Applying autoLayout constraints to multiple objects - ios

I am playing with autoLayout constraints in iOS
My use case is this way,
I will better explain with images
I am using a custom cell for UITableViewCell, through autolayout I have set constraints for text and divider line below and they obey autolayout constraints. Now you can see the yellow vertical strip on the left.
I have not set any constraints for it, so when the cell height is normal, it covers the whole cell, but when cell height increases, it doesnt increase and fill the whole cell. I am not able to make its height flexible w.r.t to cell.
I want to expand the yellow strip to cover the whole cell.
So how I can achieve this.

You can make height of yellow strip flexible by setting 2 constraints.
Set both top space and bottom space to container (cell's content view) to 0.
Ensure there is no constant height constraint for it.

You need to set constraints to the yellow view. By default it would apply its own constraints at runtime.
To the yellow view add TOP , BOTTOM , LEADING , and TRAILING constraint. DO NOT ADD A HEIGHT constraint.
Make sure the TOP and BOTTOM constraints of the yellow view are pinned to the cell's content view.
Let me know if it works.
Cheers

Related

Why is there a big margin in my scrollview when it's all set to 0

I have scrollview with a stackview with all my contents. I set all my margins to 8px but for some reason, there is a big space to the right. Even if I change the margin to 0px.
Am I doing something wrong?
Is it maybe better to make a tableview and make a cell out of my stackview? Seems very unnecessary to do this. But I cant figure this out.
When you define constraints inside a scrollview, the content doesn’t bind to the scrollview but to the content insets (margins). With this you can install content that is wider than the scrollview and be able to scroll horizontally.
What that means is the content of your scrollview can’t deduce its width just by sticking constraints to the sides, you have to explicitly set a width constraint on a child view.
In your example, it will use the smallest width it can, which looks to be the width of your three checkboxes.
To fix that, add a width constraint to any child view, like your first text field, or better, on your text edit because it takes the whole width.
In addition to this, you should add a CenterHorizontally constraint on your text edit too and make your left constraint on "Equal or Greater" or else your content will be aligned to the left.
Here is the official documentation on ScrollView to see this in more detail.
The content inside the scrollView must be the width of the device. The scrollView will not adjust to that width by itself. First try to set "equal widths" constraint of the scroll view to the view controller. If that doesn't work, keep reading.
For this StoryBoard, what you must do is put a UIView inside the scrollView.
The scrollView must be equal widths and equal heights of the viewController. Then the UIView must be equal widths of the scrollView, and then set its top and bottom anchor to the top and bottom anchor of the scrollview.
Copy all your subviews into this UIView.

How to use auto layout to resize views in a table view cell?

I have a cell in which I place four buttons and four labels. Each button gets assigned a picture with width 50 and height 50. Furthermore, all buttons have a corresponding label describing what they're intended for.
My objective is to have the buttons and labels resize to keep the buttons' and labels' aspect ration intact while the screen dimension changes on different devices. I have been playing with auto layout changing the hugging and compression to achieve this but haven't been successful yet. Any help would be much appreciated...
I think you should take a look at a UIStackView, because this seems exactly as a use case for stack. Just put each pair button/label in a stack, and then all four pairs into a horizontal stack, which you constraint to the cell itself. You should be able to handle all you need just by configuring the stack’s properties (axis, distribution, alignment, spacing).
Embed your button and label into a view. Set the width of this view equal widths to content view and change the multiplier value to 1:4. This will adjust the widths of the views according to superview. Also, set the top and bottom constraint to 0 for this view.
Provide center align y-axis constraint to button after setting the width and height constraint to 50. Set its top constraint to a value you deem fit.
Set labels's leading and trailing constraint to a value like 8. Choose center alignment for text. Also, provide top constraint to buttona nd bottom to its superview.
Copy the view and paste to create the three views and provide them equal widths constraint to the first view. Also, provide their leading, trailing, top and bottom constraints.
Here are a fast tutorial in how to achieve that:
1-
2- completion of the first Gif:
Note you can achieve the same output using a UIStackView

