Button

Type     [gd]	class
Inheritance	Button ➝ Group ➝ Display ➝ Object
Overview	Creates text button that can be tapped. It is a Group that contains RoundRect (or Rect or Circle) and Text objects. Default click effect is invertin color.
See also [bg]	Group, Display

Syntax

local btn = Button(text [, onPressfunc] [, option] ])

• text (required : string )  string that is displayed on button

• onPressFunc (optional : function )  function that is called when the button is pressed.

The first parameter of the called function is button object.

The second parameter of the called function is touch event table.

• option (optional : table) = {

fontSize = n, -- default : 50 pixels

textColor = color,     -- default color : Color.WHITE

margin = n, -- in pixels, default value is fontsize*0.5 pixels

fill = color,                 -- background color (default : Color.GREEN)

strokeColor = color, -- default color : Color.LIGHT_GREEN

strokeWidth = n, -- border line width in pixel (default: fontsize*0.15 pixels)

effect = string, -- 'invertColor'(default), 'shrink', 'expand', 'none'

           -- shape of the background

shape = string         -- 'roundRect'(default), 'rect', 'circle'

width = n, -- width of the button if shape is 'roundRect' or 'rect'

height = n, -- height of the button if shape is 'roundRect' or 'rect'

radius = n, -- radius of the button if shape is 'circle'

}

Note : The width and height of the button is automatically set using the fontSize and margin. If the user want to force the width/height regardless of the font size, set width or height field of option table.

Methods

(getter) method	description	return
obj:getString()	return current text string of the button	string
obj:getFontSize()	return current font size of the button text	number

(setter) method	description	return
obj:setString(str)	change the text of button (button is resized if necessary)	self
obj:setFontSize(n)	change font size of the text on button (button is resized if necessary)	self
obj:setTextColor(color)	set color of the text with Color object	self
obj:setStrokeWidth(n)	set width of the outline of the button	self
obj:setStrokeColor(color)	set color of the outline of the button with Color object	self
obj:fill(color)	set color of inner area with Color object	self
obj:setWidth(n)	force button width to n regardless of font size (If button has circular shape, this method does not work)	self
obj:setHeight(n)	force button height to n (If button has circular shape, this method does not work)	self
obj:setRadius(n)	change the radius of button (If button has rectangular shape, this method does not work)	self

user-defined method

custom method	description	return
obj:onPress(e)	define callback function that is called when the button is pressed.	self
obj:onRelease(e)	define callback function that is called when the button is released.	self

Examples

local btn1 = Button('None') -- nothing happens when pressed local btn2 = Button('None',{fontSize=100}) -- nothing happens when pressed

-- define callback function when button is created local btn = Button('Click me', function(self,e)     print('pressed') end) --or -- create button and define callback functions later local btn2 = Button('Click me', {fontSize=100}) function btn2:onPress(e)     print('pressed') end function btn2:onRelease(e)     print('released') end

-- set predefined callback function when button is created local function onPress(self,e)     print('clicked') end local btn = Button('Click me', onPress)

-- define callback function when button is created and add onRelease() method later. local btn = Button('Click me', function(self,e)     print('pressed') end, {fontSize=100, effect=false}) function btn:onRelease(e)     print('released') end