On 3/16/13 6:59 PM, "Kyle Sluder" <k...@ksluder.com> wrote:
>On Sat, Mar 16, 2013, at 05:38 PM, Chuck Soper wrote: >> I thought I'd create a new thread because I'm not sure I need to take >> that >> general approach for my specific case. My user interface works fine. The >> problem is that my documentView is ambiguous, but I think I can ignore >> that fact for my particular case. Here are the details: >> >> My documentView is a custom NSView subclass. >> >> From awakeFromNib in my documentView, I call: >> [self setTranslatesAutoresizingMaskIntoConstraints:NO]; > >This is the root of your problem. If you watch my auto layout talk, >which I gave before devising the solution I presented in the other >thread, I discuss how our then-current approach used this strategy and >noted the persistent layout ambiguity it caused. Is persistent layout ambiguity (for the documentView only) necessarily a problem? My UI works fine. I don't see how having the documentView ambiguous is causing a problem. I'll review your previous email and try to listen to your auto layout talk. Previously, I didn't call setTranslatesAutoresizingMaskIntoConstraints: on my documentView. I just added a subview to documentView and called setFrameSize: on the documentView. This worked great until I needed to change the width of the documentView by dragging the mouse. I'm starting to seriously regret trying to use auto layout with NSScrollView. I already have a quite a bit of of code that uses auto layout within the subviews of my documentView. >> >> >> I override updateConstraints in my documentView, and set up the >>following >> constraints (built in a for loop for 1 to N subviews): >> @"H:|[subview1][subview2][subview3]|" >> >> >> Each subview has an "NSLayoutConstraint * widthConstraint;" ivar that >> holds the absolute width. Visually, it looks like this: >> @"H:[subview(==120)]" > >You have now fixed the width of your documentView at (120 * N) points >wide. Yes, that's correct. So, the documentView is 360 points wide for this example. > >> >> >> I also added some minimum width and height constraints that look like >> this: >> @"H:[subview(>=80)]" and @"V:[subview(>=70)]" > >The horizontal constraint is unnecessary; the views are already at a >fixed width. Thanks. Good point. >> >> >> To pin the height of the documentView to its NSScrollView, I use the >> following constraint: >> NSDictionary * scrollViewsDict = >> NSDictionaryOfVariableBindings(documentView); >> >> [scrollView addConstraints: [NSLayoutConstraint >> constraintsWithVisualFormat: >> @"V:|[documentView]|" options: 0 metrics: nil views: >> scrollViewsDict]]; > >You have not shown any other vertical constraints for your subviews. If >all you have are the ">= 70" constraints, there are infinitely many >solutions to your document view height. That would be the source of your >ambiguity. I neglected to mentioned that in my documentView's updateConstraints method that I add @"V:|[subview(>=70)]|" to self for each subview. I thought the source of the ambiguity was related to not setting width constraint for the documentView. I do set each subview with @"H:[subview(==120)]" and specify the documentView layout with @"H:|[subview1][subview2][subview3]|" but I'm not sure that's enough. >> >> Actions and behavior: >> >> - Resizing the window changes the height of the documentView but not the >> width. >> - The width of each subview can be changed by adjusting the constraint >> constant, like this: subview1.widthConstraint.constant = 220.0; > >If you're manually updating the constants of these constraints, you >either need to clamp the value at a minimum of 80, or you need to make >the ">= 80" constraints a higher priority than the "==120" constraints. >Otherwise the first time you make the equality constraints' constants >less than 80, you will get an unsatisfiable constraints exception, and >AppKit will break one of your constraints. > >--Kyle Sluder Thanks for mentioning that. I actually check for the minimum width of 80 before setting subview.widthConstraint.constant when dragging the mouse. I added that check when I got an unsatisfiable constraints exception. You're correct. The the ">= 80" constraints may not be needed. Chuck _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
