Android 在电晕中画线并擦掉

我用下面的代码画了一条线

但如果手指碰到同一条线，我想抹掉这条线。。有什么想法吗

function drawLine( event )
  if(event.phase == "ended") then
    line = display.newLine(event.xStart, event.yStart, event.x, event.y)
    line:setColor(255,0,0)
    line.width = 5
  end
end
Runtime:addEventListener("touch", drawLine)

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简单。将该线设为传感器，用户一接触该线，就将其从组中移除或删除该对象

physics.addBody( line, { isSensor = true } ) 
someGroup:insert(line)
line.collision = removeLine   --some function that removes the line from the group someGroup
line:addEventListener(""touch"", line)