OOP and eventListener in Lua (Corona SDK)

问题

My first steps in Corona SDK and first troubles. Trying to make two boxes which I can move by following this OOP tutorial, but this doesn't work. I have successfully created two boxes but only one is movable. When I try to move another one it doesn't moved but first one is moving. Guess there's problem with scopes but can't figure where is exactly. Thank you for any help.

tile.lua source code:

module (..., package.seeall)


function new(initX, initY)

    local scrnWidth = display.stageWidth
local scrnHeight  = display.stageHeight
local squareSize = (scrnWidth*0.9)/4

   local tile = display.newRect( initY, initY, squareSize, squareSize )

   function move(direction)
       if direction == "left" then
            transition.moveTo(tile, {x = tile.x+squareSize,y = tile.y,time = 200})
    elseif direction == "right" then
            transition.moveTo(tile, {x = tile.x-squareSize,y = tile.y,time = 200})
    elseif direction == "up" then
            transition.moveTo(tile, {x = tile.x,y = tile.y-squareSize,time = 200})
    elseif direction == "down" then
            transition.moveTo(tile, {x = tile.x,y = tile.y+squareSize,time = 200})
    end
   end


function tile:touch(event)
        if event.phase == "began" then
            display.getCurrentStage():setFocus( tile )
                beginX = event.x
                beginY = event.y
        end

        if event.phase == "ended"  then
                endX = event.x
                endY = event.y
            display.getCurrentStage():setFocus(nil)

                checkSwipeDirection();
        end
    end

function checkSwipeDirection()

        xDistance =  math.abs(endX - beginX) -- math.abs will return the absolute, or non-negative value, of a given value. 
        yDistance =  math.abs(endY - beginY)

        if xDistance > yDistance then
                if beginX > endX then
                        move("right",tile)
                else 
                       move("left",tile)

                end
        else 
                if beginY > endY then
                        move("up",tile)
                else 
                        move("down",tile)
                end
        end

end

tile:addEventListener("touch", tile)
   return tile

end

and I create objects by using the following code in main.lua:

    local tileConst = require("tile")
    local tile1 = tileConst.new(100,100)
    local tile2 = tileConst.new(200,200)

回答1:

In your tile.lua scene, declare a variable to hold touched sprite just below module (..., package.seeall):

local touchedSprite -- my temporary sprite variable

Then assign the target sprite to the above variable inside the function as:

function tile:touch(event)
    touchedSprite = event.target -- Assigning target to variable
    ...
end

Now change the function move as follows:

function move(direction)
  if direction == "left" then
    transition.to(touchedSprite, {x = touchedSprite.x+squareSize,y = touchedSprite.y,time = 200})
  elseif direction == "right" then
    transition.to(touchedSprite, {x = touchedSprite.x-squareSize,y = touchedSprite.y,time = 200})
  elseif direction == "up" then
    transition.to(touchedSprite, {x = touchedSprite.x,y = touchedSprite.y-squareSize,time = 200})
  elseif direction == "down" then
    transition.to(touchedSprite, {x = touchedSprite.x,y = touchedSprite.y+squareSize,time = 200})
  end
end

Note that I've changed transition.moveTo to transition.to and your transition tile to touchedSprite(target).

Keep Coding.................. :)

来源：https://stackoverflow.com/questions/21028931/oop-and-eventlistener-in-lua-corona-sdk

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lua

corona