r - 如何在 Shiny 仪表板中创建条件渲染 UI
问题描述
我无法通过 renderMenu 创建条件侧边栏菜单,因为 if 语句失败。“警告:如果:参数长度为零时出错”。
我在 Shiny 仪表板中找到了有条件的 RenderUI R Shiny和Conditional 面板,但两者都不是我想要的。在这种情况下,条件面板可能会起作用,但从长远来看,我需要能够在服务器端执行此操作。
if (interactive()) {
library(ggplot2)
library(shiny)
library(shinydashboard)
library(shinipsum)
ui <- dashboardPage(
header = dashboardHeader(),
dashboardSidebar(
sidebarMenuOutput("plotDataVHA"),
sidebarMenuOutput("tabSelector")
),
dashboardBody(tabItems(
tabItem(tabName = "facilities",
fluidRow(box(
uiOutput("selectedFacilityTime")
))),
tabItem(tabName = "service",
fluidRow(box(
uiOutput("selectedFacilityYyCases")
)))
))
)
server <- function(input, output) {
output$renderedSelectedFacilityTime <- renderPlot({
random_ggplot(type = "line")
})
output$selectedFacilityTime <- renderUI({
plotOutput("renderedSelectedFacilityTime")
})
output$renderedFacilityYyCases <- renderPlot({
random_ggplot(type = "bar")
})
output$selectedFacilityYyCases <- renderUI({
plotOutput("renderedFacilityYyCases")
})
output$tabSelector <- renderMenu({
sidebarMenu(id = "test",
menuItem(
text = "Chart data",
menuSubItem(
text = "Facilities",
tabName = "facilities",
selected = TRUE
),
menuSubItem(
text = "Service & Specialty",
tabName = "service",
icon = NULL
)
))
})
output$plotDataVHA <- renderMenu({
if (input$test == "facilities") {
sidebarMenu(
menuItem(
text = "VHA data",
menuSubItem(
text = "None",
selected = TRUE,
icon = NULL
),
menuSubItem(text = "Mean", icon = NULL)
)
)
}
})
}
shinyApp(ui, server)
}
正常工作时,菜单“VHA 数据”应仅在选择子菜单“设施”时可见。
解决方案
有趣的问题。您收到argument is of length zero
错误的原因是因为您在服务器端通过renderMenu()
. 因此,当应用程序启动时,input$test
没有分配给它的值。您可以通过使用which will仅在启动后req()
评估测试来避免这种情况。input$test == "facilities"
input$test
现在菜单仅在选择另一个子菜单时出现,您希望创建独立于renderMenu()
. 最好在正常情况下评估条件,reactive()
然后将此反应函数作为输入传递给renderMenu()
. input$test == "facilities"
最后,要在is时移除菜单FALSE
,可以渲染一个空的 html 容器。
这是更新的代码:
library(ggplot2)
library(shiny)
library(shinydashboard)
library(shinipsum)
ui <- dashboardPage(
header = dashboardHeader(),
dashboardSidebar(
sidebarMenuOutput("plotDataVHA"),
sidebarMenuOutput("tabSelector")
),
dashboardBody(tabItems(
tabItem(tabName = "facilities",
fluidRow(box(
uiOutput("selectedFacilityTime")
))),
tabItem(tabName = "service",
fluidRow(box(
uiOutput("selectedFacilityYyCases")
)))
))
)
server <- function(input, session, output) {
output$renderedSelectedFacilityTime <- renderPlot({
random_ggplot(type = "line")
})
output$selectedFacilityTime <- renderUI({
plotOutput("renderedSelectedFacilityTime")
})
output$renderedFacilityYyCases <- renderPlot({
random_ggplot(type = "bar")
})
output$selectedFacilityYyCases <- renderUI({
plotOutput("renderedFacilityYyCases")
})
output$tabSelector <- renderMenu({
sidebarMenu(id = "test",
menuItem(
text = "Chart data",
menuSubItem(
text = "Facilities",
tabName = "facilities",
selected = TRUE
),
menuSubItem(
text = "Service & Specialty",
tabName = "service",
selected = FALSE,
icon = NULL
)
))
})
make_menu <- reactive({
cat("Current submenu selected: ", input$test, "\n\n")
if (req(input$test) == "facilities") {
sidebarMenu(
menuItem(
text = "VHA data",
menuSubItem(
text = "None",
selected = TRUE,
icon = NULL
),
menuSubItem(text = "Mean", icon = NULL)
)
)
} else {
# return an empty HTML container
div()
}
})
output$plotDataVHA <- renderMenu({
make_menu()
})
}
shinyApp(ui, server)