在Shiny中渲染传单或情节时，删除不需要的空白

Question

我希望我的Shiny应用程序的用户能够通过单击事件面板中的单选按钮在两种类型的绘图之间进行选择。我写的代码很有效，但当从"；映射"；至"；绘图"；。有没有办法摆脱空白，把情节放在最上面？

# Load R packages
library(shiny)
library(shinythemes)
library(tidyverse)
library(leaflet)
set.seed(123)
year <- 2001:2020
event <- sample(1:100, size = 20, replace = TRUE)
dat <- as.data.frame(cbind(year, event))

# Define UI
ui <- fluidPage(
shinyjs::useShinyjs(),
theme = shinytheme("journal"),
navbarPage(
"Title",
tabPanel("About",
),
tabPanel("Events", 
fluidPage(
titlePanel("Title"),
sliderInput("range", label = "Move slider to select time period", min(2001), max(2020),
value = range(2001:2002), step = 1,  sep = "", width = "65%"),
sidebarLayout(
sidebarPanel(
radioButtons("plotType", "Plot type", choices = c("Map" = "m", "Chart" = "l"))),
mainPanel(
leafletOutput("map"),
plotOutput("plot"))
)
)
)
)
)

# Define server function  
server <- function(input, output, session) {

observeEvent(input$plotType, {
if(input$plotType == "l"){
shinyjs::disable("range")
}else{
shinyjs::enable("range")
}
})


output$plot <- renderPlot({
if (input$plotType == "l") {

ggplot(dat, aes(year, event)) +
geom_line() +
labs(x = "Year", y = "Events") +
theme_bw()
}
})  

output$map <- renderLeaflet({
if ( input$plotType == "m") {

leaflet(dat) %>% addTiles() %>%
fitBounds(~min(11), ~min(54), ~max(67), ~max(24))
}
})

} # server

# Create Shiny object
shinyApp(ui = ui, server = server)

Answer 1

因为map html对象仍然存在，但为空，所以空间很大。为了避免这种情况，我创建并观察了根据输入值隐藏或显示映射输出的Event。我对情节做了同样的事情，在cas中，你需要在它下面添加其他元素。

请注意，还有其他解决方案(例如conditionalPanel(，我只是给你一个我认为最简单的解决方案。

# Load R packages
library(shiny)
library(shinythemes)
library(tidyverse)
library(leaflet)
set.seed(123)
year <- 2001:2020
event <- sample(1:100, size = 20, replace = TRUE)
dat <- as.data.frame(cbind(year, event))

# Define UI
ui <- fluidPage(
shinyjs::useShinyjs(),
theme = shinytheme("journal"),
navbarPage(
"Title",
tabPanel("About",
),
tabPanel("Events", 
fluidPage(
titlePanel("Title"),
sliderInput("range", label = "Move slider to select time period", min(2001), max(2020),
value = range(2001:2002), step = 1,  sep = "", width = "65%"),
sidebarLayout(
sidebarPanel(
radioButtons("plotType", "Plot type", choices = c("Map" = "m", "Chart" = "l"))),
mainPanel(
leafletOutput("map"),
plotOutput("plot"))
)
)
)
)
)

# Define server function  
server <- function(input, output, session) {

# hide or show map and plot
observeEvent(input$plotType, {
if(input$plotType == "l"){
shinyjs::disable("range")
shinyjs::hide("map") 
shinyjs::show("plot")
} 
if(input$plotType == "m"){
shinyjs::enable("range")
shinyjs::show("map")
shinyjs::hide("plot")
} 
})

output$plot <- renderPlot({
req(input$plotType == "l") # good practice to use req instead of if
ggplot(dat, aes(year, event)) +
geom_line() +
labs(x = "Year", y = "Events") +
theme_bw()
})  

output$map <- renderLeaflet({
req(input$plotType == "m")
leaflet(dat) %>% addTiles() %>%
fitBounds(~min(11), ~min(54), ~max(67), ~max(24))
})


} # server

# Create Shiny object
shinyApp(ui = ui, server = server)