How to assign a function in Lua for a randomly generated numbers

问题

First I stored 10 images in array(i.e., table) from 1-10 as key values and I create a random number using math.random function between 0-9.,
and I need to access the image that is stored in array by the value created by random function, and assign the touch function for the particular image file alone.,

Ex:

If the random function creates number as "5" I need to move the image 5.png that is stored in array index as 5 .,other images except 5.png should not use touch function., (i.e., they are not allowed to move in screen but need to display in screen)

Here is my code:

local myText1 = display.newText(tostring(no1),130, 100, "Jokerman", 36); 
myText1:setTextColor(238,18,137)
print("text value1 :",no1)

local myText2 = display.newText(tostring(ran),130, 140, "Jokerman", 36); 
myText2:setTextColor(238,18,137)
print("text value2 :",ran)

result = no1 + ran;
print("Result is:" ,result)

local myres = result
print("myresultant string is -->" ,myres)

myres1 = myres % 10;
myres2 = math.floor(myres / 10);
print(myres1)
print(myres2)
--assigning values
    dig1 = myres1
    dig2 = myres2

 function dig1:touch(event)
    local t = event.target
    -- printTouch(event)
    local phase = event.phase
        if phase == "began" then
            -- Make target the top-most object
                local parent = t.parent
                parent:insert(t)
                display.getCurrentStage():setFocus(t)
    -- This flag is to prevent spurious events being sent to the target
                t.isFocus = true
    -- Store initial position
                t.x0 = event.x - t.x
                t.y0 = event.y - t.y
    -- Make myObject temporarily kinematic
                event.target.bodyType = "kinematic"
    -- Stop current motion, if any
                event.target:setLinearVelocity(0,0)
                event.target.angularVelocity = 0
        elseif t.isFocus then
                if phase == "moved" then
                    t.x = event.x - t.x0
                    t.y  = event.y - t.y0

        elseif phase == "ended" or phase == "cancelled" then
                if currentTarget ~= nil and isHighlighted then
                -- Move piece to target
                    transition.to(t,{
                        time = 150,
                        x = currentTarget.x,
                        y = currentTarget.y
                    })
                    currentTarget = nil
                    isHighlighted = false
                end
            display.getCurrentStage():setFocus(nil)
            t.isFocus = false
            -- Switch body type back to "static"
            event.target.bodyType = "static"
        end
    end

    return true
end

dig1:addEventListener("touch",dig1)

回答1:

Sorry I am still not clear about the problem. But can't be clear in comments, so trying this answer.

Here is what I think you are trying to do, in pseudocode:

-- init (startup)
function touch(image) 
    ... do something to image ...
end

function noTouch(image) 
    end -- nothing to touch

imageArray = table of 10 images
each image in imageArray is of "class" Image
for each image in imageArray do
    image.touch = noTouch -- a "do nothing" function
end
-- init completed

-- later, this gets called:
function touchRandomImage()
    index = random number between 1 and 10 (incl)
    moveImage = imageArray[index]
    moveImage.touch = yourTouchFunction
end

Later when some other code calls image:touch() (or image.touch(image), same thing), only the randomly selected image as per above will use the special touch function, all the others will have the do-nothing noTouch.

If touchRandomImage() can be called multiple times, you have to keep track of the "previous" randomly selected image so that you can reset its touch field to be the noTouch function:

function touchRandomImage()
    -- prevIndex is a global, or a field etc
    if prevIndex ~= nil then
        imageArray[prevIndex].touch = noTouch
        prevIndex = nil -- in case exception etc
    newIndex = random number between 1 and 10 (incl)
    moveImage = imageArray[newIndex]
    moveImage.touch = yourTouchFunction
    prevIndex = newIndex
end

回答2:

You will probably need a keypair list to retrieve the index #, or make a multi dimension array (one to hold the index and one to hold the value.

http://www.dotnetperls.com/keyvaluepair

来源：https://stackoverflow.com/questions/20074349/how-to-assign-a-function-in-lua-for-a-randomly-generated-numbers