调节iphone屏幕亮度
IOS5.0+中,UIScreen类多了一个属性brightness,可以调节main screen的屏幕亮度,值为0.0f-1.0f之间。点击这里查看UIScreen - brightness属性的解释. 这个做法应该是真正能省点的方法了,屏幕上覆盖黑层的做法,据说是不省电的。
brightness The brightness level of the screen. @property(nonatomic) CGFloat brightness Discussion This property is only supported on the main screen. The value of this property should be a number between 0.0 and 1.0, inclusive. Availability Available in iOS 5.0 and later. Declared In UIScreen.h