Minecraft计时器脚本新增计时值存本地文件功能后失效，求排查解决

故障原因 #

新增代码存在多处语法、逻辑错误，同时原有代码也存在一处隐藏的时间计算错误，具体问题如下：

• 语法错误：io.open参数写法错误，local关键字不能放在函数参数内，字符串拼接缺少Lua的拼接运算符..，且没有将io.open的返回值赋值给file变量，直接调用file相关方法会报空值错误
• 变量错误：写入文件用的time变量不存在，原有计时器的当前计时值为os.time() - startTime
• 逻辑错误：读文件没有判断文件是否存在，首次进入没有存档文件的新世界时会直接报错
• 执行位置错误：新增代码如果直接放在update函数中，会导致state为0时反复读文件、state为1时每秒频繁写入文件，既浪费性能也容易触发文件IO冲突
• 原有代码隐藏错误：timeText函数中计算小时的逻辑写错，每次循环错误减去86400（一天的秒数）而非3600（一小时的秒数），会导致小时计算完全错误

修复方案 #

1. 先修复原有timeText函数的小时计算逻辑
2. 将文件读写逻辑迁移到状态切换的触发位置（按下按键切换状态时仅执行一次）
3. 修正文件读写的语法，增加文件存在性判断
4. 读取到存档计时值后，正确赋值给startTime变量恢复计时

修复后完整代码 #

name = "Timer"
description = "Just a normal Timer."
positionX = 0
positionY = 0
sizeX = 24
sizeY = 10
scale = 1

START_STOP_KEY = 0x55 --or 'U'
RESET_KEY = 0x4A --or 'J'
--[[
    if you wish to change the key you can take the key code from virtual key code table
]] -------------script-code-------------
previoustime = 0
state = 0
startTime = 0
stopTime = 0

ImportedLib = importLib("readfile.lua")

-- 封装存档读取函数
function loadTimer(worldName)
    local file = io.open(worldName..".txt", "r")
    if not file then return 0 end
    local savedTime = tonumber(file:read())
    file:close()
    return savedTime or 0
end

-- 封装存档写入函数
function saveTimer(worldName, time)
    local file = io.open(worldName..".txt", "w")
    if not file then return end
    file:write(tostring(time))
    file:close()
end

function keyboard(key, isDown)
    if (isDown == true) then
        if (key == RESET_KEY) then
            -- 重置时删除当前世界的存档
            local worldName = server.worldName()
            os.remove(worldName..".txt")
            state = 0
        elseif (key == START_STOP_KEY) then
            if (state == 0) then
                state = 1
                -- 开始计时前读取存档
                local worldName = server.worldName()
                local savedTime = loadTimer(worldName)
                startTime = os.time() - savedTime
            elseif (state == 1) then
                state = 2
                stopTime = os.time()
                -- 暂停时写入存档
                local worldName = server.worldName()
                saveTimer(worldName, stopTime - startTime)
            elseif (state == 2) then
                state = 1
                startTime = startTime + os.time() - stopTime
            end
        end
    end
end

TimerText = "00:00"
TextColor = {r = 30, g = 255, b = 30, a = 255}
function doubleDigit(number)
    if (number < 10) then
        return "0" .. math.floor(number)
    else
        return math.floor(number)
    end
end

function timeText(time)
    local result = ""
    local days = 0
    while (time > 86399) do
        days = days + 1
        time = time - 86400
    end

    local hours = 0
    -- 修复此处的减法错误，原代码错误减了86400
    while (time > 3599) do
        hours = hours + 1
        time = time - 3600
    end

    local minutes = 0
    while (time > 59) do
        minutes = minutes + 1
        time = time - 60
    end

    if (days == 0) then
        if (hours == 0) then
            return doubleDigit(minutes) .. ":" .. doubleDigit(time)
        else
            return math.floor(hours) .. " : " .. doubleDigit(minutes) .. ":" .. doubleDigit(time)
        end
    else
        return math.floor(days) ..
            " : " .. doubleDigit(hours) .. " : " .. doubleDigit(minutes) .. ":" .. doubleDigit(time)
    end
end

function update()
    if (state == 0) then
        TextColor = {r = 255, g = 0, b = 0, a = 255}
        TimerText = "00:00"
    elseif (state == 1) then
        TimerText = timeText(os.time() - startTime)
        TextColor = {r = 0, g = 255, b = 255, a = 255}
    elseif (state == 2) then
        TimerText = timeText(stopTime - startTime)
        TextColor = {r = 255, g = 255, b = 0, a = 255}
    end
end

function render()
    local font = gui.font()
    local tw = font.width(TimerText)

    gfx.color(0, 0, 0, 0)
    gfx.rect(0, 0, tw + 4, 10)

    gfx.color(TextColor.r, TextColor.g, TextColor.b, TextColor.a)
    gfx.text(2, 1, TimerText)
end

功能说明 #

• 切换到新世界首次按下U键开始计时时，自动读取对应世界的存档计时值，没有存档则从零开始
• 按下U键暂停计时时，自动将当前计时值保存到对应世界的txt文件中
• 按下J键重置计时时，自动删除当前世界的计时存档
• 修复了原有代码小时计算错误的问题

内容的提问来源于stack exchange，提问作者SebyGHG