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ContextActionService

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Service

Allows an experience to bind user input to contextual actions, or actions that are only enabled under some condition or period of time. For example, allowing a player to open a door only while close by. In code, an action is simply a string (the name of the action) used by the service to differentiate between unique actions. The action string is provided to BindAction and UnbindAction, among other member functions. If two actions are bound to the same input, the most recently bound will take priority. When the most recent action is unbound, the one bound before that takes control again. Since this service deals with user input, you can only use it in client-side LocalScripts.

What is a context?

A context is simply a condition during which a player may perform some action. Some examples include holding a Tool, being seated in a car or standing near a door. Whatever the case may be, it is up to your LocalScripts to call BindAction when the context is entered and UnbindAction when the context is left.

What is an action?

An action is simply some input that can be performed by the player while in that context. Such an action could open/close some menu, trigger a secondary tool action or send a request to the server using RemoteFunction:InvokeServer(). An action is identified by a unique string as the first parameter of both BindAction and UnbindAction. The string can be anything, but it should reflect the action being performed, not the input being used. For example, don't use "KeyH" as an action name - use "CarHorn" instead. It is best to define your actions as a constant at the top of your script since you will use it in at least three different places in your code.

Why bind actions contextually?

It's better to use ContextActionService's BindAction than UserInputService.InputBegan for most cases. For UserInputService.InputBegan, your connected function would have to check if the player is in the context of the action being performed. In most cases, this is harder than just calling a function when a context is entered/ left. For example, if you want to have the H key trigger a car horn sound while the player is sitting in it, the player might type "hello" in chat or otherwise use the H key for something else. It is harder to determine if something else is using the H key (like chat) - the car might honk when the player didn't mean to. If you instead use BindAction and UnbindAction when the player enters/leaves the car, ContextActionService will make sure that H key presses trigger the honk action only when it is the most recently bound action. If something else (like chat) takes control, you won't have to worry about checking that.

Inspecting Bound Actions

To see a list of actions and their bound inputs, you can inspect the "Action Bindings" tab in the Developer Console (F9 while in game). This shows all bindings - including those bound by Roblox CoreScripts and default camera/control scripts too. This is useful for debugging: check if your actions are being bound/unbound at the correct times, or if some other action is stealing input from your actions. For example, if you are attempting to bind WASD, it may be the case that default character movement scripts are binding over those same keys. Similarly, the camera control script can steal right-click input if the script runs after yours.

Keyboardless Input

This service is especially useful for supporting gamepad and touch input. For gamepad input, you might choose to bind the B button to an action that returns the user to the previous menu when they entire another menu. For touch, on-screen touch buttons can be used in place of key presses: these buttons display only while the action is bound, and the position, text and/or images of these buttons can be configured through this service. They're somewhat limited in the amount of customization provided by this service; it's usually a better idea to make your own on-screen buttons using ImageButton or TextButton.

Code Samples

ContextActionService Tool Reload
local ContextActionService = game:GetService("ContextActionService")



local ACTION_RELOAD = "Reload"



local tool = script.Parent



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_RELOAD and inputState == Enum.UserInputState.Begin then

		print("Reloading!")

	end

end



tool.Equipped:Connect(function()

	ContextActionService:BindAction(ACTION_RELOAD, handleAction, true, Enum.KeyCode.R)

end)



tool.Unequipped:Connect(function()

	ContextActionService:UnbindAction(ACTION_RELOAD)

end)

Summary

Properties

Methods

BindAction(actionName: string, functionToBind: function, createTouchButton: boolean, inputTypes: Tuple): void  

Bind user input to an action given an action handling function.

BindActionAtPriority(actionName: string, functionToBind: function, createTouchButton: boolean, priorityLevel: number, inputTypes: Tuple): void  

Behaves like BindAction but also allows a priority to be assigned to the bound action for overlapping input types (higher before lower).

BindActivate(userInputTypeForActivation: UserInputType, keyCodesForActivation: Tuple): void  

Bind a KeyCode with a specific UserInputType to trigger Tool.Activation and ClickDetector events.

GetAllBoundActionInfo(): table  

Get a table of information about all bound actions (key is the name passed to BindAction, value is a table from GetBoundActionInfo when called with the key).

