我有一个闪亮的应用程序，里面有一个漂亮的幻灯片和与每张照片相关联的输入。用户会输入他们的名字，然后猜测照片中每个人的年龄。每次用户用箭头推进幻灯片，输入也会推进。用户必须填写输入，应用程序的其余部分才能工作（应用程序的其余部分在这里没有显示）。我想要的是，每次点击箭头时，应用程序都会检查相关的输入是否为空，如果是，幻灯片将不会前进，并会弹出一条小消息。我试过用shinyjs、shinyvalidate和shinyalert来解决这个问题，但是我没有找到一个解决方案。

library(shiny)
library(shinyalert)
library(slickR)
library(tidyverse)
library(shinyvalidate)
library(shinyjs)

js <- "
$(document).ready(function(){
  var ss = document.getElementById('slickr');
  
  // create an observer instance
  var observer = new MutationObserver(function(mutations) {
    var index = $(ss).find('.slick-current').data('slick-index');
    Shiny.setInputValue('imageIndex', parseInt(index)+1);
  });
  // configuration of the observer
  var config = {subtree: true, attributes: true};
  // observe
  observer.observe(ss, config);
 
  var deleteThis = function(elem){
        elem.style.display = 'none';
        // elem.style.visibility = 'hidden';
};

})
"

slider <- "$('.slider').slick({
  autoplay: false,
  dots: true,
  customPaging : function(slider, i) {
    var thumb = $(slider.$slides[i]).data();
    
    return '<a>'+1:6[i]+'</a>';
  },
  responsive: [{ 
    breakpoint: 500,
    settings: {
      dots: false,
      arrows: false,
      infinite: false,
      slidesToShow: 2,
      slidesToScroll: 2
    } 
  }]
});"

cP1=htmlwidgets::JS("function(slick,index) {return '<a>'+(index+1)+'</a>';}")

imgs <- list.files("samplepictures/", pattern=".jpg|.jpeg|.png", full.names = TRUE)
imgs <- imgs[!grepl("photo_ages",imgs)]

photoages <- lapply(1:6,function(x){ numericInput(paste0("Photo",x),
                                                  paste0("Photo ",x," Age Guess:"),
                                                  min = 1,
                                                  max = 100,
                                                  value = NULL)})

texfn <- function(x= "Guesser"){
  textInput("Name",paste(x))
}
actionfn <- function(){
  actionButton("go", "Submit All Guesses")
}

photoages <- as.vector(photoages)

photoages <- c(list(texfn()),
               photoages,
               list(actionfn()))

ui <- fluidPage(
  useShinyjs(),
  
  titlePanel("Photo Guesses"),
  mainPanel(

    tags$head(
      tags$script(HTML(js))
    ),
    tags$head(
      tags$style(HTML("
    .arrows {
      height: 30px;
    }
    .slick-prev {
      left: 10px; # moves right
    }
    .slick-next {
      left: 30px;  # moves right
    }
    "))),
    
    fluidRow(
      column(12),
      column(4,align = "left",tags$body( div(id = "mydiv",uiOutput("photoinput"))) ) ,
      column(4, align = "left",div(id = "npht",h4("Advance:")), tags$br(), tags$div(id = "arr",class="arrows"))
    ),

    tags$hr(),
    slickROutput("slickr") ,
    tags$br()
    
  )
)

server <- function(input, output,session) {
 
  iv <- InputValidator$new()
  iv$add_rule("Name", sv_required())
  iv$add_rule("Photo1", sv_between(1,100, allow_na = T))
  iv$add_rule("Photo2", sv_between(1,100, allow_na = T))
  iv$add_rule("Photo3", sv_between(1,100, allow_na = T))
  iv$add_rule("Photo4", sv_between(1,100, allow_na = T))
  iv$add_rule("Photo5", sv_between(1,100, allow_na = T))
  iv$add_rule("Photo6", sv_between(1,100, allow_na = T))
  iv$enable()
  
  
  observeEvent(input[["imageIndex"]],{
    values <- reactiveValues()
    
    values$click <- input[["imageIndex"]]
    if(input[["imageIndex"]] >7){
      removeUI("#npht")
      removeUI("#arr")
    }
    
  })
  

  output$slickr <- renderSlickR({
    
    
    imgs <- list.files("samplepictures/", pattern=".jpg|.jpeg|.png", full.names = TRUE)
    imgs <- imgs[!grepl("photo_ages",imgs)]
    (slickR(imgs) +
        
        slickR::settings(dots = TRUE,
                         #customPaging = cP1,
                         appendArrows = '.arrows',
                         prevArrow = "null"
        )) 
  })
  
  output[["photoinput"]] <- renderUI({photoages[input[["imageIndex"]]]})
     
}

# Run the application
shinyApp(ui = ui, server = server)