在 R Shiny App 中无法正常工作

Question

我试图在单击按钮后显示一个绘图图表，这意味着该图表只会在单击按钮时显示，但该图表只是没有显示......这有什么线索吗？代码如下：

shinyApp(
  ui = fluidPage(
    sidebarLayout(
      sidebarPanel(
        actionButton("button", "Show Chart")
      ),
      mainPanel(
        plotOutput("bar")
      )
    )
  ),
  server = function(input, output) {
    observeEvent(input$button, {
      category <- c('task1', 'task2', 'task2','task1','task1')
      start_min <- c(0, 0, 16, 45, 40)
      stop_min <- c(14.9,18.8,17.5,65.5, 70)
      group <- c('A', 'B', 'A', 'A', 'B')
      data <- data.frame(category,start_min,stop_min,group)
      
      task_bars <- ggplot(data, mapping=aes(ymin=0, ymax=1,
                                            xmin=start_min, xmax=stop_min,
                                            fill=as.factor(category),
                                            text=paste("Task:", str_wrap(string = category, width = 70,),
                                                       "<br>Start: ", format(start_min, digits=1), "min", 
                                                       "<br>Stop: ", format(stop_min, digits=1), "min")
      )) +
        geom_rect(alpha=0.8) +
        theme_minimal()+
        theme(
          axis.title.x=element_text(color="white"), axis.text.x=element_text(color="white"),
          axis.text.y=element_blank(), axis.ticks.y=element_blank(),
          panel.grid.major = element_blank(), panel.grid.minor = element_blank(),
          panel.border = element_blank(), panel.background = element_blank()) +
        scale_fill_discrete(breaks=data$category)
      
      task_bars <- plotly::ggplotly(task_bars, tooltip="text", width = 970, height = 120) %>%
        plotly::config(displayModeBar = TRUE) %>% 
        plotly::layout(plot_bgcolor='black', paper_bgcolor='black', margin = list(b=30, l=0, r=10, t=30))
      
      print(task_bars)
      output$bar <- renderPlotly(task_bars)
    })
  }
)

Answer 1

您需要将output$bar 移出observeEvent。我为您的绘图创建了一个 reactiveValues 对象。 observeEvent 创建绘图，然后将其显示在输出中。

您还在 ui 中使用 plotOutput 而不是在 ui 中使用 plotlyOutput。

library(shiny)
library(ggplot2)
library(plotly)

task_bars <- reactiveValues(plot = NULL)

shinyApp(
  ui = fluidPage(
    sidebarLayout(
      sidebarPanel(
        actionButton("button", "Show Chart")
      ),
      mainPanel(
        plotlyOutput("bar")
      )
    )
  ),
  server = function(input, output) {
    observeEvent(input$button, {
      category <- c('task1', 'task2', 'task2','task1','task1')
      start_min <- c(0, 0, 16, 45, 40)
      stop_min <- c(14.9,18.8,17.5,65.5, 70)
      group <- c('A', 'B', 'A', 'A', 'B')
      data <- data.frame(category,start_min,stop_min,group)
      
      task_bars$plot <- ggplot(data, mapping=aes(ymin=0, ymax=1,
                                            xmin=start_min, xmax=stop_min,
                                            fill=as.factor(category)
      )) +
        geom_rect(alpha=0.8) +
        theme_minimal()+
        theme(
          axis.title.x=element_text(color="white"), axis.text.x=element_text(color="white"),
          axis.text.y=element_blank(), axis.ticks.y=element_blank(),
          panel.grid.major = element_blank(), panel.grid.minor = element_blank(),
          panel.border = element_blank(), panel.background = element_blank()) +
        scale_fill_discrete(breaks=data$category)

    })
      
    output$bar <- renderPlotly({
if(input$button == 0){
return()
} else {
      print(plotly::ggplotly(task_bars$plot, tooltip="text", width = 970, height = 120) %>%
        plotly::config(displayModeBar = TRUE) %>% 
        plotly::layout(plot_bgcolor='black', paper_bgcolor='black', margin = list(b=30, l=0, r=10, t=30))
      )
}
    })
  }
)