Change UIView alpha value
- by Ask
I'm trying to create an UIView and change its alpha property to simulate backlight change.
Here is my code
if (TransparentView == nil) {
TransparentView = [[UIView alloc] initWithFrame:self.view.bounds];
TransparentView.backgroundColor = [UIColor whiteColor];
self.view = TransparentView;
}
start=start+appDelegate.OnOffTime;
TransparentView.alpha = 0.2;
float step = 1.0 / ( appDelegate.OnOffTime * 100);
for (float f = 0; f < 1; f=f+step) {
TransparentView.alpha = (CGFloat)(1 - f);
[NSThread sleepForTimeInterval:0.01];
}
Both TransparentView.alpha = 0.2 and TransparentView.alpha = (CGFloat)(1 - f) do change TransparentView.alpha, but only TransparentView.alpha = 0.2 changes real device "brightness'.
What am I doing wrong?
