问题
Im creating a shiny app that queries an SQL database. I want to warn the user if the queried data has entries on two dates. Moreover, I want the user to be able to select which set of data to query. Here is an example:
Server
# Create example data
set.seed(10)
MeasurementA <- rnorm(1000, 5, 2)
MeasurementB <- rnorm(1000, 5, 2)
Wafer <- rep(c(1:100), each=10)
ID <- rep(c(101:200), each=10)
Batch <- rep(LETTERS[seq(from=1, to =10)], each=100)
Date <- rep(seq(as.Date("2001-01-01"), length.out = 100, by="1 day"), each=10)
# Add data for Wafer 1 with a new date
W2 <- rep(1, each=10)
ID2 <- rep(101, each=10)
Batch2 <- rep("A", each=10)
Date2 <- rep(as.Date("2001-04-11"), each=10)
MA2 <- rnorm(10, 5, 2)
MB2 <- rnorm(10, 5, 2)
df <- data.frame(Batch, Wafer, ID, MeasurementA, MeasurementB, Date)
ee <- data.frame(Batch2, W2, ID2, MA2, MB2, Date2)
colnames(ee) <- c("Batch", "Wafer", "ID", "MeasurementA", "MeasurementB", "Date")
# Data frame now how two sets of date for Wafer 1 on different dates
dd <- rbind(df, ee)
dd$Date <- factor(dd$Date)
# Create local connection (in reality this will be a connection to a host site)
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTable(con, "dd", dd)
query <- function(...) dbGetQuery(con, ...)
# Create empty data frames to populate
wq = data.frame()
sq = data.frame()
shinyServer(function(input, output){
# create data frame to store reactive data set from query
values <- reactiveValues()
values$df <- data.frame()
# Action button for first query
d <- eventReactive(input$do, { input$wafer })
# First stage of reactive query
a <- reactive({ paste("Select ID from dd where Wafer=",d(), sep="") })
wq <- reactive({ query( a() ) })
# Output to confirm query is correct
output$que <- renderPrint({ a() })
output$pos <- renderPrint( wq()[1,1] )
# Action button to add results from query to a data frame
e <- eventReactive(input$do2, { wq()[1,1] })
b <- reactive({ paste("select cast(Wafer as varchar) as Wafer, cast(Batch as varchar) as Batch, MeasurementA, MeasurementB, Date from dd where ID=",e()," Order by ID asc ;", sep="") })
# observe e() so that data is not added until user presses action button
observe({
if (!is.null(e())) {
sq <- reactive({ query( b() ) })
# add query to reactive data frame
values$df <- rbind(isolate(values$df), sq())
}
})
asub <- eventReactive(input$do3,{subset(values$df, MeasurementA > input$Von[1] & MeasurementA < input$Von[2] )})
observeEvent(input$do4, {
values$df <- NULL
})
output$boxV <- renderPlot({
ggplot(asub(), aes_string('Wafer', input$char, fill='Batch')) + geom_boxplot()
})
})
UI
shinyUI(fluidPage(
titlePanel("Generic grapher"),
sidebarLayout(
sidebarPanel(
numericInput("wafer", label = h3("Input wafer ID:"), value = NULL),
actionButton("do", "Search wafer"),
actionButton("do2", "Add to data frame"),
actionButton("do3", "Show"),
actionButton("do4", "Clear"),
selectInput("char", label="Boxplot choice:",
choices = list("A"="MeasurementA", "B"="MeasurementB"),
selected="Von.fwd"),
sliderInput("Von", label = "A range:",
min=0, max=10, value=c(0,10), step=0.1)
),
mainPanel(
verbatimTextOutput("que"),
verbatimTextOutput("pos"),
plotOutput("boxV")
#dataTableOutput(outputId="posi")
)
)
)
)
In the above, if you search for wafer "1" it plots all the data even though there are two dates for wafer 1 (this is expected). So I was thinking that if when I click "Search wafer" I could get a popup if two dates existed for that wafer. So far I have read this:
Add a popup with error, warning to shiny
and this:
Create a pop-up menu with right click about an object
Which shows I can produce a warning message (although I havent tried doing this yet). But I wonder if there is some way to make the popup interactive so as to select the desired date. Perhaps I should contact the creator of shinyBS, that looks like my best option?
回答1:
Maybe you could use a conditionalPanel for that: http://shiny.rstudio.com/reference/shiny/latest/conditionalPanel.html
回答2:
I created a sample App which should give you a good introduction on how you can use Alerts. I'm not using the alerts from shinyBS package as you can see, but instead I used session$sendCustomMessage to send a message with JS alert functionality. I've added some comments in the code so have a look. Note that I make use of the sub function to create the desired text by substituting my expression into the SOMETHING part of the string.
rm(list = ls())
library(shiny)
library(DT)
ui <- fluidPage(
# Inlcude the line below in ui.R so you can send messages
tags$head(tags$script(HTML('Shiny.addCustomMessageHandler("jsCode",function(message) {eval(message.value);});'))),
titlePanel("Pop-up Alerts"),
sidebarPanel(
sliderInput("my_slider", "Range Slider:", min = 0, max = 150, value = 40, step=1),
dateInput('my_daterange',label = '',value = Sys.Date()),
actionButton("run","Execute")),
mainPanel(DT::dataTableOutput('tbl'))
)
server <- function(input, output, session) {
# Alert below will trigger if the slider is over 100
observe({
if(input$my_slider >= 100)
{
my_slider_check_test <- "Your slider value is above 100 - no data will be displayed"
js_string <- 'alert("SOMETHING");'
js_string <- sub("SOMETHING",my_slider_check_test,js_string)
session$sendCustomMessage(type='jsCode', list(value = js_string))
}
})
# Alert below about dates will notify you if you selected today
observe({
if (is.null(input$run) || input$run == 0){return()}
isolate({
input$run
if(input$my_daterange == Sys.Date())
{
my_date_check_test <- "Today Selected"
js_string <- 'alert("SOMETHING");'
js_string <- sub("SOMETHING",my_date_check_test,js_string)
session$sendCustomMessage(type='jsCode', list(value = js_string))
}
# Alert will also trigger and will notify about the dates
if(input$my_daterange == Sys.Date())
{
my_date_check_test <- paste0("You selected: ",input$my_daterange)
js_string <- 'alert("SOMETHING");'
js_string <- sub("SOMETHING",my_date_check_test,js_string)
session$sendCustomMessage(type='jsCode', list(value = js_string))
}
})
})
my_data <- reactive({
if(input$run==0){return()}
isolate({
input$run
if(input$my_slider >= 100)
{
# Alert below will trigger if you adjusted the date but slider is still 100
my_slider_check_test <- "Slider is still over 100"
js_string <- 'alert("SOMETHING");'
js_string <- sub("SOMETHING",my_slider_check_test,js_string)
session$sendCustomMessage(type='jsCode', list(value = js_string))
}
if(input$my_slider < 100)
{
iris[1:input$my_slider,]
}
})
})
output$tbl = DT::renderDataTable(my_data(), options = list(lengthChange = FALSE))
}
shinyApp(ui = ui, server = server)
The output below of some pop-ups is in IE, Google Chrome will be different:
#1 Slider over 100 alert
#2 Dates: Today Selected
#3 Dates: Simply alerting by printing the date
#4 Alert to show that the slider is still over 100
#5 If the slider is under 100, you get tableoutput
来源：https://stackoverflow.com/questions/32226331/r-shiny-pop-up-window-with-options