testbuttons.lua

local gui = require("gui")

function findMonitor()
    local available_perphs = peripheral.getNames()
    local selected_monitor = nil
    for index, perph_name in ipairs(available_perphs) do
        if string.find(perph_name, "monitor") then
            selected_monitor = perph_name
            break
        end
    end

    return peripheral.wrap(selected_monitor)
end

function main()

    local monitor = findMonitor()
    local buffer = createBuffer(monitor, "buffer", colors.black)

    local start_button = Button:new {
        name = "start_button",
        buffer = buffer,
        parent = buffer,
        x = 2,
        y = 2,
        text = "Start",
        horizontalAlignment = align.center,
        verticalAlignment = align.center,
        backgroundColor = colors.red,
        width = 5,
        height = 1,
        padding = 0,
        onClickName = "start_click",
        onClick = function(self)
            print("Clicked!")
            if (self.backgroundColor == colors.red) then
                self:setBackgroundColor(colors.green)
            else
                self:setBackgroundColor(colors.red)
            end
        end,
    }

    while true do
        buffer:draw()

        parallel.waitForAny(handleInputEvents())
    end
end

main()