Shiny - plot with renderUI not display in shiny - r

Question

i just new in Shiny and i have a problem in shiny. i have a plot but the plot not display in shiny. and no message error.this is the code...
UI
library(shiny)
ui = fluidPage(
titlePanel("Hello Shiny!"),
sidebarLayout(
sidebarPanel(
),
mainPanel(
uiOutput("scatter")
))
)
server
library(shiny)
server = function(input, output) {
output$scatter <- renderUI({
datax <- matrix(c(1,2,3,4,5,6),6,1)
datay <- matrix(c(1,7,6,4,5,3),6,1)
titleplot<-"title"
summary <- "testing text"
pl <- plot(datax, datay, main = titleplot, xlab = "input$axis1", ylab = "input$axis2", pch=18, col="blue")
list(
pl,
summary
)
})
}

Answer 1

Actually you also can use uiOutput, and it is very useful sometimes, because you can create a user interface from the server side. This is the solution:
library(shiny)
ui = fluidPage(
titlePanel("Hello Shiny!"),
sidebarLayout(
sidebarPanel(
),
mainPanel(
uiOutput("scatter")
))
)
server = function(input, output) {
output$scatter <- renderUI({
datax <- matrix(c(1,2,3,4,5,6),6,1)
datay <- matrix(c(1,7,6,4,5,3),6,1)
titleplot<-"title"
summary <- "testing text"
output$plot_test <- renderPlot({
pl <- plot(datax, datay, main = titleplot, xlab = "input$axis1", ylab = "input$axis2", pch=18, col="blue")
})
plotOutput("plot_test")
})
}
# Run the application
shinyApp(ui = ui, server = server)

Answer 2

Change your renderUI function in server to renderPlot while uiOutput to plotOutput in ui correspondingly.
library(shiny)
ui = fluidPage(
titlePanel("Hello Shiny!"),
sidebarLayout(
sidebarPanel(
),
mainPanel(
plotOutput("scatter")
))
)
server = function(input, output) {
output$scatter <- renderPlot({
datax <- matrix(c(1,2,3,4,5,6),6,1)
datay <- matrix(c(1,7,6,4,5,3),6,1)
titleplot<-"title"
summary <- "testing text"
pl <- plot(datax, datay, main = titleplot, xlab = "input$axis1", ylab = "input$axis2", pch=18, col="blue")
list(
pl,
summary
)
})
}
shinyApp(ui, server)

Answer 3

You need to assign seperate output slots for the plot and the text. That is because shiny uses different (css) classes for each of tose render functions. The following code should do what you want.
library(shiny)
ui <- fluidPage(
titlePanel("Hello Shiny!"),
sidebarLayout(
sidebarPanel(),
mainPanel(
plotOutput("scatter"),
textOutput("testingText")
)
)
)
server <- function(input, output) {
output$scatter <- renderPlot({
datax <- matrix(c(1, 2, 3, 4, 5, 6), 6, 1)
datay <- matrix(c(1, 7, 6, 4, 5, 3), 6, 1)
titleplot <- "title"
plot(datax, datay, main = titleplot, xlab = "input$axis1",
ylab = "input$axis2", pch = 18, col = "blue")
})
output$testingText <- renderText({
"testing text"
})
}
shinyApp(ui, server)
Additional note: The line
pl <- plot( ... )
does not make sense. In R, plots can not be saved as objects. ggplots are an exception, but you would still have to use renderPlot to display a ggplot object in shiny.