android 调节屏幕亮度

<span style="font-size:18px;"><strong>public void setBrightness(int level) { 
	ContentResolver cr = getContentResolver(); 
	Settings.System.putInt(cr, "screen_brightness", level); 
	Window window = getWindow(); 
	LayoutParams attributes = window.getAttributes(); 
	float flevel = level; 
	attributes.screenBrightness = flevel / 255; 
	getWindow().setAttributes(attributes); 
} </strong></span>