Reacting to a single touch only?

Questions
1

I have a sliding button class in which I’m using for my game, and you slide one of the four button to the center to choose something, but unfortunately there is a cheat as you can slide several buttons and if you are precise trigger two or more of the buttons and calling the functions associated with them eventually giving the awnser. Is there a way to set it so if you touch the screen once it will only react to that touch and no others?

2

Track the touches in a table, and only move the slider when it is touched by the touch associated with it.

Something like this code

function setup()
    touches = {}
end

function touched(t)
    -- sliders
    for i, slider in pairs(sliders) do
        if slider.touchId = nil and touches[t.id] == nil then 
            slider.touchId = t.id
        end
        if slider.touchId == t.id then
            -- normal slider touchy stuff
            
            if t.state == ENDED then
                slider.touchId = nil
            end
        end
    end

    -- Track touches
    if t.state == BEGAN or t.state == MOVING then
        touches[t.id] = t
    elseif t.state == ENDED then
        touches[t.id] = nil
    end
end

I think this should work.

3

@Mr_Ninja - why not set a global variable when a button is touched (eg put the button name or number in the variable), and clear it when the touch stops.

But when any button is touched, first check if the variable already has a value (ie set by another button). If so, ignore the touch. This way, only one button can ever “own” a touch.