characters between
index and the most recent selection anchor point, inclusive.
Returns an empty string.
- $entry->selectionClear
- Clear the selection if it is currently in this widget. If
the selection isn't in this widget then the method has no effect. Returns
an empty string.
- $entry->selectionFrom(index)
- Set the selection anchor point to just before the character
given by index. Doesn't change the selection. Returns an empty
string.
- $entry->selectionPresent
- Returns 1 if there is are characters selected in the entry,
0 if nothing is selected.
- $entry->selectionRange(start,
end)
- Sets the selection to include the characters starting with
the one indexed by start and ending with the one just before
end. If end refers to the same character as start or
an earlier one, then the entry's selection is cleared.
- $entry->selectionTo(index)
- If index is before the anchor point, set the
selection to the characters from index up to but not including the
anchor point. If index is the same as the anchor point, do nothing.
If index is after the anchor point, set the selection to the
characters from the anchor point up to but not including index. The
anchor point is determined by the most recent selectionFrom or
selectionAdjust method in this widget. If the selection isn't in
this widget then a new selection is created using the most recent anchor
point specified for the widget. Returns an empty string.
- $entry->validate
- This command is used to force an evaluation of the
validateCommand independent of the conditions specified by the
validate option. It returns 0 or 1.
- $entry->xview(args)
- This command is used to query and change the horizontal
position of the text in the widget's window. It can take any of the
following forms:
- $entry->xview
- Returns a list containing two elements. Each element is a
real fraction between 0 and 1; together they describe the horizontal span
that is visible in the window. For example, if the first element is .2 and
the second element is .7, 20% of the entry's text is off-screen to the
left, the middle 50% is visible in the window, and 30% of the text is
off-screen to the right. These are the same values passed to scrollbars
via the -xscrollcommand option.
- $entry->xview(index)
- Adjusts the view in the window so that the character given
by index is displayed at the left edge of the window.
- $entry->xviewMoveto(fraction)
- Adjusts the view in the window so that the character
fraction of the way through the text appears at the left edge of
the window. Fraction must be a fraction between 0 and 1.
- $entry->xviewScroll(number,
what)
- This method shifts the view in the window left or right
according to number and what. Number must be an
integer. What must be either units or pages or an
abbreviation of one of these. If what is units, the view
adjusts left or right by number average-width characters on the
display; if it is pages then the view adjusts by number
screenfuls. If number is negative then characters farther to the
left become visible; if it is positive then characters farther to the
right become visible.
DEFAULT BINDINGS¶
Tk automatically creates class bindings for entries that give them the following
default behavior. In the descriptions below, ``word'' refers to a contiguous
group of letters, digits, or ``_'' characters, or any single character other
than these.
- [1]
- Clicking mouse button 1 positions the insertion cursor just
before the character underneath the mouse cursor, sets the input focus to
this widget, and clears any selection in the widget. Dragging with mouse
button 1 strokes out a selection between the insertion cursor and the
character under the mouse.
- [2]
- Double-clicking with mouse button 1 selects the word under
the mouse and positions the insertion cursor at the beginning of the word.
Dragging after a double click will stroke out a selection consisting of
whole words.
- [3]
- Triple-clicking with mouse button 1 selects all of the text
in the entry and positions the insertion cursor before the first
character.
- [4]
- The ends of the selection can be adjusted by dragging with
mouse button 1 while the Shift key is down; this will adjust the end of
the selection that was nearest to the mouse cursor when button 1 was
pressed. If the button is double-clicked before dragging then the
selection will be adjusted in units of whole words.
- [5]
- Clicking mouse button 1 with the Control key down will
position the insertion cursor in the entry without affecting the
selection.
- [6]
- If any normal printing characters are typed in an entry,
they are inserted at the point of the insertion cursor.
- [7]
- The view in the entry can be adjusted by dragging with
mouse button 2. If mouse button 2 is clicked without moving the mouse, the
selection is copied into the entry at the position of the mouse
cursor.
- [8]
- If the mouse is dragged out of the entry on the left or
right sides while button 1 is pressed, the entry will automatically scroll
to make more text visible (if there is more text off-screen on the side
where the mouse left the window).
- [9]
- The Left and Right keys move the insertion cursor one
character to the left or right; they also clear any selection in the entry
and set the selection anchor. If Left or Right is typed with the Shift key
down, then the insertion cursor moves and the selection is extended to
include the new character. Control-Left and Control-Right move the
insertion cursor by words, and Control-Shift-Left and Control-Shift-Right
move the insertion cursor by words and also extend the selection.
Control-b and Control-f behave the same as Left and Right, respectively.
Meta-b and Meta-f behave the same as Control-Left and Control-Right,
respectively.
- [10]
- The Home key, or Control-a, will move the insertion cursor
to the beginning of the entry and clear any selection in the entry.
Shift-Home moves the insertion cursor to the beginning of the entry and
also extends the selection to that point.
- [11]
- The End key, or Control-e, will move the insertion cursor
to the end of the entry and clear any selection in the entry. Shift-End
moves the cursor to the end and extends the selection to that point.
- [12]
- The Select key and Control-Space set the selection anchor
to the position of the insertion cursor. They don't affect the current
selection. Shift-Select and Control-Shift-Space adjust the selection to
the current position of the insertion cursor, selecting from the anchor to
the insertion cursor if there was not any selection previously.
- [13]
- Control-/ selects all the text in the entry.
- [14]
- Control-\ clears any selection in the entry.
- [15]
- The F16 key (labelled Copy on many Sun workstations) or
Meta-w copies the selection in the widget to the clipboard, if there is a
selection.
- [16]
- The F20 key (labelled Cut on many Sun workstations) or
Control-w copies the selection in the widget to the clipboard and deletes
the selection. If there is no selection in the widget then these keys have
no effect.
- [17]
- The F18 key (labelled Paste on many Sun workstations) or
Control-y inserts the contents of the clipboard at the position of the
insertion cursor.
- [18]
- The Delete key deletes the selection, if there is one in
the entry. If there is no selection, it deletes the character to the right
of the insertion cursor.
- [19]
- The BackSpace key and Control-h delete the selection, if
there is one in the entry. If there is no selection, it deletes the
character to the left of the insertion cursor.
- [20]
- Control-d deletes the character to the right of the
insertion cursor.
- [21]
- Meta-d deletes the word to the right of the insertion
cursor.
- [22]
- Control-k deletes all the characters to the right of the
insertion cursor.
- [23]
- Control-t reverses the order of the two characters to the
right of the insertion cursor.
If the entry is disabled using the -state option, then the entry's
view can still be adjusted and text in the entry can still be selected,
but no insertion cursor will be displayed and no text modifications will
take place.
The behavior of entries can be changed by defining new bindings for
individual widgets or by redefining the class bindings.
KEYWORDS¶
entry, widget
