【界面UI】技能栏自定义换肤：皮肤资源与按钮态的界面方案

local SKINS = {
    classic = { normal = "res/skin/c_normal.png", press = "res/skin/c_press.png", disable = "res/skin/c_off.png" },
    flame = { normal = "res/skin/f_normal.png", press = "res/skin/f_press.png", disable = "res/skin/f_off.png" },
}
local function applySkin(widget, theme, state)
    local s = SKINS[theme] or SKINS.classic
    GUI:Button_loadTextures(widget, s.normal, s.press, s.disable)
end

local theme = "classic"
GUI:addOnClickEvent(fireBtn, function()
    applySkin(fireBtn, theme)
    castFire()
end)
local function restoreTheme()
    theme = loadLocal("skill_skin") or "classic"
    applySkin(fireBtn, theme)
end