Description Usage Arguments Details See Also Examples
A combobox allows selection of a value from a list of items using a popup menu. Additionally, the widget can combine a text entry widget for user input outside of the pre-set list of items. A combobox is useful for selection from a moderate size of items (2-30, say). For smaller sets of items, a radio button group is a possibility, for larger sets of items, a scrollable (and perhaps searchable) table may be preferred.
1 2 3 4 5 |
items |
Vector of values to select from. This may also be a data frame, in which case the first column is the vector of values, the second (if present) indicates a stock icon to display with the item (not all toolkits), and the third (if present) will indicate a tooltip to display (not all toolkits). |
selected |
For gradio the initial selected value (as an index) For a drop list, the first selected value. Use 0 to leave blank |
editable |
A logical indicating if the user can add an entry to the list of available answers |
coerce.with |
Apply this function to selected value before returning |
handler |
Called when selection is changed |
action |
Passed to handler when called. |
container |
Optional container to attach widget to |
... |
Passed to |
toolkit |
Which GUI toolkit to use |
The initial items
can be a vector or a data frame. Not
all tool kits do something with the extra columns in the data
frame.
The svalue
method returns the selected value by
name. Assume the value is a character vector. Use the
coerce.with
argument to return a value of a different
type. If the extra argument index=TRUE
is specified,
the index of the selected value is given.
The svalue<-
method can be used to set the selected
value. This is done my name or if the argument
index=TRUE
is given by index. The value can be a data
frame, in which case the first column is used to match against
the current items.
The "["
method refers to the vector defining the items.
The "[<-"
method can be used to change the vector
defining the items.
The "length"
method returns the number of items.
For gcombobox
the argument editable=TRUE
adds a
text-edit box where the user can type in a selection. By
default this value is returned as a character by
svalue
. Use coerce.with
to coerce this prior to returning.
A combobox is one of several ways to select a value of a set of items. See also
gcheckbox
,
gradio
,
gcheckboxgroup
, and
gtable
.
Methods for gComponent objects are detailed in gWidgets-methods
.
Event Handlers are detailed in gWidgets-handlers
.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | ## Not run:
flavors <- c("vanilla", "chocolate", "strawberry")
f <- function(h,...) print(
paste("Yum",
paste(svalue(h$obj),collapse=" and "),
sep = " "))
w <- gwindow("combobox example")
gp <- ggroup(container=w)
glabel("Favorite flavor:", container=gp)
cb <- gcombobox(flavors, editable=TRUE, container=gp, handler=f)
svalue(cb) <- "vanilla"
svalue(cb)
cbg[3] <- "raspberry"
## End(Not run)
|
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