I'm working on a layout that has a UIScrollView, and what I want to do is have a label pinned to the top of the scrollable area, and a button pinned to the bottom, with a minimum amount of space between the two.
The idea is that if the label grows in height the button will be pushed downwards so that the user has to scroll down to get to it. However, if the label is short, the space between it and the button should grow so that the button stays at the bottom of the scrollable area.
Below is a rough mockup of what I mean:
NOTE: The second shot is after scrolling all the way to the bottom of the UIScrollView, I want the button to be hidden when scrolled to the top; i.e- simply placing the button below the scroll view is not an option.
You can achieve the desired result with autolayout only, without having to change constraints via code. The steps are as follows:
1) Create your scrollview and pin it to all sides:
2) Add a view, which will act as content view, to the scrollview and pin it as well:
3) Your label and button will be added to this contentView, but before we can do this, we must add 2 additional constraints to the contentView. Create constraints for the width and height of the contentView to be equal as the SafeArea. You should set the priority of the equal heights constraint to low (250):
4) Add your label and button inside the contentView. The label pinned to the top and the button pinned to the bottom;
5) Lastly, add a vertical spacing constraint between the label and the button. Set the desired minimum amount of space between the button and the label as this constraint's constant, for instance 8, and set the relation to be Greater Than or Equal:
With this, if the label grows in height, the button will be pushed downwards so that the user has to scroll down to get to it.
Related
My storyboard layout is simple as shown in the attached image. I am assuming that the body text could span from a single line to multiple lines. Considering the case of multiple lines, I expect the content to scroll so that the button can be clickable. However, with the constraints I have set, the scroll view does not scroll. What constraints should I change in order to get the desired effect? Thank you.
The key to using UIScrollView: You must have a "chain" of constraints to allow auto-layout to determine the .contentSize of the scroll view.
Step-by-step (I like to set background colors during layout, to make it easy to see the bounds / frames of the elements)...
Add a UIScrollView (Cantaloupe color) to your view controller, and constrain it by 20-pts all the way around (just so we can see where it is):
Add a UIView as your ContentView (Strawberry color) as a subview of the scroll view. Give it equal Height and Width constraints to the scroll view, and top / leading / trailing / bottom constraints all set to 0:
Add your Title UILabel (Yellow background). Constrain it Top: 30 / Leading: 50 / Trailing: 50. Add your Body UILabel (Yellow background). Constrain its Top to the Title label's Bottom (I used 200), and Leading: 10 / Trailing: 10. Add your UIButton (Light Gray background). Constrain its Top to the Body label's Bottom (I used 50), and Leading: 50 / Trailing: 50:
So far, nothing special, and you won't get any scrolling...
Next, add another Bottom constraint of 0 to the ContentView, and change the first Bottom constraint to be >= 0 and set the Priority of the new Bottom constraint to 250:
This will (after a couple more steps) allow ContentView to expand / collapse based on its content, as well as control the .contentSize of the scroll view.
The next step is to tell the Button to determine the Height of the ContentView - so add a Bottom constraint of 30 to the button (which will be equal to the Top: 30 we gave to the title label):
Of course, that's not quite what we want. It stretches the height of the button because we set a height constraint on the ContentView. So... delete the height constraint from the ContentView:
The result is that the ContentView height will shrink to fit 30-pts below the bottom of the button.
If you add some more text to the Body label (assuming it is set to Number of Lines; 0), you will see the Body label expand and "push down" the button, which in turn "pushes down" the bottom of ContentView:
If you add enough text to Body to push the button below the bottom of the scroll view - either in IB or via code - it will now scroll vertically.
Hope that's clear... please ask if you have any questions.
In order to get your constraints proper for scroll view there are certain way you have to follow.please find below steps.
1.Add scroll view to super view.After adding scroll view add subview to scroll view as shown in the image.
This view will have same x,y co ordinate as well as same height and width as of scroll view.
Please refer below image to understand hierarchy.
You will find the red warning because we have not yet added any constraints.
Now its time to apply some constraints.
Refer image bellow and add top, bottom, leading and trailing to scroll view.
Now add same top, bottom, leading and trailing to scroll view’s child view. Refer below image.
Now is a real trick.Hold both scroll and view in one and give both of them equal width,equal height constraints as shown in below image.
Your constraints are almost set.now depending upon your contains stretch the view.
