issue about willAnimateRotate and didRotateFrom when doing an rotation - iphone

Question

What I am having so far is
-(void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
NSLog(#"willAnimateRotationToInterfaceOrientation");
if(toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown) {
NSLog(#"PortraitUpsideDown");
// Do method A
} else {
[[self.view subviews] makeObjectsPerformSelector:#selector(removeFromSuperview)];
// Do method B
}
}
and
-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
NSLog(#"didRotateFromInterfaceOrientation");
if( fromInterfaceOrientation == UIInterfaceOrientationPortrait || fromInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown){
NSLog(#"OrientationPortrait or PortraitUpsideDown");
[[self.view subviews] makeObjectsPerformSelector:#selector(removeFromSuperview)];
// Do method B
} else {
NSLog(#"From else");
[[self.view subviews] makeObjectsPerformSelector:#selector(removeFromSuperview)];
// Do method A
}
}
My logic is after hitting the RUN from xcode, willAnimateRotationToInterfaceOrientation: is going to be called because I set Supported Device Orientation to be UpsideDown from Summary of MyApp.xcodeproj. Moreover, I also think that didRotateFromInterfaceOrientation: should not be called because we have just started the app yet. It means there are no previous states at all.
Unfortunately, this is what I got after doing the debugger
2012-02-11 12:04:08.776 MyApp[7505:10703] willAnimateRotationToInterfaceOrientation :
2012-02-11 12:04:08.776 MyApp[7505:10703] PortraitUpsideDown
2012-02-11 12:04:08.778 MyApp[7505:10703] didRotateFromInterfaceOrientation :
2012-02-11 12:04:08.779 MyApp[7505:10703] OrientationPortrait or
PortraitUpsideDown
I am getting lost now. Does anyone have any ideas about the issue, please help. Thanks.

Answer 1

I have had some issues with rotation, similar to yours. The short version is that the will and did methods are not 100% reliable. You should try rapidly rotating back and forth and see what happens. It could be because I am pretty new, or it could be an actual bug. What I did was, in didRotateFromInterfaceOrientation:, check the current orientation and act accordingly:
if (UIInterfaceOrientationIsPortrait(self.interfaceOrientation) {
// do your portrait stuff
} else {
// do your landscape stuff
}
Before I found the UIInterfaceOrientationIsPortait test I was actually checking the frame to see if self.view.frame.size.width > self.view.frame.size.height, and that is also reliable but kind of ugly.
Either way is reliable. I have a couple apps in the store, QPalettes and QColor, that do rotation on a bunch of user-created onscreen elements. What I had to do is store the dimensions, and after didRotateFromInterfaceOrientation I check the new dimensions and if they are different, re-draw everything onscreen. Contact me if you'd like a promo code to check out the rotation in either app (they rotate the same - QColor is more complex since it also draws intersections).
Enjoy,
Damien