Package 'shinyfocus'

Respond when input loses focus

Description

Set up a shiny::observeEvent() observer to trigger when the named input loses focus.

Usage

on_blur(
  id,
  handler_expr,
  ...,
  priority = 99999,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

id	The ID string of an input.
handler_expr	The expression to trigger whenever the specified input loses focus. This expression is quoted and executed in the calling environment.
...	Arguments passed on to shiny::observeEvent label A label for the observer or reactive, useful for debugging. suspended If TRUE, start the observer in a suspended state. If FALSE (the default), start in a non-suspended state. autoDestroy If TRUE (the default), the observer will be automatically destroyed when its domain (if any) ends. ignoreNULL Whether the action should be triggered (or value calculated, in the case of eventReactive) when the input event expression is NULL. See Details. once Whether this observeEvent should be immediately destroyed after the first time that the code in handlerExpr is run. This pattern is useful when you want to subscribe to a event that should only happen once.
priority	An integer that controls the priority with which the observer should be executed. It often makes sense for this priority to be very high to avoid conflicts.
session	The session (aka domain) in which the observer will be created and executed. The default is almost always desired.

Value

A shiny observer (see shiny::observe()).

See Also

Other observers: on_focus_change(), on_focus()

Examples

## Only run examples in interactive R sessions
if (interactive()) {
  # App 1: A relatively simple ui without modules.
  shiny::shinyApp(
    ui = shiny::fluidPage(
      shinyfocus_js_dependency(),
      shiny::textInput("input1", "Input 1"),
      shiny::textInput("input2", "Input 2"),
      shiny::actionButton("go_button", "Go!"),
      shiny::textOutput("blurring")
    ),
    server = function(input, output, session) {
      # Update the value in blurring whenever input1 loses focus.
      on_blur(
        "input1",
        output$blurring <- shiny::renderText(
          paste(
            "You left input1 at",
            Sys.time()
          )
        )
      )
    }
  )

  # App 2: With module.
  blurUI <- function(id) {
    shiny::tagList(
      shiny::textInput(shiny::NS(id, "observe_me"), "Observe me"),
      shiny::textOutput(NS(id, "blurring"))
    )
  }
  blurServer <- function(id) {
    shiny::moduleServer(id, function(input, output, session) {
      on_blur(
        "observe_me",
        output$blurring <- shiny::renderText(
          paste(
            "You left observe_me at",
            Sys.time()
          )
        )
      )
    })
  }

  shiny::shinyApp(
    ui = shiny::fluidPage(
      shinyfocus_js_dependency(),
      blurUI("blur_module"),
      shiny::textInput("another_input", "Another input"),
      shiny::actionButton("go_button", "Go!")
    ),
    server = function(input, output, session) {
      blurServer("blur_module")
    }
  )
}

---

Respond when input gains focus

Description

Set up a shiny::observeEvent() observer to trigger when the named input gains focus.

Usage

on_focus(
  id,
  handler_expr,
  ...,
  priority = 99999,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

id	The ID string of an input.
handler_expr	The expression to trigger whenever the specified input gains focus. This expression is quoted and executed in the calling environment.
...	Arguments passed on to shiny::observeEvent label A label for the observer or reactive, useful for debugging. suspended If TRUE, start the observer in a suspended state. If FALSE (the default), start in a non-suspended state. autoDestroy If TRUE (the default), the observer will be automatically destroyed when its domain (if any) ends. ignoreNULL Whether the action should be triggered (or value calculated, in the case of eventReactive) when the input event expression is NULL. See Details. once Whether this observeEvent should be immediately destroyed after the first time that the code in handlerExpr is run. This pattern is useful when you want to subscribe to a event that should only happen once.
priority	An integer that controls the priority with which the observer should be executed. It often makes sense for this priority to be very high to avoid conflicts.
session	The session (aka domain) in which the observer will be created and executed. The default is almost always desired.

Value

A shiny observer (see shiny::observe()).

