Autolayout issue

[serhatsezer]

I tried to use this library explained in the onboarding page but it gives me a auto-layout warning:

`[LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x608000285f00 V:|-(0)-[UICollectionView:0x7f803388e800] (active, names: '|':Parchment.PagingView:0x7f8032d46f50 )>",
"<NSLayoutConstraint:0x608000286090 UICollectionView:0x7f803388e800.height == 40 (active)>",
"<NSLayoutConstraint:0x608000285690 V:[UICollectionView:0x7f803388e800]-(0)-[UIView:0x7f8032d41970] (active)>",
"<NSLayoutConstraint:0x608000282440 V:[UIView:0x7f8032d41970]-(0)-| (active, names: '|':Parchment.PagingView:0x7f8032d46f50 )>",
"<NSLayoutConstraint:0x600000292ac0 'UIView-Encapsulated-Layout-Height' Parchment.PagingView:0x7f8032d46f50.height == 0 (active)>"
)

Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x608000285690 V:[UICollectionView:0x7f803388e800]-(0)-[UIView:0x7f8032d41970] (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.`

[rechsteiner]

Hi! I'm not able to reproduce the warning you're seeing. Could you provide a bit more details on your setup? Are you running one of the example targets? And which version of iOS and Parchment are you using?

[serhatsezer]

@rechsteiner Yeah sorry I couldn't give you more detail about the error. But I didn't do any customization or adjustment. I went through readme file. I tried to add both inside custom view and view controller's view but it still gave me the above layout error. I also gave title every controller, I looked all of the example projects. I tried to investigate the error but I couldn't do it because I have little time.

[rechsteiner]

Okay, no worries. Have you added any constraints to the PagingViewController so that it's attached to its parent view? I realize now that the README doesn't include anything about setting up the constraints, but if you look at the Example target I'm setting up the constraint using a convenience helper like this:

view.constrainToEdges(pagingViewController.view)

[serhatsezer]

@rechsteiner Yes I saw your extension but I already add PagingViewController view into my already-constrained view. You can see example below;

let pagerHolderView = UIView()
        view.addSubview(pagerHolderView)
        
        pagerHolderView.snp.makeConstraints { make in
            make.edges.equalTo(self.view).inset(UIEdgeInsetsMake(50, 0, 50, 0)) // 50 for tabbar offset.
        }

[rechsteiner]

Ah okay. Are you using the latest version of iOS and Parchment? Is there anything else you’re doing that might be relevant, like subclassing PagingViewController?

[rechsteiner]

Are you still having issues with this?

[mikehobi]

Back again.

I got the same auto-layout warning as @serhatsezer,

When I try to add the view.constrainToEdges(pagingViewController.view) bit, I get this:

[rechsteiner]

Oh, that's because constraintToEdges is not available as part of Parchment. It's only an extension that I made to use in the example targets. You can copy the extension from UIView+constraints.swift in the example target or setup the constraint manually with something like this:

pagingViewController.view.translatesAutoresizingMaskIntoConstraints = false
    
NSLayoutConstraint.activate([
      pagingViewController.view.topAnchor.constraint(equalTo: view.topAnchor),
      pagingViewController.view.bottomAnchor.constraint(equalTo: view.bottomAnchor),
      pagingViewController.view.leadingAnchor.constraint(equalTo: view.leadingAnchor),
      pagingViewController.view.trailingAnchor.constraint(equalTo: view.trailingAnchor),
])

[mikehobi]

Fixed my issue 👍 , you're the best.

[serhatsezer]

@rechsteiner Great. I think this library is pretty neat. Will you fix this framework itself as well? or We can make a pull request for it. People who want to use this library may not see this issue.

[rechsteiner]

Thanks! I still haven't been able to reproduce the issue you're seeing, but if you could provide some steps for reproducing it I can fix it right away. And feel free to open a pull-request if you already have a fix for it.

[rechsteiner]

@serhatsezer I think I managed to get this fixed now with #125. Can you check out the master branch and see if you're still seeing the layout warnings? 🙏

If you're using CocoaPods you can target the master branch like this:

pod 'Parchment', :git => 'https://github.com/rechsteiner/Parchment.git', :branch => 'master'

Or this if you're using Carthage:

github "rechsteiner/Parchment" "master"

[serhatsezer]

@rechsteiner Okay it is worked. But there is another problem which I face now. I implemented via pod file which you provided me. Menu items collapsed when I didn't give any title label for FixedPagingViewController. But when I rotate the device in landscape mode it works well. But when I change to top anchor constraint to deprecated one it's working well. I think we should implement this layout code inside FixedPagingViewController this way we can give appropriate layout constraints.

pagingViewController.view.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            pagingViewController.view.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor),
            pagingViewController.view.bottomAnchor.constraint(equalTo: bottomLayoutGuide.topAnchor),
            pagingViewController.view.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            pagingViewController.view.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            ])

My implementation;
https://gist.github.com/serhatsezer/6c53e558db0e8880e8594e5a8bf63b16

[rechsteiner]

Thanks for the detailed report! Looks like you found a bug that was introduced a while ago (#81). Should be fixed in #127! Releasing a new version now ✌️

[rechsteiner]

New version with both fixes is out now. Let me know if you find any other issues!

[serhatsezer]

@rechsteiner Great thanks. I'll use this framework for future projects. I'm also thinking to contribute to new features. Cheers!

[rechsteiner]

Awesome!