[R] intermediate action button necessary to update graph-not responding

Clarkson, Christopher christopher.clarkson15 at imperial.ac.uk
Tue May 10 15:23:27 CEST 2016

I'm aware that this is not a suitable question for this resource but neither Stackoverflow nor shiny help forum could help with the problem I'm having- is it possible that you could point me in the right direction?

I have a command from a particular package that outputs a graph. The command requires preliminary processed input via a different command that is defined in the same package. Hence my plan is to create an app whereby the user can interactively update the map. This as far as I can see will require 2 action buttons: "actionbutton A" will re-run the preliminary processing command with input from a "checkboxGroupInput". "actionbutton B" will then update the graph with the new input from the preliminary processing command.

checkboxGroupInput("column_choices", "column choice", colnames(data), selected=c("column1", "column2"....)),
actionButton(inputId="choices", label="Update tag"))

actionButton(inputId="replot", label="Update plot")),

servercell <- function(input, output) {
  dataInput<-observeEvent(input$choices, {
    isolate(tagData(IRIS[, input$column_choices]))
    isolate(package_defined_plot_function(data=data, dataTag=dataInput()))

The buttons work when tested independent of each other: the checkbox input seems to update fine, after clicking "Update tag"/actionbutton A and the graph seems to work fine after clicking "Update plot"/actionbutton B (when dataInput() is not an argument in the plot function).

My problem is that dataInput<-observeEvent(input$choices, {..... does not allow the graph to display. When dataInput() is made an argument of the plotting function- instead of the graph displaying on the app page- in place of that I get the error: could not find dataInput function

As I said buttons A and B work fine when independent of each other..... however their coexistence conflicts... and having two action buttons is the only way I can think of to update the graph interactively... if anyone can think of how to do it with one button that would be great.

When I do this with one output command, :
package_defined_plot_function(data=data, dataTag=tagData(runif(input$cell_choices(isolate())))
I try some variation(cannot remember the actual syntax) of the above but it forces me to shut down my R session as the data handling seems to go on an infinite loop (I can not show you the exact error for this as in order to get it I have to crash the R session- it looks some thing like: "cannot compute -Inf"). hence I would be much more comfortable with tow buttons.
I am quite stuck as I don't know what to do... any tips?

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