Swift - UIScrollView Scrolls Partially

My problem is slightly different from other's 'Swift UIScrollView' problems when using auto layout:
Problem:
Unlike others, when I run my app, it scrolls. My problem is that the scroll cuts off the bottom 20-30% of the content. I can pull to see the buttons did build and are down there, but when I let it go the scroll snaps back to a false bottom which cuts off my content!!! I've been trying, for days, to fix it to scroll the entire height but it continues to cut off!!
Description of app:
I used auto layout to layout 6 buttons and labels. Each button a rectangular image, with a label directly beneath it. (sorry, the site won't let me post pictures!)
I have my views arranged like this:
MainView > ScrollView > ContentView > Buttons & Labels
I have my contentView pinned to my ScrollView and my ScrollView pinned to my MainView. My buttons and labels all have constraints that are building correctly, to create a list that looks like:
Rectangular button
Label beneath it
Spacing
Rectangular button
Label beneath it
Spacing
Etc.
Can anyone tell me why I can't scroll the full length of the view?
Your description of how your items are constrained is vague, so I'm going to list all of the constraints you need to make this work. Then you can compare what you have to what you need and adjust accordingly.
Your ScrollView should be pinned on all 4 sides to the MainView. (This isn't absolutely necessary. You can constrain your ScrollView however you want, but make sure it can grow as the device and/or orientation changes).
Your ContentView should be pinned on all 4 sides to the ScrollView with offsets of 0.
Since you want your ScrollView to scroll vertically only, constrain the width of the ContentView to the width of the ScrollView using an Equal Widths constraint. To do this, in the Document Outline view, Control-drag from your ContentView to your ScrollView and select Equal Widths from the pop up.
The height of ContentView will be set by the sum total height of everything in it. In order for this to work, your topmost button needs to be pinned to the top of the ContentView, all of your buttons and labels should be pinned to their nearest neighbors, and the bottommost label should be pinned to the bottom of the ContentView. In addition, all of your buttons and labels should have constraints for their widths and heights. I would suggest setting an explicit width constraint and explicit height constraint for your buttons and centering them horizontally in the ContentView. For your labels, set an explicit height constraint and pin the left and right edges to the ContentView.
If you have these constraints and no other ones, your ContentView will be properly sized.
Using contentView, like you said, usually fixes the issue. So chances are you need to take a second look at your contraints. Maybe try this solution in a clean/new project to see that it works. (it does work). My guess would be that some of your constraints conflict each other.
Otherwise I think it would be a good idea to setContentSize of your scrollView in your viewDidLoad.
Another hack would be to place 2 UI objects with their alphas set to zero on the right top corner and left bottom corner. This would hint scrollView to set its contentSize.

Autolayout TableView Issue

I'm having a strange issue with my tableview, debugging the view hierarchy i'm getting this
I've tried a lot of constraints with no result, how should I setup my tableview to avoid that kind of misplacement ?
Edit
I've a custom cell with an image view, actually set just this 5 constraints
Top, bottom, leading and trailing values are 0
You just need to set Your UITableView constraint to Leading,Trailing, Top and Bottom. and also for your UIImageView set same constraint. so your imageview will show fit to cell as per table width. no need to set Align Center X constraint.

Adding UIButton to custom cell with auto layout

I am trying to add a button through IB in a custom cell at top right corner of the cell. I am using auto layout to position it correctly but in simulator I don't know why the button wont show up.
But if i create it programmatically then it shows up perfectly.
So my question is how can achieve it using IB and where i am doing it wrong.
I have added four constraints on my button leading and trailing space to superview and fix width and height.
Remove leading space constrain and add fix to top space constrain. I mean there will be total 4 constrains Fixed width, height and fixed trailing, top space to super view and it will work. If it is not working means you have not set your tableView constrains. For tableView fix it from top,bottom,left and right space from super view.

Resources