When you increase the view’s height after that click on update constraints.
The last thing you need to do is change scroll view’s bottom constraints value.It will be some negative value.Replace it with 0.follow below screenshot
Please update if it works
I am trying to layout my detail screen in IB with a tab bar and nav bar. However, there are three issues with the display when the simulator runs:
There is a gap at the top of the screen,
The dynamic label content extends past their container views at the bottom
The scrollbar doesn't reach to the bottom of the content.
Screenshot of simulator displaying the issues described
My question is how should I set my constraints so that the above issues are resolved?
I have a lot of constraints and I'm not sure where I'm going wrong or what would be the best way to present the steps I've taken so far. But here is a screenshot of my constraints and here is a summary of the constraints/steps I've taken so far:
Main view contains just one child: The Scroll View. Scroll view is pinned to top, leading, trailing of main view and bottom is pinned to the Bottom Layout Guide.top,
Scroll view has just 1 child subview ("Content View"). Content View is pinned to top + 64, leading, trailing, bottoms to Super View, and it has equal heights and widths to the Main view.
The content view has an image, Recipe Title subview, and Shadow Background subview. The Shadow Background subview contains another subview with some labels of dynamic height. I have constraints to pin the leading and trailing sides of these containers to the superview. And I have top, bottom, leading, trailing constraints to pin these subviews to the superview and/or eachother so that there is a chain from top to bottom.
The Shadow Background View contains the labels of dynamic height. The labels also have pin constraints of top, leading, trailing and bottom with the exception of the last label which does not have the bottom constraint.
I do not have any code that updates the layout-- everything so far is in the IB.
Any help is GREATLY appreciated!
Hallelujah! After spending a full frustrating week, I've finally found the magical formula in IB for laying out a scroll view + navbar + tab bar + dynamic label height.
My original problems were caused by the following mistakes:
Adjust Scroll View Insets should have been set to false
Content View Top and Bottom pins were incorrect
Missing some heights on some of the subviews
Last subview wasn't pinned correctly on the bottom
Maybe not all these steps are required and maybe this isn't the most perfect solution, but this is what worked for me. Here is a diagram of the solution for those that prefer pictures.
Main View -> Attributes Inspector -> Uncheck the Adjust Scroll View Insets checkbox.
Add Scroll View. This is the only child of the Main View. Pin Top, Leading, Trailing Space to the Main View. Pin the Bottom to the Bottom Layout Guide.
Add one subview (name it "Content View"). This is the only child of the Scroll View. Pin Top, Leading, Trailing Space to Scroll View. Pin Bottom to Scroll view with a constant of -49 to account for the tab bar. Also set its Height and Width to be equal to the Main View.
Add a child subview to the Content View. Top is pinned to Superview with a constant of 62 to account for the Nav Bar. Leading and Trailing is pinned to the Superview. The view also needs a Height-- give it either a fixed value or a minimum value if it is dynamic content (ex: Height >- 20). You may also need to give the Height constraints a lower priority such as 250.
Continue adding sibling subviews as needed. Pin the tops to the previous sibling subview. Pin the Leading and Trailing to the Superview. The last sibling subview should be pinned to the Superview. Each subview needs a height. There needs to be one continuous chain of constraints (Top & Bottom pins, Height) from the top subview through to the bottom in order to avoid that "Scroll View has ambiguous scrollable content height" warning and have the scroll work correctly.
Do a happy dance.
Hope this helps someone else.
Make the content view's top constraint have a constant of 0, not 64. For the label extending beyond the bottom of the container view, you'll have to post more information about the layout for us to help.
I've been trying to create a UIScrollView for user registry but with no success. I'm using auto layout and all of the fields that go inside the scroll view are static. Because of the usual ambiguous height issue, I've added a UIView inside the scroll view, set the constraints to the margins of the scroll view and centered aligned it. After that I added all of the fields inside that Content View, in the storyboard.
The content fields have their constraints setup as you would expect, but when I get to the lowest field and set the bottom constraint to the bottom of the Content View then everything breaks.
I'm asked by Xcode to set the priority of some views, and when I do as is says, the Content View size stays the same and the views are shrunken.
I tried not to put the last bottom constraint and resize the Content View by code but the height is not resized as is should.
I'm looking for a good solution to do this in storyboards and auto layout.
Update: I added a bottom constraint with a low priority, but the content scroll view is not expanding to show all of the fields.
