display:touch()

Type	user method of Display class	[gd]
Overview	User-defined function	[bgl
Return value
See also	Display class

Overview 

The onTouch() method of a Display object can be defined.

This method handles touch events and is called when the events are occurred.

Syntax

function dispobj:onTouch(e)     …     … end

Here, dispobj is a Display object such as image or shapes. The argument e is a table that has the following fields.

        • phase : (string) this has four cases as follows.

                • 'begin'  : touch began

                • 'move'  : touch point is moving.

                • 'end'     : touch ended

                • 'cancel' : touch cancelled

        • x     : the x-coordinates of touch point

        • y     : the y-coordinates of touch point

        • dx   : the deviations of x coordinates at 'move' phase.  At 'begin' phase, it is zero.

        • dy   : the deviations of y coordinates at 'move' phase. At 'begin' phase, it is zero.

        • id    : touch id (in case of multiple touches, this distinguishes between them)

Examples

 

local moon = Image('moon.png') function moon:onTouch(e)     if e.phase=='begin' then         self:setScale(1.2):setDrot(2)     elseif e.phase == 'move' then         local tx = self:getX()+e.dx         local ty = self:getY()+e.dy         self:setXY(tx,ty)     elseif e.phase=='end' or e.phase=='cancel' then         self:setScale(1):setDrot(0)     end end