iOS获取屏幕亮度及设置lua

在iOS开发中，获取屏幕亮度通常需要使用UIKit框架下的UIScreen类。你可以通过以下步骤在Objective-C或Swift代码中获取当前的屏幕亮度：

**Objective-C:**

float screenBrightness;
[[UIScreen mainScreen] getBrightness:&screenBrightness];
NSLog(@"Screen brightness: %f", screenBrightness);

**Swift:**

let brightness = UIScreen.main.brightness
print("Screen brightness: \(brightness)")

设置屏幕亮度则可以使用`setBrightness(_: animated:)`方法：

let newBrightness = 0.5 // 设置新的亮度值，范围从0.0到1.0
UIScreen.main.setBrightness(newBrightness, animated: true)

如果你想在Lua脚本（通常用于Cocos2d-x游戏引擎）中操作iOS设备的屏幕亮度，你可能需要通过Objective-C或者Swift暴露一个API给Lua调用。例如，在Objective-C中，你可以这样做：

// LuaBridge示例（假设已经添加了LuaBridge库）
-(void)changeScreenBrightness:(lua_State*)L {
    float luaBrightness = lua_tonumber(L, 1); // 获取Lua传来的亮度值
    if (lua_isnumber(L, 1)) {
        UIScreen.main.brightness = luaBrightness;
    }
    else {
        lua_pushstring(L, "Invalid brightness value");
        lua_error(L);
    }
}
lua_register(L, "changeScreenBrightness", changeScreenBrightness);

然后在Lua脚本中调用这个函数：

local brightness = 0.7
changeScreenBrightness(brightness)