objective c - iOS 8 Auto Layout issue -

objective c - iOS 8 Auto Layout issue -

i have annoying problem auto layout occurs in ios 8, while same setup works fine in ios 7.

i've simplified , isolated problematic situation, , here how should work - , how does work in ios 7:

the feature consists of 1 container view (blue), , 3 sub views:

a label an image view (with sliced, scaled image) a button

i've added slider controls width of container view amending width constraint of container.

the auto layout constraints anchors label left-hand-side, button right-hand-side, , image view anchored both sides without having width constraint.

in ios 8, exact same setup looks this:

notice how image view (the black line) appears anchored offset outside right of container view.

i've tried , can't figure out why behaves differently in ios 8. i've removed , replaced constraints multiple times still same result.

these constraints set on each of sub views, respectivly:

and these constraints container view:

the width constraint of container view manipulated slider this:

- (ibaction)handlesliderchange:(id)sender { self.buttonwidth.constant = self.slider.value * 1024.0; [self.containerview setneedslayout]; [self.containerview setneedsupdateconstraints]; [self.containerview layoutifneeded]; [self.view setneedslayout]; [self.view setneedsupdateconstraints]; [self.view layoutifneeded]; }

others have had problems auto layout in ios 8 seems have been able solve similar issues calling setneedslayout , / or setneedsupdateconstraints directly on containing view, why i'm beingness explicit in calling on both containing view , root view. i've tried combinations of above, nil seems create difference.

i'm starting lose hope of finding solution, perhaps here has dealt similar situation , bring clarity issue?

edit: should add together i've tried set constraints image view label , button opposed edges of containing view same result.

edit 2: here's test project i've been using when trying isolate issue: download

it's not problem of auto layout, must bug in ios 8 handling sliced image assets.

with sample project:

uiimage *img = [uiimage imagenamed:@"pointer-dark-left"]; nslog(@"alignmentrect: %@", nsstringfromuiedgeinsets(img.alignmentrectinsets)); nslog(@"capinsets: %@", nsstringfromuiedgeinsets(img.capinsets));

this code prints

// ios 7 alignmentrect: {0, 0, 0, 0} capinsets: {0, 5.5, 0, 134} // ios 8 alignmentrect: {0, 0, 0, 65.5} capinsets: {0, 5.5, 0, 134}

alignmentrectinsets.right 65.5!

as documented, autolayout works alignment rectangles, , uiimageview uses images alignmentrectinsets. so, self.line has 65.5pt right width.

of course, didn't set alignment insets in xcassets editor, believe it's bug.

here ugly, working, workaround :(

- (void)viewdidload { [super viewdidload]; self.line.image = [self.line.image imagewithalignmentrectinsets:uiedgeinsetszero]; }

ios objective-c ios7 ios8 autolayout