我正在设计一个包含 plotly 散点图的 Shiny 应用程序.我希望用户能够单击图表以使用 event_data 函数记录事件，然后能够通过单击 actionButton.一些示例代码如下所示:

I am designing a Shiny app which contains a plotly scatter plot. I would like for the user to be able to click on the graph to record an event using the event_data function, but then be able to clear that event on the click of an actionButton. Some example code can be seen below:

library(shiny)
library(plotly)

ui <- fluidPage(
  actionButton("clearEvent", label = "clear event"),
  verbatimTextOutput("plotVal"),
  plotlyOutput('plot1')
)

server <- function(input, output, session) {
  output$plot1 <- renderPlotly({
    d <- diamonds[sample(nrow(diamonds), 1000), ]
    plot_ly(d, x = ~carat, y = ~price, color = ~carat,
            size = ~carat, text = ~paste("Clarity: ", clarity))
  })

  output$plotVal <- renderPrint({
    e <- event_data("plotly_click")
    if (is.null(e)) {
      NULL
    } else {
      e
    }
  })

  observeEvent(input[["clearEvent"]], {
    e <- NULL
  })
}

shinyApp(ui = ui, server = server)

但是，这并没有像我预期的那样清除事件.查看 event_data 的代码表明这可能是因为它存储在 session 对象本身中.有什么想法可以覆盖它吗?

This doesn't clear the event like I would expect, however. Looking into the code for event_data shows that this is probably because it is stored within the session object itself. Any ideas how I can overwrite it?

我遇到的唯一类似的事情是 Clear plotly click event 但它非常hacky并且似乎对我不起作用.

The only similar thing I have come across is Clear plotly click event but it's very hacky and doesn't seem to work for me.

推荐答案

在您的示例中，e 只是在 renderPrint 和 observeEvent 而不是全局性的，因此即使 e 在 observeEvent 中更改，它也不会触发 renderPrint 中的任何内容.

In your example, e is just defined in the renderPrint and in the observeEvent and not globally so even if e is changed in the observeEvent, it does not trigger anything in the renderPrint.

您可以为此使用 reactiveValues:

data <- reactiveValues(e=NULL)

  observe({
    data$e <- event_data("plotly_click")
  })

  output$plotVal <- renderPrint({
    e <- data$e
    if (is.null(e)) {
      NULL
    } else {
      e
    }
  })

  observeEvent(input[["clearEvent"]], {
    data$e <- NULL
  })

data$e 每当用户单击绘图或按钮时都会更改，并且由于 renderPrint，每当 data$e 更改时都会更新.