GetBoundActionInfo(actionName: string): table  

Get a table of information about a bound action given its name originally passed to BindAction.

GetCurrentLocalToolIcon(): string  

Return the BackpackItem.TextureId of a Tool currently equipped by the Player.

SetDescription(actionName: string, description: string): void  

Given the name of a bound action with a touch button, sets the description of the action.

SetImage(actionName: string, image: string): void  

If actionName key contains a bound action, then image is set as the image of the touch button.

SetPosition(actionName: string, position: UDim2): void  

Given the name of a bound action with a touch button, sets the position of the button within the ContextButtonFrame.

SetTitle(actionName: string, title: string): void  

Given the name of a bound action with a touch button, sets the text shown on the button.

UnbindAction(actionName: string): void  

Unbind an action from input given its name.

UnbindActivate(userInputTypeForActivation: UserInputType, keyCodeForActivation: KeyCode): void  

Unbind a KeyCode with a specific UserInputType from triggering Tool.Activation when bound with ContextActionService:BindActivate().

UnbindAllActions(): void  

Removes all functions bound. No actionNames will remain. All touch buttons will be removed.

GetButton(actionName: string): Instance  YIELDS

Retrieves a ImageButton of a bound action that had a touch input button created.

Events

LocalToolEquipped(toolEquipped: Instance): RBXScriptSignal  

Fires when the current player equips a Tool.

LocalToolUnequipped(toolUnequipped: Instance): RBXScriptSignal  

Fires when the current player unequips a Tool.

Properties

Methods

BindAction

void

Bind an action to user input given an action handling function. Upon a matching input being performed, the action handler function will be called with the arguments listed below. Valid input enum items include those within the following: KeyCode, UserInputType or PlayerActions . Call this function when a player enters the context in which an action can be performed. When the player leaves the context, call UnbindAction with the same actionName. You can manually call the action handling function of an action by using CallFunction.

The code sample below shows how a Sound can be played while a key (H), game pad button, or touch screen button is pressed.

local ContextActionService = game:GetService("ContextActionService")



-- A car horn sound

local honkSound = Instance.new("Sound", workspace)

honkSound.Looped = true

honkSound.SoundId = "rbxassetid://9120386436"



local function handleAction(actionName, inputState, inputObject)

	if actionName == "HonkHorn" then

		if inputState == Enum.UserInputState.Begin then

			honkSound:Play()

		else

			honkSound:Pause()

		end

	end

end



-- When the player sits in the vehicle:

ContextActionService:BindAction("HonkHorn", handleAction, true, Enum.KeyCode.H, Enum.KeyCode.ButtonY)



-- When the player gets out:

ContextActionService:UnbindAction("HonkHorn")

Action Handler Parameters

The action handler functions are called with the following parameters:

#TypeDescription
1stringThe same string that was originally passed to BindAction†
2UserInputStateThe state of the input (Begin, Change, End or Cancel)*
3InputObjectAn object that contains information about the input (varies based on UserInputType)

† This allows one function to handle multiple actions at once, if necessary. *Cancel is sent if some input was in-progress and another action bound over the in-progress input, or if the in-progress bound action was unbound.

Action Bindings Stack

Action bindings behave like a stack: if two actions are bound to the same user input, the most recently bound action handler will be used. If an action handler returns ContextActionResult.Pass, the next most recently bound action handler will be called, and so on until a handler sinks the input (by returning nil or ContextActionResult.Sink). When UnbindAction is called, the action handler is removed from the stack. This stack behavior can be overridden using BindActionAtPriority, where an additional priority parameter after createTouchButton may override the order in which actions are bound (higher before lower).

Touch Buttons

In addition to input types, this function's third parameter controls whether a button is created for TouchEnabled devices. Upon the first touch button's creation, a ScreenGui named "ContextActionGui" is added to the PlayerGui. Inside the ScreenGui is a Frame called "ContextButtonFrame" is added. It is in this frame in which ImageButtons for bound actions are parented; you can use GetButton to retrieve such buttons for customization.

