iPhone を回転させた時に検知する方法

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)FromInterfaceOrientation {
  if(FromInterfaceOrientation == UIInterfaceOrientationPortrait){
  // 横向き
  } else {
  // 縦向き
  }

}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
  return YES;
}