r - 根据输入值显示/隐藏 shinyTree 节点并维护树状态

Question

我想根据用户提供的输入值过滤闪亮树中的节点。我有一个初步尝试，但问题是树在输入后不保持状态，例如打开/关闭节点或选定节点。例如，在下面的示例代码中，假设我扩展了 1-3a 和 4-6，并选择了值 3 和 5。

如果我将滑块移动到 2，这应该从 1-3a 和 1-3b 中删除 1 条目，我想保持 1-3a 和 4-6 展开，并检查值 3-6。但是，我每次都从头开始创建树，所以所有状态都丢失了。

有没有办法在闪亮的树中显示/隐藏节点以保持状态？

library(shiny)
library(shinyTree)
library(dplyr)

dat <- tibble(
  grp=rep(c("1-3a","1-3b","4-6"),each=3),
  leaf=c(1:3,1:3,4:6),
  val=c(1:3,1:3,4:6),
)

#' Recursively walks down the columns of a dataframe making nested groups
listTree <- function(dat) {
  if(ncol(dat) > 2) {
    x <- dat %>% nest(data=-1)
    lst <- as.list(x[[2]])
    names(lst) <- x[[1]]
    lst %>% map(listTree)
  } else if(ncol(dat)==2) {
    lst<-as.list(dat[[2]])
    names(lst)<-dat[[1]]
    return(lst)
  } else if(ncol<2) {
    stop('ERROR')
  }
}

ui <- fluidPage(
  p('Filter nodes < selected value'),
  sliderInput("num", "Value",
              min = 1, max = 6, value = 1),
  shinyTree("tree",checkbox=TRUE)
)
server <- function(input, output, session) {
  

  datr <- reactive({
    dat %>% filter(val >= input$num)
  })
  
  output$tree <- renderTree({listTree(datr())})
  
}

shinyApp(ui, server)

Answer 1

'jsTreeR' 包类似于'shinyTree' 包，但它允许更多可能性。这是实现您想要的目标的方法：

library(jsTreeR)
library(shiny)
library(htmlwidgets)
library(magrittr)

onrender <- c(
  "function(el, x) {",
  "  Shiny.addCustomMessageHandler('hideNodes', function(threshold) {",
  "    var tree = $.jstree.reference(el.id);",
  "    var json = tree.get_json(null, {flat: true});",
  "    for(var i = 0; i < json.length; i++) {",
  "      if(tree.is_leaf(json[i].id) && json[i].text <= threshold) {",
  "        tree.hide_node(json[i].id);",
  "      } else {",
  "        tree.show_node(json[i].id);",
  "      }",
  "    }",
  "  });",
  "}"
)

nodes <- list(
  list(
    text = "1-3a",
    children = list(
      list(
        text = "1"
      ),
      list(
        text = "2"
      ),
      list(
        text = "3"
      )
    )
  ),
  list(
    text = "1-3b",
    children = list(
      list(
        text = "1"
      ),
      list(
        text = "2"
      ),
      list(
        text = "3"
      )
    )
  ),
  list(
    text = "4-6",
    children = list(
      list(
        text = "4"
      ),
      list(
        text = "5"
      ),
      list(
        text = "6"
      )
    )
  )
)

ui <- fluidPage(
  br(),
  fluidRow(
    column(
      3,
      jstreeOutput("tree")
    ),
    column(
      9,
      sliderInput(
        "threshold",
        label = "Threshold",
        min = 0, max = 10, value = 0, step = 1
      )
    )
  )
)

server <- function(input, output, session){

  output[["tree"]] <- renderJstree({
    jstree(nodes, checkboxes = TRUE) %>% onRender(onrender)
  })

  observeEvent(input[["threshold"]], {
    session$sendCustomMessage("hideNodes", input[["threshold"]])
  })

}

shinyApp(ui, server)