3.48 text-field%

► |  | The Racket Graphical Interface Toolkit

1 | Windowing
2 | Widget Gallery
3 | Windowing Classes
4 | Windowing Functions
5 | Editors
6 | Snip and Style Classes
7 | Editor Classes
8 | Editor Functions
9 | WXME Decoding
10 | Preferences
11 | Dynamic Loading
12 | Startup Actions
13 | Platform Dependencies
| Index

▼ | 3 | Windowing Classes

3.1 | area<%>
3.2 | area-container<%>
3.3 | area-container-window<%>
3.4 | button%
3.5 | canvas<%>
3.6 | canvas%
3.7 | check-box%
3.8 | checkable-menu-item%
3.9 | choice%
3.10 | clipboard-client%
3.11 | clipboard<%>
3.12 | combo-field%
3.13 | control<%>
3.14 | column-control-event%
3.15 | control-event%
3.16 | cursor%
3.17 | dialog%
3.18 | event%
3.19 | frame%
3.20 | gauge%
3.21 | group-box-panel%
3.22 | grow-box-spacer-pane%
3.23 | horizontal-pane%
3.24 | horizontal-panel%
3.25 | key-event%
3.26 | labelled-menu-item<%>
3.27 | list-box%
3.28 | list-control<%>
3.29 | menu%
3.30 | menu-bar%
3.31 | menu-item<%>
3.32 | menu-item%
3.33 | menu-item-container<%>
3.34 | message%
3.35 | mouse-event%
3.36 | pane%
3.37 | panel%
3.38 | popup-menu%
3.39 | printer-dc%
3.40 | radio-box%
3.41 | selectable-menu-item<%>
3.42 | separator-menu-item%
3.43 | scroll-event%
3.44 | slider%
3.45 | subarea<%>
3.46 | subwindow<%>
3.47 | tab-panel%
3.48 | text-field%
3.49 | timer%
3.50 | top-level-window<%>
3.51 | vertical-pane%
3.52 | vertical-panel%
3.53 | window<%>

On this page:

new
get-editor
get-field-background
get-value
set-field-background
set-value

Inherited methods:
from control<%>
command
from subwindow<%>
reparent
from window<%>
accept-drop-files
client->screen
enable
focus
get-client-handle
get-client-size
get-cursor
get-handle
get-height
get-label
get-plain-label
get-size
get-width
get-x
get-y
has-focus?
is-enabled?
is-shown?
on-drop-file
on-focus
on-move
on-size
on-subwindow-char
on-subwindow-event
on-subwindow-focus
on-superwindow-enable
on-superwindow-show
popup-menu
refresh
screen->client
set-cursor
set-label
show
warp-pointer
from area<%>
get-graphical-min-size
get-parent
get-top-level-window
min-height
min-width
stretchable-height
stretchable-width
from subarea<%>
horiz-margin
vert-margin

top ← prev up next →

class text-field% : class?
superclass: object%
extends: | control<%>

A text-field% object is an editable text field with an optional label displayed in front of it. There are two text field styles:

- A single line of text is visible, and a special control event is generated when the user presses Return or Enter (when the text field has the focus) and the event is not handled by the text field’s frame or dialog (see on-traverse-char in top-level-window<%> ).

- Multiple lines of text are visible, and Enter is not handled specially.

Whenever the user changes the content of a text field, its callback procedure is invoked. A callback procedure is provided as an initialization argument when each text field is created.

The text field is implemented using a text% editor (with an inaccessible display). Thus, whereas text-field% provides only get-value and set-value to manipulate the text in a text field, the get-editor returns the field’s editor, which provides a vast collection of methods for more sophisticated operations on the text.

The keymap for the text field’s editor is initialized by calling the current keymap initializer procedure, which is determined by the current-text-keymap-initializer parameter.

> > constructor
> > (new text-field% |
> > |  | [label label] |
> > |  | [parent parent] |
> > | [ | [callback callback] |
> > |  | [init-value init-value] |
> > |  | [style style] |
> > |  | [font font] |
> > |  | [enabled enabled] |
> > |  | [vert-margin vert-margin] |
> > |  | [horiz-margin horiz-margin] |
> > |  | [min-width min-width] |
> > |  | [min-height min-height] |
> > |  | [stretchable-width stretchable-width] |
> > |  | [stretchable-height stretchable-height]]) |
> → (is-a?/c text-field%)
> label : (or/c label-string? #f)
> | parent |  | : |  |
> (or/c (is-a?/c frame%) (is-a?/c dialog%)
> (is-a?/c panel%) (is-a?/c pane%))
> | callback |  | : |  |
> ((is-a?/c text-field%) (is-a?/c control-event%)
> . -> . any)
> |  |  | = |  | (lambda (t e) (void))
> init-value : string? = ""
> | style |  | : |  |
> (listof (or/c 'single 'multiple 'hscroll 'password
> 'vertical-label 'horizontal-label
> 'deleted))
> |  |  | = |  | '(single)
> font : (is-a?/c font%) = normal-control-font
> enabled : any/c = #t
> vert-margin : spacing-integer? = 2
> horiz-margin : spacing-integer? = 2
> min-width : (or/c dimension-integer? #f) = #f
> min-height : (or/c dimension-integer? #f) = #f
> stretchable-width : any/c = #t
> stretchable-height : any/c = (memq 'multiple style)

If label is not #f, it is used as the text field label. Otherwise, the text field does not display its label.

If & occurs in label, it is specially parsed as for button%.

The callback procedure is called when the user changes the text in the text field or presses the Enter key (and Enter is not handled by the text field’s frame or dialog; see on-traverse-char in top-level-window<%>). If the user presses Enter, the type of event passed to the callback is 'text-field-enter, otherwise it is 'text-field.

If init-value is not "", the graphical minimum size for the text item is made wide enough to show init-value. Otherwise, a built-in default width is selected. For a text field in single-line mode, the graphical minimum size is set to show one line, and only the control’s width is stretchable by default. For a multiple-line text field, the graphical minimum size shows three lines of text, and it is stretchable in both directions by default.

The style must contain exactly one of 'single or 'multiple; the former specifies a single-line field and the latter specifies a multiple-line field. The 'hscroll style applies only to multiple-line fields; when 'hscroll is specified, the field has a horizontal scrollbar and autowrapping is disabled; otherwise, the field has no horizontal scrollbar and autowrapping is enabled. A multiple-line text field always has a vertical scrollbar. The 'password style indicates that the field should draw each character of its content using a generic symbol instead of the actual character. If style includes 'vertical-label, then the text field is created with a label above the control; if style does not include 'vertical-label (and optionally includes 'horizontal-label), then the label is created to the left of the text field. If style includes 'deleted, then the text field is created as hidden, and it does not affect its parent’s geometry; the text field can be made active later by calling parent’s add-child method..

The font argument determines the font for the control. For information about the enabled argument, see window<%>. For information about the horiz-margin and vert-margin arguments, see subarea<%>. For information about the min-width, min-height, stretchable-width, and stretchable-height arguments, see area<%>.

> method (send a-text-field get-editor) → (is-a?/c text%)

Returns the editor used to implement the text field.

For a text field, the most useful methods of a text% object are the following:

- (send a-text get-text) returns the current text of the editor.

- (send a-text erase) deletes all text from the editor.

- (send a-text insert str) inserts str into the editor at the current caret position.

> method (send a-text-field get-field-background) → (is-a?/c color%)

Gets the background color of the field’s editable area.

> method (send a-text-field get-value) → string?

Returns the text currently in the text field.

> method (send a-text-field set-field-background color) → void?
> color : (is-a?/c color%)

Sets the background color of the field’s editable area.

> method (send a-text-field set-value val) → void?
> val : string?

Sets the text currently in the text field. (The control’s callback procedure is not invoked.)

A text field’s value can be changed by the user typing into the control, and such changes do not go through this method; use the control callback procedure (provided as an initialization argument) to monitor value changes.
top ← prev up next →