See Also

Other observers: on_blur(), on_focus_change()

Examples

## Only run examples in interactive R sessions
if (interactive()) {
  # App 1: A relatively simple ui without modules.
  shiny::shinyApp(
    ui = shiny::fluidPage(
      shinyfocus_js_dependency(),
      shiny::textInput("input1", "Input 1"),
      shiny::textInput("input2", "Input 2"),
      shiny::actionButton("go_button", "Go!"),
      shiny::textOutput("focusing")
    ),
    server = function(input, output, session) {
      # Update the value in focusing whenever input1 has focus.
      on_focus(
        "input1",
        output$focusing <- shiny::renderText(
          paste(
            "You entered input1 at",
            Sys.time()
          )
        )
      )
    }
  )

  # App 2: With module.
  focusUI <- function(id) {
    shiny::tagList(
      shiny::textInput(shiny::NS(id, "observe_me"), "Observe me"),
      shiny::textOutput(NS(id, "focusing"))
    )
  }
  focusServer <- function(id) {
    shiny::moduleServer(id, function(input, output, session) {
      on_focus(
        "observe_me",
        output$focusing <- shiny::renderText(
          paste(
            "You entered observe_me at",
            Sys.time()
          )
        )
      )
    })
  }

  shiny::shinyApp(
    ui = shiny::fluidPage(
      shinyfocus_js_dependency(),
      focusUI("focus_module"),
      shiny::textInput("another_input", "Another input"),
      shiny::actionButton("go_button", "Go!")
    ),
    server = function(input, output, session) {
      focusServer("focus_module")
    }
  )
}

---

Respond when input changes focus

Description

Set up a shiny::observeEvent() observer to trigger when the named input gains or loses focus.

Usage

on_focus_change(
  id,
  handler_expr,
  ...,
  change_on = c("focus", "blur"),
  priority = 99999,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

id	The ID string of an input.
handler_expr	The expression to trigger whenever the specified input changes focus. This expression is quoted and executed in the calling environment.
...	Arguments passed on to shiny::observeEvent label A label for the observer or reactive, useful for debugging. suspended If TRUE, start the observer in a suspended state. If FALSE (the default), start in a non-suspended state. autoDestroy If TRUE (the default), the observer will be automatically destroyed when its domain (if any) ends. ignoreNULL Whether the action should be triggered (or value calculated, in the case of eventReactive) when the input event expression is NULL. See Details. once Whether this observeEvent should be immediately destroyed after the first time that the code in handlerExpr is run. This pattern is useful when you want to subscribe to a event that should only happen once.
change_on	A character indicating whether the observer should update when the input becomes focused and/or when the input becomes blurred.
priority	An integer that controls the priority with which the observer should be executed. It often makes sense for this priority to be very high to avoid conflicts.
session	The session (aka domain) in which the observer will be created and executed. The default is almost always desired.

Value

A shiny observer (see shiny::observe()).

See Also

Other observers: on_blur(), on_focus()

Examples

if (interactive()) {
  # App 1: A relatively simple ui without modules.
  shiny::shinyApp(
    ui = shiny::fluidPage(
      shinyfocus_js_dependency(),
      shiny::textInput("input1", "Input 1"),
      shiny::textInput("input2", "Input 2"),
      shiny::actionButton("go_button", "Go!"),
      shiny::textOutput("changing")
    ),
    server = function(input, output, session) {
      # Update the value in "changing" whenever input1 gains or loses focus.
      on_focus_change(
        "input1",
        output$changing <- shiny::renderText(
          paste(
            "You entered or left input1 at",
            Sys.time()
          )
        )
      )
    }
  )

  # App 2: With module.
  changeUI <- function(id) {
    shiny::tagList(
      shiny::textInput(shiny::NS(id, "observe_me"), "Observe me"),
      shiny::textOutput(NS(id, "changing"))
    )
  }
  changeServer <- function(id) {
    shiny::moduleServer(id, function(input, output, session) {
      on_focus_change(
        "observe_me",
        output$changing <- shiny::renderText(
          paste(
            "You entered or left observe_me at",
            Sys.time()
          )
        )
      )
    })
  }

  shiny::shinyApp(
    ui = shiny::fluidPage(
      shinyfocus_js_dependency(),
      changeUI("change_module"),
      shiny::textInput("another_input", "Another input"),
      shiny::actionButton("go_button", "Go!")
    ),
    server = function(input, output, session) {
      changeServer("change_module")
    }
  )
}

---

Add the shinyfocus JavaScript to shiny

Description

Add the shinyfocus.js script to a shiny app exactly once. Adding this script setups up the object used to detect changes in focus.

Usage

shinyfocus_js_dependency()

Value

An htmltools::htmlDependency(), which shiny uses to add the shinyfocus.js script exactly once.

Examples

shinyfocus_js_dependency()

---