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Cocos2dx-lua Keyboard Listening

Introduction

In this guide, we will learn how to implement keyboard event listening using Lua in Cocos2dx. This is essential for controlling game characters or implementing various game controls.

Setting Up Keyboard Event Listener

To enable keyboard event handling, you need to add an event listener for keyboard events. The following code shows how to set this up:

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-- Create a keyboard event listener
local function onKeyPressed(keyCode, event)
print("Key Pressed: " .. keyCode)
end

local function onKeyReleased(keyCode, event)
print("Key Released: " .. keyCode)
end

local listener = cc.EventListenerKeyboard:create()
listener:registerScriptHandler(onKeyPressed, cc.Handler.EVENT_KEYBOARD_PRESSED)
listener:registerScriptHandler(onKeyReleased, cc.Handler.EVENT_KEYBOARD_RELEASED)

local eventDispatcher = self:getEventDispatcher()
eventDispatcher:addEventListenerWithSceneGraphPriority(listener, self)

Explanation

  • onKeyPressed: This function gets called whenever a key is pressed. You can customize it to perform actions like moving a character or jumping.
  • onKeyReleased: This function handles actions when a key is released, useful for stopping movements or other behaviors.

Common Use Cases

  • Character Movement: Use arrow keys to control the direction of the character.
  • Game Pause/Resume: Bind a key to pause and resume the game.
  • Menu Navigation: Use keyboard shortcuts to navigate through in-game menus.

Full Example Code

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local MainScene = class("MainScene", cc.load("mvc").ViewBase)

function MainScene:onCreate()
-- Setup keyboard listener
local function onKeyPressed(keyCode, event)
if keyCode == cc.KeyCode.KEY_A then
print("A key pressed - Move Left")
elseif keyCode == cc.KeyCode.KEY_D then
print("D key pressed - Move Right")
end
end

local function onKeyReleased(keyCode, event)
print("Key Released: " .. keyCode)
end

local listener = cc.EventListenerKeyboard:create()
listener:registerScriptHandler(onKeyPressed, cc.Handler.EVENT_KEYBOARD_PRESSED)
listener:registerScriptHandler(onKeyReleased, cc.Handler.EVENT_KEYBOARD_RELEASED)

local eventDispatcher = self:getEventDispatcher()
eventDispatcher:addEventListenerWithSceneGraphPriority(listener, self)
end

return MainScene

Notes

Make sure that your Cocos2dx project is properly configured to support keyboard events. Depending on the platform, some keys may behave differently.

Conclusion

By following the steps in this guide, you should be able to implement keyboard listening in your Cocos2dx-lua project effectively. Feel free to customize the code for more advanced interactions!

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