在 R Shiny 中，为什么一个 observeEvent() 会使另一个 observeEvent() 无效？

Question

在运行以下代码时，observeEvent(input$matrix2, {...}) 使observeEvent(input$matrix1, {...}) 无效。为什么会发生这种情况，我该如何解决？

矩阵 1 和矩阵 2 是相连的。从矩阵 1 下游到矩阵 2 的值作为矩阵 2“场景 1”，矩阵 2 允许用户通过水平扩展矩阵输入其他场景。单击单个操作按钮后，矩阵 2 在模式对话框中呈现。当首先输入矩阵 1 时，应用程序（绘图）工作正常（将用户输入绘制到矩阵 1 和 2 中）；但是当矩阵 2 在输入到矩阵 1 之前被查看（我们没有任何用户输入到矩阵 2 中），那么矩阵 1 就变得无用了。无用是指不再绘制矩阵 1 的输入。

用于说明目的的输出只是矩阵输入的总和，绘制在 10 个周期内，每个 sumMat(...) 函数。

我玩过isolate(...)、req(...) 等的所有变体，但到目前为止都没有运气。

底部的图片说明了问题：前 2 张图片显示 App 在先输入矩阵 1 时运行良好；第三张图片显示在矩阵 1 之前访问矩阵 2 时失败。

library(dplyr)
library(ggplot2)
library(shiny)
library(shinyMatrix)

sumMat <- function(x){return(rep(sum(x,na.rm = TRUE), 10))}

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      matrixInput("matrix1",
                  value = matrix(c(60,5), ncol = 2, dimnames = list(NULL,c("X","Y"))),
                  rows = list(extend = TRUE, delete = TRUE), class = "numeric"),
      actionButton("matrix2show","Add scenarios"),
      ),
    mainPanel(plotOutput("plot"))  
  )    
)

server <- function(input, output, session){
  
  observeEvent(input$matrix1, {
    tmpMat1 <- input$matrix1
    if(any(rownames(input$matrix1) == "")){rownames(tmpMat1) <- paste("Row", seq_len(nrow(input$matrix1)))}
    updateMatrixInput(session, inputId = "matrix1", value = tmpMat1)
  })
  
  observeEvent(input$matrix2, { ### updates matrix 2 to reflect larger of matrix 1 and matrix 2 rows
    req(input$matrix1)
    a <- apply(input$matrix2,2,'length<-',max(nrow(input$matrix2),nrow(input$matrix1)))
    b <- apply(input$matrix1,2,'length<-',max(nrow(input$matrix2),nrow(input$matrix1)))
    c <- if(length(a) == 2){c(b)} else {c(b,a[,-1:-2])}
    d <- ncol(input$matrix2)
    
    tmpMat2 <- matrix(c(c), ncol = d)
    tmpMat2[1,2] <- input$matrix1[1,2] 
    colnames(tmpMat2) <- paste("Scenario",rep(1:ncol(tmpMat2),each=2,length.out=ncol(tmpMat2)))
    rownames(tmpMat2) <- paste("Row", seq_len(nrow(input$matrix2)))
    
    updateMatrixInput(session,inputId="matrix2",value=tmpMat2)
  })
  
  observeEvent(input$matrix2show,{
    showModal(
      modalDialog(
        matrixInput("matrix2",
                    label = "Matrix 2 (Value Y applied in Period X):",
                    value = if(is.null(input$matrix2))
                    {matrix(c(input$matrix1[,1],input$matrix1[,2]), 
                            ncol = 2, dimnames = list(NULL, rep("Scenario 1", 2)))}
                    else {input$matrix2},
                    rows = list(extend = TRUE, delete = TRUE),
                    cols = list(extend = TRUE, delta = 2, delete = TRUE, multiheader = TRUE),
                    class = "numeric"),
      footer = tagList(modalButton("Exit box"))
      ))
  })
  
  plotData <- reactive({
    tryCatch(
      if(isTruthy(input$matrix2)){
        lapply(seq_len(ncol(input$matrix2)/2), # column counter to set matrix index as it expands
               function(i){
                 tibble(Scenario = colnames(input$matrix2)[i*2-1],
                   X = seq_len(10),Y = sumMat(input$matrix2[,(i*2-1):(i*2), drop = FALSE]))
               }) %>% bind_rows()
        }
      else {tibble(Scenario = "Scenario 1", X = seq_len(10),Y = sumMat(input$matrix1))},
      error = function(e) NULL)
  })
  
  output$plot <- renderPlot({
    req(plotData())
    plotData() %>% ggplot() + geom_line(aes(x = X, y = Y, colour = as.factor(Scenario)))
  })
}

shinyApp(ui, server)

