自动版式：NSInternalInconsistencyException与iOS11

Question

App getting crashed with the following logs(PFA) and Its only getting crash in iOS 11.

Fatal Exception: NSInternalInconsistencyException, Impossible to set up layout with view hierarchy unprepared for constraint.

__120-[UIView(UIConstraintBasedLayout) _layoutEngine_didAddLayoutConstraint:roundingAdjustment:mutuallyExclusiveConstraints:]_block_invoke_2

Update :-

Scenario:- I have a UIToolbar on the keyboard, The code for adding

The view hierarchy is not prepared for the constraint: NSLayoutConstraint:0x1c0295540 V:[UIToolbar:0x10219f550]-(0)-[_UIRemoteKeyboardPlaceholderV‌​iew:0x10219fab0] (inactive)

#pragma mark  KeyBoard Related Function
-(void)createInputAccessoryView:(NSInteger )tagNumber
{
    inputAccessoryView = [[UIToolbar alloc]init];
    [inputAccessoryView setBackgroundColor:kKYBOARDCOLOR];
    [inputAccessoryView sizeToFit];
    [inputAccessoryView setHidden:NO];

    //Use this to put space in between your toolbox buttons

    UIBarButtonItem *barSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace
                                                                              target:nil
                                                                              action:nil];

    UIBarButtonItem *barBtnDone = [[UIBarButtonItem alloc] initWithTitle:@"Done"
                                                                   style:UIBarButtonItemStyleDone
                                                                  target:self action:@selector(actnResignKeyboard)];
    NSArray *barItems;
    barItems = [NSArray arrayWithObjects:barSpace,barBtnDone, nil];
    [inputAccessoryView setItems:barItems animated:YES];

}

Appearing and disappearing keyboard causes crash but when I remove UIToolbar, then every thing working fine.

Note :- This code is working fine prior to iOS 11.

Answer 1

Did you try printing the stacktrace to know which layout or view hierarchy causes this? Also try adding the views to the superview first and then apply the constraints