R 为什么观察不会被无功值变化触发

代码在下面.

预期的行为如下:

1. 用户点击动作按钮run_analysis.
2. 这触发了input$run_analysis的observeEvent块，该块将无功值run_analysis_clicked更新为TRUE.
3. 该react 值的变化then应该触发执行observe块，这将更新mainPanelTabs选项卡集中的所选选项卡.

但事实并非如此.由于某些原因，observe块在改变run_analysis_clicked值后没有被触发.

我试着把这个和最低可重复性的样本配对.

library(shiny)

#### USER INTERFACE ####
ui <- fluidPage(
    titlePanel("Bootstrap Sample Size Simulator"),
    sidebarLayout(
        sidebarPanel(
            # Define the primary inputs needed to setup the sample size simulation
            fileInput("file_upload", "Upload a CSV file with sample data to use for sample size optimization:", accept = ".csv"),
            uiOutput("slider_output"),
            uiOutput("action_output")
        ),
        mainPanel(
            tabsetPanel(
                id = "mainPanelTabs",  # Add an ID for easier reference
                tabPanel("instructions", "Instructions content goes here."),
                tabPanel("data", "Data content goes here."),
                tabPanel("results", "Results content goes goes here.")
            )
        )
    )
)

#### SERVER ####
server <- function(input, output, session) {
    # Define reactive values that populate when the file is uploaded
    upload <- reactiveValues(
        isUploaded = FALSE, # flag signifying the file has been uploaded
        data = NULL, # empty placeholder for the data
        sample_max = NULL # initialize as empty
    )
    
    # Define reactive value that identifies when the run_analysis button has been clicked
    run_analysis_clicked <- reactive({
        FALSE # Flag is initially set to FALSE
    })
    
    # Define reactive value that updates the selected tab
    selectedTab <- reactiveVal("instructions")
    
    # Define function for creating the slider UI element for sample size limits selection
    slider_ui <- function() {
        if (upload$isUploaded) {
            sliderInput("sample_range",
                        label = "Range of Sample Sizes to simulate from the uploaded data:",
                        min = 2,
                        max = upload$sample_max,
                        step = 1,
                        value = c(2, upload$sample_max)
            )
        } else {
            NULL
        }
    }
    
    # Define function for creating the run analysis button
    action_ui <- function() {
        if (upload$isUploaded) {
            actionButton("run_analysis",
                         label = "Run the analysis"
            )
        } else {
            NULL
        }
    }
    
    # Update reactive values when file is uploaded
    observeEvent(input$file_upload, {
        upload$isUploaded <- TRUE  # update flag after file is uploaded
        upload$data <- read.csv(input$file_upload$datapath) # read the uploaded CSV file
        upload$sample_max <- nrow(upload$data) # update sample_max after file has been 
        print(paste("upload$sample_max:",upload$sample_max))
    })
    
    # Update reactive values when button is clicked
    observeEvent(input$run_analysis, {
                 run_analysis_clicked <- TRUE # update flag after button clicked
                 print(paste("run_analysis_clicked",run_analysis_clicked))
                 })
    
    # Update selected tab based on upload and button click events
    observe({
        print("observe triggered")
        print(paste("upload$isUploaded:",upload$isUploaded))
        print(paste("run_analysis_clicked:",run_analysis_clicked()))
        if (!upload$isUploaded) {
            selectedTab("instructions")
        } else if (run_analysis_clicked() == FALSE) {
            selectedTab("data")
        } else {
            selectedTab("results")
        }
        
        # Update the selected tab directly in the UI
        updateTabsetPanel(session, "mainPanelTabs", selected = selectedTab())
    })
    
    # Render the slider and action buttons conditionally upon file upload
    output$slider_output <- renderUI({
        slider_ui()
    })
    output$action_output <- renderUI({
        action_ui()
    })
}

#### APP ####
shinyApp(ui = ui, server = server)

下面是控制台输出(添加了解释触发输出的操作的注释):

Listening on http://xxxxxx
# App Initialized: 
[1] "observe triggered"
[1] "upload$isUploaded: FALSE"
[1] "run_analysis_clicked: FALSE"
# File Uploaded:
[1] "upload$sample_max: 15"
[1] "observe triggered"
[1] "upload$isUploaded: TRUE"
[1] "run_analysis_clicked: FALSE"
# Button Clicked:
[1] "run_analysis_clicked TRUE"

对于文件上传，我只是使用一个CSV文件，其中包含了我在Excel中创建的15个随机数字.它看起来是这样的: