- 问题描述：shiny在没有输入数据的数据下，也会生成空白图片，造成不美观。
library(shiny)
ui <- fluidPage(
fluidRow(
column(width=1),
column( textInput(inputId = "test1", label = "",
value = ""), width=2,style="background-color:lavender;border-radius: 10px")),
hr(),
fluidRow(
column(width=1),
column( textInput(inputId = "test2", label = "",
value = ""), width=2,style="background-color:lavender;border-radius: 10px")),
hr(),
actionButton("gobutton1","Start1"),
actionButton("gobutton2","Start2"),
fluidRow(
mainPanel(
plotOutput("distPlot1"))),
hr(),
fluidRow(
mainPanel(
plotOutput("distPlot2")))
)
server <- function(input,output){
data1 <- eventReactive(input$gobutton1,{
if(is.null(input$test1)){
return()
}
num <- input$test1
num <- as.numeric(num)
num1 <- num * 2;num2 <- num * 3;num3 <- num * 4;num4 <- num * 5;num5 <- num * 6
dt <- data.frame(id=paste0('id',1:5), number = c(num1, num2, num3, num4, num5))
dt
})
data2 <- eventReactive(input$gobutton2,{
if(is.null(input$test2)){
return()
}
num <- input$test2
num <- as.numeric(num)
num1 <- num / 2 ;num2 <- num / 3;num3 <- num / 4;num4 <- num / 5;num5 <- num / 6
dt <- data.frame(id=paste0('id',1:5), number = c(num1, num2, num3, num4, num5))
dt
})
output$distPlot1 <- renderPlot({
data <- data1()
library(ggplot2)
ggplot(data = data, mapping = aes(x = factor(id),
y = number, group = 1)) geom_point()
geom_line()
xlab('') ylab('Probility')
theme(axis.text.x = element_text(vjust = 0.5,
hjust = 0.5,
angle = 45))
})
output$distPlot2 <- renderPlot({
data <- data2()
library(ggplot2)
ggplot(data = data, mapping = aes(x = factor(id),
y = number, group = 1)) geom_point()
geom_line()
xlab('') ylab('Probility')
theme(axis.text.x = element_text(vjust = 0.5,
hjust = 0.5,
angle = 45))
})
}
shinyApp(ui=ui, server=server)
解决问题的关键是:
代码语言：javascript复制 data1 <- eventReactive(input$gobutton1,{
if(is.null(input$test1)){
return()
}
num <- input$test1
num <- as.numeric(num)
num1 <- num * 2;num2 <- num * 3;num3 <- num * 4;num4 <- num * 5;num5 <- num * 6
dt <- data.frame(id=paste0('id',1:5), number = c(num1, num2, num3, num4, num5))
dt
})该函数在默认不输入的情况下，会生成null，而导致后续的ggplot2不会生成空白图片，解决了我们的问题。