Parameters

actionName: string

A string representing the action being performed (e.g. "HonkHorn" or "OpenDoor").

functionToBind: function

The action-handling function, called with the following parameters when the bound inputs are triggered: string (actionName), UserInputState and an InputObject.

createTouchButton: boolean

Whether a GUI button should be created for the action on touch input devices.

inputTypes: Tuple

Any number of KeyCode or UserInputType representing the inputs to bind to the action.


Returns

void

Code Samples

ContextActionService Tool Reload
local ContextActionService = game:GetService("ContextActionService")



local ACTION_RELOAD = "Reload"



local tool = script.Parent



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_RELOAD and inputState == Enum.UserInputState.Begin then

		print("Reloading!")

	end

end



tool.Equipped:Connect(function()

	ContextActionService:BindAction(ACTION_RELOAD, handleAction, true, Enum.KeyCode.R)

end)



tool.Unequipped:Connect(function()

	ContextActionService:UnbindAction(ACTION_RELOAD)

end)
General Action Handler
local ContextActionService = game:GetService("ContextActionService")



local function handleAction(actionName, inputState, inputObj)

	if inputState == Enum.UserInputState.Begin then

		print("Handling action: " .. actionName)

		print(inputObj.UserInputType)

	end



	-- Since this function does not return anything, this handler will

	-- "sink" the input and no other action handlers will be called after

	-- this one.

end



ContextActionService:BindAction("BoundAction", handleAction, false, Enum.KeyCode.F)
Stacked Action Handlers
local ContextActionService = game:GetService("ContextActionService")



-- Define an action handler for FirstAction

local function actionHandlerOne(actionName, inputState, _inputObj)

	if inputState == Enum.UserInputState.Begin then

		print("Action Handler One: " .. actionName)

	end

	-- This action handler returns nil, so it is assumed that

	-- it properly handles the action.

end



-- Binding the action FirstAction (it's on the bottom of the stack)

ContextActionService:BindAction("FirstAction", actionHandlerOne, false, Enum.KeyCode.Z, Enum.KeyCode.X, Enum.KeyCode.C)



-- Define an action handler for SecondAction

local function actionHandlerTwo(actionName, inputState, inputObj)

	if inputState == Enum.UserInputState.Begin then

		print("Action Handler Two: " .. actionName)

	end



	if inputObj.KeyCode == Enum.KeyCode.X then

		return Enum.ContextActionResult.Pass

	else

		-- Returning nil implicitly Sinks inputs

		return Enum.ContextActionResult.Sink

	end

end



-- Binding SecondAction over the first action (since it bound more recently, it is on the top of the stack)

-- Note that SecondAction uses the same keys as

ContextActionService:BindAction("SecondAction", actionHandlerTwo, false, Enum.KeyCode.Z, Enum.KeyCode.X)

BindActionAtPriority

void

BindActionAtPriority behaves like BindAction but also allows a priority to be assigned to the bound action. If multiple actions are bound to the same input, the higher priority function is called regardless of the order in which the actions were bound. In other words, this function overrides the normal "stack" behavior of BindAction.

Parameters

actionName: string

A string representing the action being performed (e.g. "HonkHorn" or "OpenDoor").

functionToBind: function

The action-handling function, called with the following parameters when the bound inputs are triggered: string (actionName), UserInputState and an InputObject.

createTouchButton: boolean

Whether a GUI button should be created for the action on touch input devices.

priorityLevel: number

The priority level at which the action should be bound (higher considered before lower).

inputTypes: Tuple

Any number of Enum.KeyCode or Enum.UserInputType representing the inputs to bind to the action.


Returns

void

Code Samples

ContextActionService BindAction Priorities
local ContextActionService = game:GetService("ContextActionService")



local INPUT_KEY1 = Enum.KeyCode.Q

local INPUT_KEY2 = Enum.KeyCode.E



local function handleThrow(_, inputState, _)

	if inputState ~= Enum.UserInputState.Begin then

		return Enum.ContextActionResult.Pass

	end



	print("Throw")

	return Enum.ContextActionResult.Sink

end



local function handlePunch(_, inputState, _)

	if inputState ~= Enum.UserInputState.Begin then

		return Enum.ContextActionResult.Pass

	end



	print("Punch")

	return Enum.ContextActionResult.Sink

end



-- Without specifying priority, the most recently bound action is called first,

-- so pressing INPUT_KEY1 prints "Punch" and then sinks the input.

