I had a view controller and some textviews and I am setting the textviews height dynamically using height constraint constant I set the the problem of inconsistency came at setting the height for two textviews...
One day I set its height for different devices(iPhone 4s,iPhone 5s,iphone 6s, iphone6s plus) and it was working fine for these devices but.. next day it wasn't working then I had to set the height constants again..
I am wondering how come this could happen ? why it worked previous day and why I had to change again ?
its very confusing this particular incident made me lose confidence on autolayout in xamarin.ios itself ?
Earlier some thing like this happened for one of the view's top constraint..
Please somebody tell me if there are any other things I have to be aware when it comes to autolayout in xamarin.ios ...
Please somebody clarify
Maybe first time you tested your app "AutoLayout" was enabled in storyboard, but at second time it was disabled.
Please check the link below and check the paragraph about enabling/disabling the "AutoLayout" property.
Related
I have a simple single screen app with two buttons that looks great on the story board on xcode. As soon as I run the app on my iphone 6s, it resizes the screen and the buttons at the bottom disappear. It looks like the resolution has changed and the app is not meant for an iphone 6s screen.
I have already tried the following without any success:
1) Enabled "Use Auto Layout" for my View controller in the File Inspector menu(under utilities)
2) Set the deployment target to "10.3", Devices to "iPhone" and checked "portrait, landscape left and landscape right" for Device orientation under the General Settings.
Is there any other setting that I might have missed to check that is causing this scaling? I am using xcode 8.3
Edit: I recieved some great feedback in the comments section, and learnt about adding constraints. I am here adding screenshots of what my app looks like before and after adding constraints:
Here is my xcode storyboard (what I am looking to get on my iPhone 6s)
And here is a screenshot of what I have on my phone (prior to constraining)
I have tried constraining the view like so with no luck (same output on the phone):
Is there a specific set of constraints that will do the job here?
Your screenshots show that you have not set your constraints. The last screenshot shows that you have set some constraints on the root view. Like mentioned by Martin you need to have constraints for each object.
To place the button correctly at the bottom of the view, you need to draw from your button to your view (holding the ctrl-key) and then select the bottom, leading and trailing constraints.
I suggest to make a beginner tutorial in Autolayout with InterfaceBuilder.
Thank you for your great responses. Turns out the solution was a little different than just experimenting with constraints. It took me about 3 hours to figure this out, and I wanted to share the simple solution here in case someone else goes through the same thing in the future.
The problem was in the General section of the settings. Your Launch Screen File must reflect the MainStoryboard like so:
My Launch Screen File option was previously set to nothing which caused the problem. As soon as I changed it to the MainStoryboard, things look just fine.
Hope this helps someone!
This has happened on a couple of apps I've been working on, and I believe it has something to do with Navigation bars or Tab bars. I'll work on another screen and be messing with the code and then I'll randomly scroll across the Storyboard and see that all the constraints have suddenly changed values and some items have expanded to 1000 x 1000.
Has anyone experienced this before, and know what is causing it? It's happened quite a few times to me now and it's obviously annoying to reset them each time.
Since you updated your Xcode to 8, you may need to update frames in the whole scene (once).
If you do that each time and it doesn't help, for me changing size of the storyboard helped. For example change from iPhone SE to iPhone 6 and vice-versa.
Now in Xcode 8.1 Beta version, there is a shortcut button for this.
Just select the problematic view's superview (containing mentioned constraints), and click this update frames button:
So I've been working on an XCode Project for a while, it's practically done but there's a problem I didn't realize until it was too late. I'm working without Size Classes but with Auto Layout. I have a background image in the back and some buttons and labels over it. When I was setting the constraints for everything it all seemed to be in its place and I tested it various times in the same device size (iphone 5s) with the simulator. Now I decided to test it with the iPhone 6, and everything is wrong and not in the place I want it to be. How do I make labels/text fields/buttons keep the same size in ratio to the device?? How could I adapt things proportionally?? Please help.
I was getting the same issue , But after some R&D found useful solution .
Have a look into given link :Set view controller in ratio for iPhone-6 and 6+
Its very easy process and working for me .
I'm sorry for the bad explanations but I've found the way to do it. Here's the video that explained me how use constraints based on proportions and not on pixels.
https://www.youtube.com/watch?v=Gl6DibzPYa4
(The first 5 minutes is basically it)
I'm using autolayout to correctly lay out some views inside a UICollectionViewCell. It works fine with iOS 8, but when I try to run it on iOS 7 or iOS 6, the cells appearance varies widely everytime they are laid out (sometimes I see small changes in size and positions - one or two pixels - and sometimes big changes, resulting in some pretty messed up cells).
I swear I tried hard to find anyone with the same problem, but I couldn't. I didn't find any answer that could help me solve or even get close to understanding the problem either.
I would appreciate any inputs on how to solve or even debug this better.
MORE INFO
I'm using Interface Builder to create the view and set up the constraints. The cell's view has a total of 17 subviews, including UIViews and their subviews, and they do have a great number of constraints.
I update a UIColletionView (which includes a table of my custom cells) everytime I press a button.
What I find outrageous here is that when I run the app, everytime I press the button, the cells' subviews change their positions and sizes. I never change any constraint or frame programatically.
Also, the behavior is worst on iOS6. The frames chage a lot more and autolayout runs really slow (it take 3-10 seconds to update the collection view on iPod Touch 5th Generation, even if it has only one cell).
Worst of all, if I keep updating the UICollectionView, sometimes XCode will complain of constraints not being simultaneously satisfied. But most of the time it works just fine.