Answer 1

这是部分解决方案。每次单击 actionButton 时，都会为 matrix2 创建相同的 ID。这是一个问题，因为 Shiny 需要唯一的 ID。一旦我们对此进行调整，它就可以正常工作。见下文。您仍然需要研究如何显示 input$matrix2 的先前列。

library(dplyr)
library(ggplot2)
library(shiny)
library(shinyMatrix)

sumMat <- function(x){return(rep(sum(x,na.rm = TRUE), 10))}

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      matrixInput("matrix1",
                  value = matrix(c(60,5), ncol = 2, dimnames = list(NULL,c("X","Y"))),
                  rows = list(extend = TRUE, delete = TRUE), class = "numeric"),
      actionButton("matrix2show","Add scenarios"),
    ),
    mainPanel(plotOutput("plot"))  
  )    
)

server <- function(input, output, session){
  rv <- reactiveValues(tmpMat=NULL)
  observeEvent(input$matrix1, {
    tmpMat1 <- input$matrix1
    if(any(rownames(input$matrix1) == "")){rownames(tmpMat1) <- paste("Row", seq_len(nrow(input$matrix1)))}
    updateMatrixInput(session, inputId = "matrix1", value = tmpMat1)
  })
  
  
  observeEvent(input$matrix2, { ### updates matrix 2 to reflect larger of matrix 1 and matrix 2 rows
    req(input[[paste0("matrix2",input$matrix2show)]])
    req(input$matrix1)
    imatrix2 <- input[[paste0("matrix2",input$matrix2show)]]
    a <- apply(imatrix2,2,'length<-',max(nrow(imatrix2),nrow(input$matrix1)))
    b <- apply(input$matrix1,2,'length<-',max(nrow(imatrix2),nrow(input$matrix1)))
    c <- if(length(a) == 2){c(b)} else {c(b,a[,-1:-2])}
    d <- ncol(imatrix2)
    
    tmpMat2 <- matrix(c(c), ncol = d)
    tmpMat2[1,2] <- input$matrix1[1,2] 
    colnames(tmpMat2) <- paste("Scenario",rep(1:ncol(tmpMat2),each=2,length.out=ncol(tmpMat2)))
    rownames(tmpMat2) <- paste("Row", seq_len(nrow(imatrix2)))
    
    updateMatrixInput(session,inputId=paste0("matrix2",input$matrix2show),value=tmpMat2)
    rv$tmpMat <- tmpMat2
  })
  observe({print(rv$tmpMat)})
  observeEvent(input$matrix2show,{
    if (input$matrix2show==1) ivalue <- matrix(c(input$matrix1[,1],input$matrix1[,2]), 
                                               ncol = 2, dimnames = list(NULL, rep("Scenario 1", 2)))
    else{ if (!is.null(rv$tmpMat)) ivalue <- rv$tmpMat else ivalue <- input$matrix1}
    showModal(
      modalDialog(
        matrixInput(paste0("matrix2",input$matrix2show),
                    label = "Matrix 2 (Value Y applied in Period X):",
                    value = ivalue,
                    rows = list(extend = TRUE, delete = TRUE),
                    cols = list(extend = TRUE, delta = 2, delete = TRUE, multiheader = TRUE),
                    class = "numeric"),
        footer = tagList(modalButton("Exit box"))
      ))
  })
  
  plotData <- reactive({
    req(input$matrix1)
    imatrix2 <- input[[paste0("matrix2",input$matrix2show)]]
    tryCatch(
      if(isTruthy(imatrix2)){
        lapply(seq_len(ncol(imatrix2)/2), # column counter to set matrix index as it expands
               function(i){
                 tibble(Scenario = colnames(imatrix2)[i*2-1],
                        X = seq_len(10),Y = sumMat(imatrix2[,(i*2-1):(i*2), drop = FALSE]))
               }) %>% bind_rows()
      }
      else {tibble(Scenario = "Scenario 1", X = seq_len(10),Y = sumMat(input$matrix1))},
      error = function(e) NULL)
  })
  
  output$plot <- renderPlot({
    req(plotData())
    plotData() %>% ggplot() + geom_line(aes(x = X, y = Y, colour = as.factor(Scenario)))
  })
}

shinyApp(ui, server)