qconnect: Connect a signal handler
In ggobi/qtbase: Interface Between R and 'Qt'

Description Usage Arguments Details Value Author(s) Examples

Like many other GUI toolkits, Qt supports connecting handler functions to signals, which are emitted in response to user actions. The qconnect function connects an R function to a signal on a Qt object.

1	qconnect(x, signal, handler, user.data)

`x`	The Qt object providing the signal
`signal`	The name of the signal
`handler`	The R function to handle the signal
`user.data`	Data to pass to the R function as the last parameter. If omitted, no such argument is passed to the handler.

In Qt, only other QObject instances can listen to a signal, so this function creates a dummy object that invokes the R function upon receipt of the signal.

To disconnect a handler, call the disconnect method on the signal emitter x, passing it the returned dummy QObject; see the example.

A dummy QObject instance that is listening to the signal. Will become invalid when the signal emitter is invalidated.

Michael Lawrence

window <- Qt$QWidget()
button <- Qt$QPushButton(window)
listener <- qconnect(button, "pressed", function(x) print("hello world"))
button$disconnect(listener)