gtable: A table widget

In jverzani/gWidgetsWWW2: Toolkit implementation of the gWidgets API for use with web pages

Description

A widget for displaying a data frame in tabular format. The main property is the set of indices for the currently selected rows. For large data sets, the data can be "paged", that is given to the browser in bite-sized chunks so the lag is lacking. The change handler is for a single click, also used for selection. Use addHandlerDoubleclick to specify a callback for the double click event on a cell.

The table widget is implemented using a proxy. That is, the data is loaded in a separate AJAX call. This makes things relatively responsive, but if there is too much data one can turn on paging.

Usage

gtable(items, multiple = FALSE, chosencol = 1, icon.FUN = NULL,
  filter.column = NULL, filter.labels = NULL, filter.FUN = NULL,
  handler = NULL, action = NULL, container = NULL, ..., width = NULL,
  height = NULL, ext.args = NULL, paging = FALSE, col.widths = rep(20,
  ncol(as.data.frame(items))))

Arguments

items	data frame of items to display
multiple	logical. TRUE for multiple selections
chosencol	The svalue() method returns a single value, by default. This species column of that value.
icon.FUN	NOT IMPLEMENTED. Instead, just add a column with class Icon containing css class of the icons
filter.column	Ignored
filter.labels	Ignored
filter.FUN	Ignored.
handler	single click handlers
action	Passed to handler to parameterize a call
container	A parent container. In gWidgetsWWW2 a parent container is not optional (though it can be substituted with the parent argument in some circumstances). The parent specifies the widget heirarchy and the ... argument is used to pass along arguments to layout the child component in the parent container. Typically, these are passed to the add method of the parent container.
...	Used to pass along argument to the parent container's add method and possible other arguments to the underlying ference class constructors.
width	width in pixels of component. Sizing in gWidgetsWWW2 is sometimes necessary as the arguments expand and fill are not well implemented.
height	height in pixels of the component.
ext.args	additional configuration values to pass to constructor
paging	Either a logical variable or integer. If TRUE then paging will be used which allows only chunks of the data to be sent to the browser at a time (default size = 200 rows). If integer then paging is turned on and this value overrides the default page size.
col.widths	width of each column. Also see size<- with a list where columnWidths is specified.

Details

The column names are inherited from the columnnames of the data frame.

A column of class "Icon" (see asIcon) will render a css class as an icon. See the example.

The item replacement operator [<- will work only if all the column types remain constant, as the column renderers are set at time of construction. This also effects the initial data frame. Pass a 0-row data frame with column names and defined column types at construction if no data is known at that point.

The widget can filter through the visible method. This basically passes back the filtered data from the server each time it is called. To avoid the data transfer, one can use the filter reference method, which filters browser side by a regular expression.

Value

An ExtWidget instance

Methods

filter(colname, regex)

Use filter by regular expression. No visible<- method to adjust visible rows

get_value(...)

Get main property, Can't query widget, so we store here

param_defn(signal)

Define different parameter definitions based on the signal

process_transport(value, ...)

R Function to process the transport. Typically just sets 'value', but may do more. In the above example, where var param = value: this.getText() was from transport_fun we would get the text for value

set_value(value, ...)

Set main property, invoke change handler on change

transport_fun()

javascript function for transport web -> R. Creates an object param. This is a string to be passed to the javascript queue withing the transport function call E.g. var param = value: this.getText()

Note

With width and/or height set to NULL, the default size will likely be unsatisfying. (And can consume any space in a box, so items packed in after will not be shown.) As such, these values are often best set by the programmer. They can be readjusted through the size<- method. The size<- method can also be used to adjust the columns widths, by passing a list with a component named columnWidths containing the desired widths in pixels.

The visible<- method may be used for filtering.

Examples

w <- gwindow("Filtering and table example")
sb <- gstatusbar("Powered by gWidgetsWWW and Rook", cont=w)
g <- ggroup(cont=w, horizontal=FALSE)
g1 <- ggroup(cont=g)
glabel("Filter by:", cont=g1)
e <- gedit("", cont=g1)
tbl <- gtable(data.frame(name=state.name, stringsAsFactors=FALSE), cont=g,  multiple=TRUE)
addHandlerKeystroke(e, handler=function(h,...) {
val <- svalue(h$obj)
if(nchar(val) > 0) {
tbl$filter("name", val)
}
})
b <- gbutton("click", cont=g, handler=function(h,...) galert(svalue(tbl, index=FALSE), parent=w))

## icons
m <- mtcars[1:3, 1:4]
## add icons as css class
m[,1] <- asIcon(c("up","up","down"))
 gtable(m, cont=g)

jverzani/gWidgetsWWW2 documentation built on Feb. 9, 2020, 5:18 p.m.