无法删除以前插入的 UI

Question

在下面的应用程序中，我无法删除之前插入的 UI。不知道为什么。任何人都可以帮忙.................................................................. ....................

---
title: "Untitled"
runtime: shiny
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
---

```{r setup, include=FALSE}
library(flexdashboard)
library(rhandsontable)
```r

Column {data-width=650}
-----------------------------------------------------------------------

### Insert and Remove UI

```{r}

actionButton("add", "Add UI")
actionButton("rmv", "Remove UI")
 observeEvent(input$add, {
    insertUI(
      selector = "#add",
      where = "afterEnd",
      ui = textInput(paste0("txt", input$add),
                     "Insert some text"),multiple = FALSE
    )
  })
 observeEvent(input$rmv, {
    removeUI(
      selector = "div:has(< #txt)"
    )
  })
```

```

Answer 1

我们可以使用seq_len(input$add) 获取之前的id，其中input$add 是1,2,3,...等，然后使用paste0 和sprintf 构造一个jQuery 语句

---
title: "Untitled"
runtime: shiny
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
---

```{r setup, include=FALSE}
library(flexdashboard)
library(rhandsontable)
```

Column {data-width=650}
-----------------------------------------------------------------------

```{r}



  ### Insert and Remove UI

actionButton("add", "Add UI")
actionButton("rmv", "Remove UI")
observeEvent(input$add, {
    insertUI(
      selector = "#add",
      where = "afterEnd",
      ui = textInput(paste0("txt", input$add),
                     sprintf("Insert some text for %i",input$add)),multiple = FALSE
    )
  })
observeEvent(input$rmv, {
    removeUI(
      #Remove the last UI
      #selector = sprintf("div:has(> #txt%i)",input$add),
      #Remove all previous UIs
      selector = sprintf("div:has(%s)",paste0('> #txt', seq_len(input$add), collapse = ",")),
      immediate = TRUE,
      multiple = TRUE
    )
  })
```

更新

每次用户点击时删除最后一个用户界面删除用户界面

### Insert and Remove UI

actionButton("add", "Add UI")
actionButton("rmv", "Remove UI")
data = reactiveValues(tmp=0)
observeEvent(input$add, {
    data$tmp <- c(data$tmp,input$add)

    insertUI(
      selector = "#add",
      where = "afterEnd",
      ui = textInput(paste0("txt", input$add),
                     sprintf("Insert some text for %i",input$add)),multiple = FALSE
    )
  })

observeEvent(input$rmv, {
    rm <- tail(data$tmp, 1)
    data$tmp <- setdiff(data$tmp, rm)

    removeUI(
      #Remove the last UI
      #selector = sprintf("div:has(> #txt%i)",input$add),
      #Remove all previous UIs
      selector = sprintf("div:has(%s)",paste0('> #txt', rm, collapse = ",")),
      immediate = TRUE,
      multiple = TRUE
    )
  })