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Radar: UIScrollView Should Not Adjust Content Inset if it is Input View

May 08, 2013

While working on the demo app for my DTRichTextEditor I stumbled across a bug that exists since iOS 6. You’ll notice that only if you set an inputView on an editable UIView and have it become first Responder.

Filed as rdar://13836932 and on OpenRadar.

Update May 9th: Provided a Sample App, which is also available on GitHub.

Summary

You can set a view as inputView for a editable view to appear in place of a keyboard. If this inputView has a scroll view this will erroneously receive a setContentInset after the keyboard finished its incoming animation.

Steps to Reproduce

  • Create a UITableViewController
  • On a UIView that canBecomeFirstResponder set this VC’s view as inputView
  • have the UIView becomeFirstResponder

Expected Results

  • The UITableViewController’s tableView should not have a contentInset

Actual Results

  • Every UIScrollView receives a contentInset, even if it is itself the inputView that was showing “as keyboard”.

Regression

  • This automatic setting of contentInset started with iOS 6. It does not occur in iOS 5.

Notes

I believe that the notification that gets sent after the keyboard/inputView animated in should take into consideration that scroll views that are subviews of the showing inputView don’t get a contentInset set.

As a workaround I am subclassing UITableView and overriding setContentInset: to ignore the erroneous setting.

This is the call stack I get on this overwritten contentInset:

* thread #1: tid = 0x1c03, 0x0000f6ca RTEDemoApp`-[DTFormatTableView setContentInset:](self=0x099e5000, _cmd=0x09405f60, contentInset=(null)) + 58 at DTFormatTableView.m:16, stop reason = breakpoint 3.1
frame #0: 0x0000f6ca RTEDemoApp`-[DTFormatTableView setContentInset:](self=0x099e5000, _cmd=0x09405f60, contentInset=(null)) + 58 at DTFormatTableView.m:16
frame #1: 0x0373c1bd CoreFoundation`__invoking___ + 29
frame #2: 0x0373c0d6 CoreFoundation`-[NSInvocation invoke] + 342
frame #3: 0x016c7def Foundation`NSKVOForwardInvocation + 375
frame #4: 0x03737cf9 CoreFoundation`___forwarding___ + 905
frame #5: 0x0373794e CoreFoundation`_CF_forwarding_prep_0 + 14
frame #6: 0x00bc5029 UIKit`-[UIScrollView(UIScrollViewInternal) _adjustForAutomaticKeyboardInfo:animated:lastAdjustment:] + 377
frame #7: 0x00c14ddc UIKit`-[UITableView(UITableViewInternal) _adjustForAutomaticKeyboardInfo:animated:lastAdjustment:] + 73
frame #8: 0x00d87af9 UIKit`-[UITableViewController _adjustTableForKeyboardInfo:] + 201
frame #9: 0x00d86c27 UIKit`-[UITableViewControllerKeyboardSupport _keyboardDidChangeFrame:] + 131
frame #10: 0x016d44f9 Foundation`__57-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke_0 + 40
frame #11: 0x037a20c5 CoreFoundation`___CFXNotificationPost_block_invoke_0 + 85
frame #12: 0x036fcefa CoreFoundation`_CFXNotificationPost + 2122
frame #13: 0x01608bb2 Foundation`-[NSNotificationCenter postNotificationName:object:userInfo:] + 98
frame #14: 0x00f08a29 UIKit`-[UIInputViewTransition postNotificationsForTransitionEnd] + 682
frame #15: 0x00f01e5c UIKit`__53-[UIPeripheralHost(UIKitInternal) executeTransition:]_block_invoke_01079 + 203
frame #16: 0x00ba2df6 UIKit`-[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 223
frame #17: 0x00b95d66 UIKit`-[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 237
frame #18: 0x00b95f04 UIKit`-[UIViewAnimationState animationDidStop:finished:] + 68
frame #19: 0x006a57d8 QuartzCore`CA::Layer::run_animation_callbacks(void*) + 284
frame #20: 0x01ff0014 libdispatch.dylib`_dispatch_client_callout + 14
frame #21: 0x01fe07d5 libdispatch.dylib`_dispatch_main_queue_callback_4CF + 296
frame #22: 0x036eeaf5 CoreFoundation`__CFRunLoopRun + 1925
frame #23: 0x036edf44 CoreFoundation`CFRunLoopRunSpecific + 276
frame #24: 0x036ede1b CoreFoundation`CFRunLoopRunInMode + 123
frame #25: 0x02b757e3 GraphicsServices`GSEventRunModal + 88
frame #26: 0x02b75668 GraphicsServices`GSEventRun + 104
frame #27: 0x00b57ffc UIKit`UIApplicationMain + 1211
frame #28: 0x00001fec RTEDemoApp`main(argc=1, argv=0xbffff208) + 92 at main.m:15

At first glance I assume that you would want to modify _adjustForAutomaticKeyboardInfo:animated:lastAdjustment: to check if the UITableViewController’s view is part of the view hierarchy of the inputView that triggered the inputView frame size change notification.

Categories: Bug Reports

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