I'm also running into crashes in some devices when removing some of my autolayout-enabled views from superview. I found this is a strange behavior of Autolayout engine, which could get to some bad calculations due to float errors. I'm wondering maybe this two problems are related.
As I couldn't find any help in the entire web after searching for almost an entire day, I'm starting to think this must be a stupid error with a stupid solution. I do hope so.
Thanks in advance!
SCREENSHOTS
I'm adding some screenshots to help you visualize the problem. To get those screenshots, I run the app on iPod Touch 5th generation with iOS 6. The behavior is different on iPhone 4 with iOS 7 (it behaves much better, but I still get the elements moving around some pixels).
Everytime I press the "Update" button, I remove the view which contains the UICollectionView from its superview (the entire screen) and add it again. I do not destroy this view, it is created only once. I thought that could be the origin of the problem (some autolayout calculation buffer holding values from previous layout), but destroying it didn't solve the problem (altough it did make the displacements less frequent and disturbing, but at the cost of performance).
This is the expected behavior. This is the view I get when the app open:
Misplaced views. This is the result of pressing the "Update" button for the first time:
Result after pressing the button a second time:
Result after pressing the button a third time:
If I keep pressing the button, I get layouts alternating between screenshots 3 and 4 (or at least they look pretty like the same).
I'M GIVING UP AUTOLAYOUT AND HERE IS WHY
Well, I'm really giving up using auto layout. I've spent almost a week learning to do a lot of thing with it (specially laying out and animating views). I thought it is a wonderful and powerful feature and I learned to love it. But then I needed to support iOS6 and iOS7.
I found it only works great on iOS8 (with any device, old or not). I don't know if I'm doing something really stupid, because I can't find any threads on the internet talking about three killing problems I've been facing.
I'll list them here just in case somebody come across this thread sometime in the future with the same problem or with a solution. They are listed ordered by the priority I gave to them to why I'm giving up autolayout.
1) Performance
Autolayout runs really slow on iOS6 and a little slow on iOS7 (compared to iOS8 - remember I'm developing with XCode 6.2 and iOS8.2 SDK). The same hardware with iOS8 runs the same code just fine.
To get to this conclusion, I ran my app in two iPod Touch 5, one with iOS6 and the other with iOS8. The difference in performance was pretty clear. Loading or dismissing a simple view (11 subviews) in iOS6 could take more than 5 seconds (on iOS 8, never took more than 1). On iPhone 4 with iOS7, the same code performed much better than in iOS6, but slower than in iOS8.
I'm sure it is an autolayout related problem because, using the same code, I disabled autolayout (and size classes) for some specific XIBs and they runned stupendously fast on iOS6, while the other views kept being slow (if you are going to try this, remember to delete the old app, clean the project and build it again, or it will still use autolayout).
2) Random crashes on specific devices with iOS6 or 7 when dismissing a view controller or removing a view from its superview
The problem is clearly stated here. It seems I'm bumping into the float error problem, because I can see some e-08 numbers on the crash log.
This is a serious problem for autolayout adoption. It's a random, unpredictable - but reproducible - crash. The same layout constraint can work in various devices, with different iOS versions. But it can also crash in some of them. Example: I had a view that worked fine on iPhone 4 (iOS7) and that crashed when dismissed on iPad Air (same iOS). The solution? Change the constraint's items relation from
x.width = y.widht*0.8 + 0
to
y.width = x.widht*1.25 + 0
which is equivalent matematically, but avoided the crash.
I searched a lot if anybody had a way to know when this crash could happen or how to tackle it down forever, so I could make my views without having to worry about testing them on every device, with every iOS version, to make sure it wouldn't crash. I couldn't find a away to fix it.
This crash doesn't seem to happen in iOS8.
PS: I tried removing the constraints from all my subviews before removing the view from superview, but then the crash occurred when removing one constraint. I couldn't find any good reason to why it was crashing when removed.
3) The problem I describe in the first part of this question
It's a third priority problem because I could solve this designing the cells without autolayout. This would be a minor problem if the rest of the app do not use cells, which is the case.
But it is still a problem I cannot understand nor solve with autolayout. When I remove autolayout, the cells are displayed just fine. And they do work fine on iOS8 and I double checked if I was using some specific iOS8 feature and I'm not.
BOTTOM LINE
I'm giving up autolayout while I have to support both iOS6 and 7 or until I can find a way to fix at least the first two problems I listed above.
I've tasted the power of Autolayout and I really like it, but I can't develop worrying about unpredictable crashes hidden on some mysterious dismiss in a specific hardware with a specific iOS version. Nor can I accept the poor performance of iOS6 (sometime soon we should drop support to iOS6, though, so this will be a lost problem).
My app is suddenly unable to correctly display UIDatePickers. I'm using storyboards. The Datepickers are set to just display the date. They are cutting off the month, and also not even showing the days. There's a big space in the middle. I have tried cleaning the project, resetting the simulator, checking localization settings, and checking to see if dynamic type size was set. I'm using Xcode 5.1.1 but the same thing happens in the beta of Xcode 6. Any suggestions would be appreciated.
Ok, I figured it out. This happened as a result of trying to use UIAppearance on a tableView background color. This has nothing to do with tableViews on the face of it, but Apple must be using a tableView privately for the PickerViews. So, my attempt to set a UIAppearance via a category on a tableView background color seems to be doing something unexpected. Lesson learned. Don't try to use UIAppearance where they are not officially supported.
I had this exact same issue, and it was related to duplicate constraints in my storyboard. I'd been implementing iPhone 6 widths and inadvertently ended up with both width = 320 and width >= 320. Removing that width = 320 fixed it instantly.