event.id

概述

选定触控的唯一标识符，它可以让您在不同触控事件中区分多个触控。这会唯一标识接触屏幕的指定手指，因为该触控会改变状态，例如，当触控生成新的触控事件（例如 “已移动”、“已结束”等）时。

示例

system.activate( "multitouch" )

local object = display.newImage( "ball.png" )
object.numTouches = 0

function object:touch( event )
    if event.phase == "began" then
        display.getCurrentStage():setFocus( self, event.id )
        self.numTouches = self.numTouches + 1

        if self.numTouches >= 2 then
            print( "This object is being multi-touched." )
        end
    
    elseif event.phase == "cancelled" or event.phase == "ended" then

        self.numTouches = self.numTouches - 1

        if self.numTouches <= 0 then
            display.getCurrentStage():setFocus( nil )
        end
    end
    return true
end
object:addEventListener( "touch", object )