ContextActionService:BindAction("DefaultThrow", handleThrow, false, INPUT_KEY1)

ContextActionService:BindAction("DefaultPunch", handlePunch, false, INPUT_KEY1)



-- Here we bind both functions in the same order as above, but with explicitly swapped priorities.

-- That is, we give "Throw" a higher priority of 2 so it will be called first,

-- despite "Punch" still being bound more recently.

-- Pressing INPUT_KEY2 prints "Throw" and then sinks the input.

ContextActionService:BindActionAtPriority("PriorityThrow", handleThrow, false, 2, INPUT_KEY2)

ContextActionService:BindActionAtPriority("PriorityPunch", handlePunch, false, 1, INPUT_KEY2)

BindActivate

void

Bind an KeyCode that can be used with a UserInputType to activate ClickDetector events and Tool objects. When the given key/button is pressed, it fires the Mouse.Button1Down event on the mouse sent to Tool.Equipped. This in turn fires the Tool.Activated event if Tool.ManualActivationOnly is not set to true. For gamepad input, this function is called by the default control scripts in order to bind the ButtonR2 KeyCode.

Note that the UserInputType specified must be Keyboard or Gamepad1 through Gamepad8 in order to be valid.

Parameters

userInputTypeForActivation: UserInputType

Must be Keyboard or Gamepad1 through Gamepad8.

keyCodesForActivation: Tuple

Returns

void

GetAllBoundActionInfo

table

GetAllBoundActioninfo returns a table which maps all actions' names (those originally passed to BindAction) to a table returned by GetBoundActionInfo when called with the action name itself. Using this function, you can inspect all presently bound actions. This is useful when debugging their priority levels or stack orders.


Returns

table

GetBoundActionInfo

table

GetBoundActionInfo returns a table with the following keys describing a bound action given its name. To get the same information for all actions at once, use GetAllBoundActionInfo.

NameTypeDescription
stackOrdernumber

Describes the index of the action on the stack (increasing)

priorityLevel*number

Describes the priority level of the action

createTouchButtonbool

Describes whether a touch button should be created on TouchEnabled devices

inputTypestable

The input types passed to BindAction for which this action will trigger

description†string

The description of action set by SetDescription

title†string

The title of the action set by SetTitle

image†string

The image of the action's touch button set by SetImage

* Priority level will still be included even if BindActionAtPriority wasn't used - by default it will be 2000.

† Indicates that this field will be nil if the associated method was not called for the given action.

Parameters

actionName: string

Returns

table

GetCurrentLocalToolIcon

string

GetCurrentLocalToolIcon will return the BackpackItem.TextureId of a Tool currently equipped by the Player, or nil if there is no such Tool or if the player lacks a Character.


Returns

string

A content string from the Tool's TextureId, or nil if one could not be found.

SetDescription

void

SetDescription will set the description of an action bound by BindAction. In a list of available actions, this would be text that describes the given action.

Although the name may suggest that this method is related to the family of functions that customize a touch button for actions that create them (SetTitle, SetImage and SetPosition), this method does not affect such a button. This method merely sets a text description of an action, and nothing more.

Parameters

actionName: string

The name of the action originally passed to BindAction.

description: string

A text description of the action, such as "Honk the car's horn" or "Open the inventory".


Returns

void

Code Samples

ContextActionService Touch Button
local ContextActionService = game:GetService("ContextActionService")



local ACTION_INSPECT = "Inspect"

local INPUT_INSPECT = Enum.KeyCode.E

local IMAGE_INSPECT = "rbxassetid://1826746856" -- Image of a speech bubble with ? in it



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_INSPECT and inputState == Enum.UserInputState.End then

		print("Inspecting")

	end

end



-- For touch devices, a button is created on-screen automatically via the 3rd parameter

ContextActionService:BindAction(ACTION_INSPECT, handleAction, true, INPUT_INSPECT)

-- We can use these functions to customize the button:

ContextActionService:SetImage(ACTION_INSPECT, IMAGE_INSPECT)

ContextActionService:SetTitle(ACTION_INSPECT, "Look")

ContextActionService:SetDescription(ACTION_INSPECT, "Inspect something.")