Add&Set ScrollView(UIScrollView)
Add&Set ContentView(UIView) with subviews
! Set ContentView Width equal to View Width
Set all subviews constraints
View1 should be tied to the top of the ContentView
View4 should be tied to the bottom of the ContentView
All SubView (View1, View2, View3, View4 ...) must have a height and distance between each other
P.s. In your case, if iOS > 9.0 you can replace ContentView with UIStackView
You are using auto layout so the size of the content view is determined by constraints. Follow the below steps to provide proper constraints:
Drag the Scroll View inside main view and provide constraints Top, Bottom, Leading and Trailing in align with Super View (Main View) as
per screenshot.
Take View which will contain your content and drag inside Scroll View. and provide the constraints Center X, Center Y, Top, Bottom,
Leading and Trailing in align with Scroll View as per screenshot
Put all the element inside content view which is a subview of scroll view and provide Top constraint relative to the element above
it, to make equal space between the elements (eg. label, button etc.)
(Make sure you provide required constraint for X-position)
Last element is "Register Account" button make sure you provide the Top Constraint relative to country and Bottom constraint relative to
superview (content view) and change the priority for Top or Bottom
constraint as per screenshot, otherwise it gives error.
I have a weird behavior when I use scrollView.
As you can see in the picture bellow the button called "Back" has a bottom space constraint with value 0. But we can see is not even near to the bottom of the scroll view.
I already set the scrollview to have equals width and height of the superView and top,bottom,trailing and leading space with 0 value.
How can I fix this? I want the Back button still inside of the scrollview and put it at the bottom of the view.
Update
I have the code here https://github.com/rchampa/NDParallaxIntroView and the xib is called PageB.xib
Ricardo: you've added two constraint regarding manage y position of Validate Code button where your top constraint stop to move Validate Code button towards the bottom. So please remove top constraint of Validate Code only add bottom constraint.
you need to manage all constraint like your scrollview content view height will be equal to height. Please increase some top constraint from top.
So, if I understand correctly, the problem you are running into is that your back button is unable to be positioned based on the bottom of the scroll view.
A scroll has two sets of constraints in a storyboard, one that defines the size of the scroll view, and the other that defines the content size. The top, left, bottom, right to superview constraints on the scroll view will define the size.
The part that is causing your problem is that the content size is defined by the subviews inside the scroll view. So the button cannot be placed relative to the bottom of the scroll view since the scroll view doesn't know how large its content size is. All of the subviews of a scroll view must be placed in relation to each other.
So, create constraints for your logo, text fields, and all the buttons in relation to each other. Then create constraints from the outer most subviews to the scroll view.
In your example, you would constraints from the logo to the text field, 1st text field to 2nd text field, then 2nd text flied to the label, label to the "Send email..." button, and finally "Send email..." to the "Validate Code". For the "Back" button, it would need a left align with the text fields and then a center align with the "Validate Code" button. Create a top constraint from the logo to the scroll view. Then have leading and trailing constraints from one of the text fields to the scroll view. Finally, create a bottom constraint from either the "Back" or "Validate Code" buttons to the scroll view. You will also need some alignment constraints (logo center to the text field is an example of one). After that is all setup, your view will be fully defined for the content size of the scroll view.
If I understand you, my new question is: how can I make the subviews
make the height of scroll fit 100% screen device height? Is there a
way to define weights like Android? I don't know how achieve this
since the canvas is 600*600 which is different to every device.
Response would be too long for a comment:
So you wouldn't use a scroll view for that. A scroll view is specifically for containing content that will not fit on the screen (so the user can scroll to reach the new content).
The simplest solution is to add a regular view that has TopLeftBottomRight 0 distance constraints (so it is the max height and width of the screen) and setup the view like you have here to position the bottom in the bottom left all the time.
There is also a weight system, I can explain that if you want, but it wouldn't be required thus far.
I feel like your next response will be something like "what if I want it to scroll when its too small for the current screen?". The only way I know of doing that in encapsulating all your interface into a single UIView, and changing its sized in the viewDidLoad/viewDidAppear based on the size of the scroll view. Something like this:
func viewDidLoad() {
super.viewDidLoad()
containerViewHeightConstraint.constant = scrollView.frame.size.height
containerViewWidthConstraint.constant = scrollView.frame.size.width
}
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.