A lot has happened in iOS 6 and apple has a document which you may read it from here. The above document will guide you out regarding the changes that has happened in iOS technology.
Few of the changes i am mentioning it down so that you can read them as i feel that those are the important changes in iOS6.
· In iOS 5.1, the
UISplitViewControllerclass adopts the sliding presentation style when presenting the left view (previously seen only in Mail). This style is used when presentation is initiated either by the existing bar button item provided by the delegate methods or by a swipe gesture within the right view. No additional API adoption is required to obtain this behavior, and all existing APIs—including that of the
UIPopoverControllerinstance provided by the delegate—will continue to work as before. If the gesture would be insupportable in your app, setting the
presentsWithGestureproperty of your split view controller to
NOdisables the gesture. However, disabling the gesture is discouraged because its use preserves a consistent user experience across all apps.
· In iOS 6, changes have been introduced so that you no longer need to set a delegate and implement a method for single-finger and single-tap gesture recognizers. This makes them work well with the
· In iOS 6 and later, the
UIWebViewclass paints its contents asynchronously.
· Autorotation is changing in iOS 6. In iOS 6, the
UIViewControlleris deprecated. In its place, you should use the
· More responsibility is moving to the app and the app delegate. Now, iOS containers (such as
UINavigationController) do not consult their children to determine whether they should autorotate. By default, an app and a view controller’s supported interface orientations are set to
UIInterfaceOrientationMaskAllfor the iPad idiom and
UIInterfaceOrientationMaskAllButUpsideDownfor the iPhone idiom.
· A view controller’s supported interface orientations can change over time—even an app’s supported interface orientations can change over time. The system asks the top-most full-screen view controller (typically the root view controller) for its supported interface orientations whenever the device rotates or whenever a view controller is presented with the full-screen modal presentation style. Moreover, the supported orientations are retrieved only if this view controller returns
shouldAutorotatemethod. The system intersects the view controller’s supported orientations with the app’s supported orientations (as determined by the
Info.plistfile or the app delegate’s
application:supportedInterfaceOrientationsForWindow:method) to determine whether to rotate.
· The system determines whether an orientation is supported by intersecting the value returned by the app’s
supportedInterfaceOrientationsForWindow:method with the value returned by the
supportedInterfaceOrientationsmethod of the top-most full-screen controller.
setStatusBarOrientation:animated:method is not deprecated outright. It now works only if the
supportedInterfaceOrientationsmethod of the top-most full-screen view controller returns
0. This makes the caller responsible for ensuring that the status bar orientation is consistent.
· For compatibility, view controllers that still implement the
shouldAutorotateToInterfaceOrientation:method do not get the new autorotation behaviors. (In other words, they do not fall back to using the app, app delegate, or
Info.plistfile to determine the supported orientations.) Instead, the
shouldAutorotateToInterfaceOrientation:method is used to synthesize the information that would be returned by the
didRotateFromInterfaceOrientation:methods are no longer called on any view controller that makes a full-screen presentation over itself—for example,
· You should make sure that your apps are not using these methods to manage the layout of any subviews. Instead, they should use the view controller’s
viewWillLayoutSubviewsmethod and adjust the layout using the view’s bounds rectangle.
· In iOS 6, the
UIViewControllerare now deprecated. If you were using these methods to release data, use the
didReceiveMemoryWarningmethod instead. You can also use this method to release references to the view controller’s view if it is not being used. You would need to test that the view is not in a window before doing this.
· It is not supported to set values for the
shadowColorproperties of a
UILabelobject if its
attributedTextproperty contains a valid attributed string. Instead, use the
NSShadowAttributeNameattribute of the attributed string to set the shadow.
· Due to compatibility concerns, the
NSBaselineOffsetAttributeNameattribute is no longer supported in iOS 6.
NSTextAlignmentNaturalvalue is not supported. It will throw an exception when it is used with the
UILabelor is supplied as the alignment parameter to the
UIViewhas been deprecated. To achieve the same effect, use the
UIImageand display the image with a
UIImageeffectively resizes images by tiling. As a performance optimization, it uses stretching rather than tiling when the user would not be able to tell the difference, such as when a single column or row is being stretched. But in certain circumstances, the user might want to actually stretch some region of an image. In iOS 6, the
resizableImageWithCapInsets:resizingMode:method allows the caller to specify a tiling or stretching resizing mode.
UICollectionViewLayoutclass has changed:
· The class now supports the customization of the animations created during rotation. The names of methods for customizing insert and delete animations have also changed, so the same hooks can be used for rotations as well as for insertions and deletions.
· The class has changed some method names. Specifically, decoration views are no longer referred to by “reuse identifier” but rather by “element kind.” Apps that are using decoration views will need to modify their code and be rebuilt to accommodate this.
· The bottom edge of a
UILabelview is now different from its baseline.
Previously, Auto Layout was interpreting the bottom of a
UILabelto be the same as its baseline. While convenient in many cases, it caused problems if you wanted to place the top edge of one label against the bottom edge of another. In such a scenario, the bottom label would overlap the top one, and descenders from the top label could crash into ascenders from the bottom label. Now, Auto Layout interprets
UILayoutAttributeBottomas the bottom of the text box (presuming the label is not bigger than its intrinsic content size) and
UILayoutAttributeBaselineas the baseline of the text. If you have already created code for laying out labels according to the bottom or center point, your text will move around a little and you will need to adjust your constraints.
· Apps with table views in their nib or storyboard files, and that were built using previous versions of iOS 6 beta, will require a clean build with beta 3 and newer.
Landscape-only apps that invoke a portrait-only view controller (such as the Game Center login screen) will cause the app to crash.
1. Apps should provide the delegate method
application:supportedIntefaceOrientationsForWindowand ensure that portrait is one of the returned mask values.
2. When a
UIBNavigationControlleris involved, subclass the
· No privacy alerts are displayed in iOS Simulator for apps that access Photos, Contacts, Calendar, and Reminders.
· For this release, iOS Simulator does not support testing In-App Purchase. Please use a device to test your apps that use this feature.
· When attempting to play an MP3 sound in Simulator, you will hear a popping sound instead.
I hope that by reading this post you have some clearance on iOS6.