ContextActionService:SetPosition(ACTION_INSPECT, UDim2.new(0, 0, 0, 0))

-- We can manipulate the button directly using ContextActionService:GetButton

local imgButton = ContextActionService:GetButton(ACTION_INSPECT)

if imgButton then -- Remember: non-touch devices won't return anything!

	imgButton.ImageColor3 = Color3.new(0.5, 1, 0.5) -- Tint the ImageButton green

end

SetImage

void

SetPosition will set the text shown on a touch button created by BindAction. Specifically, this sets the ImageLabel.Image property of the ImageLabel within the ImageButton that would be returned by GetButton. If no such bound action exists (e.g. nothing is returned by GetButton), this function does nothing and throws no error.

This function is part of a family of methods that customize the touch button of an action. Others in this family include SetPosition and SetTitle.

Parameters

actionName: string

The name of the action originally passed to BindAction.

image: string

The value to which the Image property should be set.


Returns

void

Code Samples

ContextActionService Touch Button
local ContextActionService = game:GetService("ContextActionService")



local ACTION_INSPECT = "Inspect"

local INPUT_INSPECT = Enum.KeyCode.E

local IMAGE_INSPECT = "rbxassetid://1826746856" -- Image of a speech bubble with ? in it



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_INSPECT and inputState == Enum.UserInputState.End then

		print("Inspecting")

	end

end



-- For touch devices, a button is created on-screen automatically via the 3rd parameter

ContextActionService:BindAction(ACTION_INSPECT, handleAction, true, INPUT_INSPECT)

-- We can use these functions to customize the button:

ContextActionService:SetImage(ACTION_INSPECT, IMAGE_INSPECT)

ContextActionService:SetTitle(ACTION_INSPECT, "Look")

ContextActionService:SetDescription(ACTION_INSPECT, "Inspect something.")

ContextActionService:SetPosition(ACTION_INSPECT, UDim2.new(0, 0, 0, 0))

-- We can manipulate the button directly using ContextActionService:GetButton

local imgButton = ContextActionService:GetButton(ACTION_INSPECT)

if imgButton then -- Remember: non-touch devices won't return anything!

	imgButton.ImageColor3 = Color3.new(0.5, 1, 0.5) -- Tint the ImageButton green

end

SetPosition

void

SetPosition sets the position of a touch button created by BindAction. Specifically, this sets the GuiObject.Position property of the ImageButton that would be returned by GetButton. If no such bound action exists (e.g. nothing is returned by GetButton), this function does nothing and throws no error.

This function is part of a family of methods that customize the touch button of an action. Others in this family include SetImage and SetTitle.

Parameters

actionName: string

The name of the action originally passed to BindAction.

position: UDim2

The position within the ContextButtonFrame.


Returns

void

Code Samples

ContextActionService Touch Button
local ContextActionService = game:GetService("ContextActionService")



local ACTION_INSPECT = "Inspect"

local INPUT_INSPECT = Enum.KeyCode.E

local IMAGE_INSPECT = "rbxassetid://1826746856" -- Image of a speech bubble with ? in it



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_INSPECT and inputState == Enum.UserInputState.End then

		print("Inspecting")

	end

end



-- For touch devices, a button is created on-screen automatically via the 3rd parameter

ContextActionService:BindAction(ACTION_INSPECT, handleAction, true, INPUT_INSPECT)

-- We can use these functions to customize the button:

ContextActionService:SetImage(ACTION_INSPECT, IMAGE_INSPECT)

ContextActionService:SetTitle(ACTION_INSPECT, "Look")

ContextActionService:SetDescription(ACTION_INSPECT, "Inspect something.")

ContextActionService:SetPosition(ACTION_INSPECT, UDim2.new(0, 0, 0, 0))

-- We can manipulate the button directly using ContextActionService:GetButton

local imgButton = ContextActionService:GetButton(ACTION_INSPECT)

if imgButton then -- Remember: non-touch devices won't return anything!

	imgButton.ImageColor3 = Color3.new(0.5, 1, 0.5) -- Tint the ImageButton green

end

SetTitle

void

SetTitle will set the text shown on a touch button created by BindAction. Specifically, this sets the TextLabel.Text property of a TextLabel within the ImageButton that would be returned by GetButton. If no such bound action exists (e.g. nothing is returned by GetButton), this function does nothing and throws no error.

