UIScrollview content size when orientation changes

Question

I have a scrollview with pagination. In viewDidLoad i check if the current orientation is landscape then i set its contentsize's height 440

 if (UIDeviceOrientationIsPortrait([[UIDevice currentDevice] orientation])) 
    {
        [scroll      setContentSize:CGSizeMake(self.scroll.frame.size.width*numberOfPages,340)];


    }
    else if (UIDeviceOrientationIsLandscape([[UIDevice currentDevice] orientation]))

    {
        [scroll setFrame:CGRectMake(0,0,480,480)];
        [scroll setContentSize:CGSizeMake(self.scroll.frame.size.width*numberOfPages, 440)];


    }

everything works fine scrollview scrolls smoothy and there is no diagonal scrolling.

but when orientation changes,

i have to set scrollview's frame and contentsize again and i am setting it as follow

-(void)orientationChanged:(id)object
{
if(UIDeviceOrientationIsPortrait([[UIDevice currentDevice] orientation]))
{
    self.scroll.frame = [[UIScreen mainScreen]bounds];

    [scroll setContentSize:CGSizeMake(self.scroll.frame.size.width*numberOfPages, 340)];
}


else
{
 self.scroll.frame = CGRectMake(0,0,480,480);
        [scroll setContentSize:CGSizeMake(self.scroll.frame.size.width*numberOfPages, 600)];
}


}

i cant understand why i have to set content size's height upto 600 in landscape mode, and that too isnt enough. and it adds one more problem that scrollview starts scrolling diagonally which i dont want as it looks so weird. Can anyone help me understanding where and what i am missing?

i have set scrollview's autoresizing mask as

[scroll setAutoresizingMask:UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleRightMargin|UIViewAutoresizingFlexibleHeight];

but changing it doesnt help.

Answer 1

1. Don't use UIDeviceOrientation. Use UIInterfaceOrientation instead. DeviceOrientation has two extra options you don't need here. (UIDeviceOrientationFaceUp and UIDeviceOrientationFaceDown)

2. Return Yes from shouldAutorotateToInterfaceOrientation

3. Now willRotateToInterfaceOrientation: duration: will be called every time you rotate your device.

4. Implement this method like this.

   -(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
   {
   CGRect frame;
   int pageNumber = 2;
   int statusBarHeight = 20;
   
   if ((toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft) || (toInterfaceOrientation == UIInterfaceOrientationLandscapeRight)) {
       frame = CGRectMake(0, 0, 480, 320 - statusBarHeight);
   } else {
       frame = CGRectMake(0, 0, 320, 480 - statusBarHeight);
   }
   
   scrollView.frame = frame;
   scrollView.contentSize = CGSizeMake(frame.size.width * 2, frame.size.height);
   } 
   

   Let,

   pageNumber = 2

   statusBarHeight = 20