我的目标是建立菜单,其内容是动态生成的,用户只能看到menuItems/menuSubItems从顶部开始到所选择的一个(“next”按钮将用于到达下一个尚未显示的menuItems/menuSubItems;如果选择了任何可用的menuItems/menuSubItems菜单,则应该重新生成菜单,以便选择最后一个可用的menuItems/menuSubItems)。所以我将不得不玩选和startExpanded的论点,但这不是这个问题的一部分。闪亮:闪亮的仪表板中的renderMenu和observeEvent冲突(侧边菜单)
我面临的问题是相互连接renderMenu
和observeEvent
(检查所选menuItem/menuSubItem)。以下是代码:
library(shiny)
library(shinydashboard)
menu_generator <- function(selected = NULL, expanded = NULL){
print("menu_generator")
output <- sidebarMenu(
menuItem("Charts1", icon = icon("bar-chart-o"),
menuSubItem("AAdashboard", tabName = "AAdashboard"),
menuSubItem("BBdashboard", tabName = "BBdashboard")
),
menuItem("Charts2", icon = icon("bar-chart-o"),
menuSubItem("DDdashboard", tabName = "DDdashboard"),
menuSubItem("EWidgets", tabName = "EWidgets")
)
)
return(output)
}
ui <- dashboardPage(
dashboardHeader(title = "Test"),
dashboardSidebar(sidebarMenu(
sidebarMenuOutput("menu_output")
)),
dashboardBody(
tabItems(
tabItem(tabName = "AAdashboard",
h2("ADashboard tab content")
),
tabItem(tabName = "BBdashboard",
h2("BWidgets tab content")
),
tabItem(tabName = "DDdashboard",
h2("DWidgets tab content")
),
tabItem(tabName = "EWidgets",
h2("EWidgets tab content")
)
))
)
server <- function(input, output) {
output$menu_output <- renderMenu({
print("output$menu_output")
sidebarMenu(menu_generator(),
id = "my_menu")
})
observeEvent(input$my_menu, {
print("observer")
print(input$my_menu)
print(input$sidebarItemExpanded)
output$menu_output <- renderMenu({
sidebarMenu(menu_generator(),
id = "my_menu")
})
})
}
shinyApp(ui, server)
场景:展开图表2,然后单击“DDdashboard”。
在控制台:
[1] "observer"
[1] "DDdashboard"
[1] "Charts2"
[1] "menu_generator"
[1] "observer"
[1] "AAdashboard"
NULL
[1] "menu_generator"
“观察者” 之称的两倍(如后果 “menu_generator” 也),所以这造成意外行为。我的理解是,原因是renderMenu
。问题是 - 如何防止Shiny在这种情况下调用“观察者”两次?另请注意,在第二个电话input$my_menu
=“AAdashboard”。