This function is part of a family of methods that customize the touch button of an action. Others in this family include SetImage and SetPosition.

Parameters

actionName: string

The name of the action originally passed to BindAction.

title: string

The text to display on the button.


Returns

void

Code Samples

ContextActionService Touch Button
local ContextActionService = game:GetService("ContextActionService")



local ACTION_INSPECT = "Inspect"

local INPUT_INSPECT = Enum.KeyCode.E

local IMAGE_INSPECT = "rbxassetid://1826746856" -- Image of a speech bubble with ? in it



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_INSPECT and inputState == Enum.UserInputState.End then

		print("Inspecting")

	end

end



-- For touch devices, a button is created on-screen automatically via the 3rd parameter

ContextActionService:BindAction(ACTION_INSPECT, handleAction, true, INPUT_INSPECT)

-- We can use these functions to customize the button:

ContextActionService:SetImage(ACTION_INSPECT, IMAGE_INSPECT)

ContextActionService:SetTitle(ACTION_INSPECT, "Look")

ContextActionService:SetDescription(ACTION_INSPECT, "Inspect something.")

ContextActionService:SetPosition(ACTION_INSPECT, UDim2.new(0, 0, 0, 0))

-- We can manipulate the button directly using ContextActionService:GetButton

local imgButton = ContextActionService:GetButton(ACTION_INSPECT)

if imgButton then -- Remember: non-touch devices won't return anything!

	imgButton.ImageColor3 = Color3.new(0.5, 1, 0.5) -- Tint the ImageButton green

end

UnbindAction

void

UnbindAction will unbind an action by name from user inputs so that the action handler function will no longer be called. Call this function when the context for some action is no longer applicable, such as closing a user interface, exiting a car or unequipping a Tool. See BindAction for more information on how bound actions operate.

This function will not throw an error if there is no such action bound with the given string. Using GetAllBoundActionInfo or the Developer Console's "Action Bindings" tab, you can find out what actions are presently bound.

Parameters

actionName: string

Returns

void

Code Samples

ContextActionService Tool Reload
local ContextActionService = game:GetService("ContextActionService")



local ACTION_RELOAD = "Reload"



local tool = script.Parent



local function handleAction(actionName, inputState, _inputObject)

	if actionName == ACTION_RELOAD and inputState == Enum.UserInputState.Begin then

		print("Reloading!")

	end

end



tool.Equipped:Connect(function()

	ContextActionService:BindAction(ACTION_RELOAD, handleAction, true, Enum.KeyCode.R)

end)



tool.Unequipped:Connect(function()

	ContextActionService:UnbindAction(ACTION_RELOAD)

end)

UnbindActivate

void

UnbindActivate unbinds an KeyCode used with an UserInputType for activating a Tool (or a HopperBin) using BindActivate. This function essentially undoes the action performed by that function.

Parameters

userInputTypeForActivation: UserInputType

The same UserInputType originally sent to BindActivate.

keyCodeForActivation: KeyCode

The same KeyCode originally sent to BindActivate.

Default Value: "Unknown"

Returns

void

UnbindAllActions

void

Removes all functions bound. No actionNames will remain. All touch buttons will be removed. If a button was manipulated manually there is no guarantee it will be cleaned up.


Returns

void

GetButton

Instance
Yields

GetButton returns the ImageButton created by BindAction if its third parameter was true and the device is TouchEnabled. The only parameter to this function must match exactly the name of the action originally sent to BindAction.

If no such action was bound or if a button was not created, this function returns nil.

Parameters

actionName: string

The name of the action originally passed to BindAction.


Returns

Instance

An ImageButton created by BindAction.

Events

LocalToolEquipped

Fires when the current player equips a Tool.

Parameters

toolEquipped: Instance

LocalToolUnequipped

Fires when the current player unequips a Tool.

Parameters

toolUnequipped: Instance