弹窗队列：连续提示排队逐个展示

-- 错误：请求直接弹，叠屏互相遮挡
function showDialogNow(d)
    spawnDialog(d)
end

local queue, showing = {}, false
local function pushDialog(d)
    queue[#queue + 1] = d
    if not showing then
        showNext()
    end
end
local function showNext()
    local d = table.remove(queue, 1)
    if d == nil then
        showing = false
        return
    end
    showing = true
    showDialog(d, showNext)
end