Screen Shift on UIInterfaceOrientationLandscapeRight

Question

I've got this application mainly displaying photographs.

The app was originally written for iOS 3.1 and upgraded to 4 before beeing published. It was not touched ever since. Now that the owner of the API appied some changes which ain't as compatible as they thought, I am forced to update the app. So I'll have to go for iPhone 5 and 6 and 6+ and iOS 7 and 8 updates in one go.

I observe this behaviour in the simulator of iphone 4, 5 and 6+ dimensions.

Portrait looks fine. Landscape left looks fine too. Landscape right is screwed up. Apparently it looks as if the whole screen were shifted to the left.

This is strange because I am not aware of anything that I would do different for landscape right or left. All I am doing is differnicating between any portrait and any landscape orientation.

It worked fine in the old version. But frankly I cannot reproduce this any more because I don't have access to the old xcode and sdk versions. But the app is in store for years and works fine on modern devices and modern OS versions.

A bit more background info, just in case it is of importance:

The app is based on a UITabBar, but it is not visible in this view.

The image is scrollable. It is placed on one view three times of the size of the screen with preceeding and succeeding image views place to the left and right respectively. This view with the three images is placed within a scroll view of the size of the screen or window respectively. This concept still works file, it is just shifted.

When I check the view item's frames in debugger or with NSLog, they all seem to be right, starting at (0.0/0.0) or respectively.

The view on the bottom with the four buttons that navigate to related functions and their view controllers, is re-alligned programmatically on each rotation, as well as the overlays with the textual information. All works as it should but it's shifted in this one orientation. Well, all views are layouted programmatically on each rotation.

There are no constraints defined. iOS6/7 deltas are all set to 0.

The app "wants fullscreen". By tapping on the image all UI items disappear and re-appear on the next tab. (Just by setting the .hidden attribute. Except for the navigation bar. Thats managed using setNavigationBarHidden:animated: with YES on animated) Works fine, even in the shifted view.

I am running out of ideas.

Answer 1

While I put all the details together for the question, eventually one idea came to my rescue.

The issue is related to hiding the tab bar. I could not use the regular way of hiding the tab bar because then it would not re-appear when navigating down to the functions that are associated with the buttons on the bottom overlay view.

Therefore I did some sort of hack. I did not hide it regularily but moved the tab bar out of the screen. AND: This was the only thing that I did differently for landscape right and landscape left. I just searched for the constant names and found it.

Apparently, manipulating the tab bar view had a flaw in older iOS versions. (Or in older SDK versions, I am still working on that important detail)

To overcome the flaw the tab bar view was modified this way for landscape right:

[self.tabBarController.view setFrame:CGRectMake(0-kTabBarHeight,0,width+kTabBarHeight,height)];

This does not seem to make sense but did help me out a lot on similar issues years ago when the app was written. Now, I changed this to:

[self.tabBarController.view setFrame:CGRectMake(0,0,width+kTabBarHeight,height)];

which is the same for landscape left too.

For the time beeing I separate between iOS versions >= 8.0 and smaller. But I'll double check that with older devices and may get back to this answer later.

I leave the question posted because I found the original "hack" here on SO too, so that I guess that others will have the same issues when updating to ios 8 or SDK 8 respectively.

Thanks for listening.