wanted to implement brightness bar in ipad app

hey guys, i am working on a ebook reader and in its course i wanted to allow the reader to reduce/increase the brightness accordingly. what i tried is ,placed a UISlider and gave开发者_StackOverflow中文版 the values as 0 and 1 for min and max respectively. I placed a imageView on the main view and aplied alpha component to the uiview which responds to the slider accordingly. i succeeded but i know that it doesn't save the battery life of the ipad.

are there any predefined methods or framework which enables us to alter the brightness of the device.

thank you in advance

There is a private api call GSEventSetBacklightLevel(float). But if you are planning to submit this to the app store it will get rejected.

There is now of doing this via the public API, you could use, like you stated, a semi tranparent view with a black background over the window to make it look like you can control the brightness.,