gvarbrowser {gWidgets2} | R Documentation

## Constructor for workspace variable browser

### Description

A workspace browser widget. The workspace browser displays values in the global environment. Displayed objects are shown in categories.

generic for toolkit dispatch

Return selected objects a string (when `drop=TRUE`) with recursive values separated by `$`, or the objects themselves (when `drop=FALSE`).

### Usage

    gvarbrowser(handler = NULL, action = "summary", container = NULL, ...,
      toolkit = guiToolkit())

    .gvarbrowser(toolkit, handler = NULL, action = "summary",
      container = NULL, ...)

    ## S3 method for class 'GVarBrowser'
    svalue(obj, index = FALSE, drop = TRUE, ...)

### Arguments

`handler` | A handler assigned to the default change signal. Handlers are called when some event triggers a widget to emit a signal. For each widget some default signal is assumed, and handlers may be assigned to that through `addHandlerChanged` or at construction time. Handlers are functions whose first argument, `h` in the documentation, is a list with atleast two components `obj`, referring to the object emitting the signal and `action`, which passes in user-specified data to parameterize the function call. Handlers may also be added via `addHandlerXXX` methods for the widgets, where `XXX` indicates the signal, with a default signal mapped to `addHandlerChanged` (cf. `addHandler` for a listing). These methods pass back a handler ID that can be used with `blockHandler` and `unblockHandler` to suppress temporarily the calling of the handler.
`action` | User supplied data passed to the handler when it is called
`container` | A parent container. When a widget is created it can be incorporated into the widget heirarchy by passing in a parent container at construction time. (For some toolkits this is not optional, e.g. gWidgets2tcltk or gWidgets2WWW2.)
`...` | These values are passed to the `add` method of the parent container. Examples of values are `expand`, `fill`, and `anchor`, although they're not always supported by a given widget. For more details see add. Occasionally the variable arguments feature has been used to sneak in hidden arguments to toolkit implementations. For example, when using a widget as a menubar object one can specify a parent argument to pass in parent information, similar to how the argument is used with gaction and the dialogs.
`toolkit` | Each widget constructor is passed in the toolkit it will use. This is typically done using the default, which will lookup the toolkit through `guiToolkit`.
`obj` | object of method call
`index` | NULL or logical. If `TRUE` and widget supports it an index, instead of a value will be returned.
`drop` | NULL or logical. If widget supports it, drop will work as it does in a data frame or perhaps someother means.

### Details

For defining the categories, the reference method `set_filter_classes` takes a named list, the names defining the categories, the values being the classes belonging to that category. Non categorized values appear separately. The default is defined in `gWidgets2:::gvarbrowser_default_classes`.

The variable browser uses an instance of `WSWatcherModel` to monitor the global workspace. This instance may be useful for other purposes. (For example, one may add an observer that is called to listen for changes to the set of available data frames.). The instance is available through the `ws_model` property.

The `svalue` method returns the selected variable names. If `drop=FALSE` is given, the objects are returned.

The widget should support dragging from without needing to specify a `drag_source`, though this may be overridden.

Use `addHandlerChanged` to listen to activation of a variable (double clicking). Use `addHandlerSelectionChanged` to monitor change of selection.

[Package gWidgets2 version 1.0-8 Index]