I'm trying to make a view scrollable in my app.
O follow exactly the steps in tutorial https://www.youtube.com/watch?v=UnQsFlMGDsI .
The main steps I did were:
Add a UIscrollView
Add a view into UIscrollView (Content View)
Create the margin constraints with value 0 (top, left, right and botton) for UIScrollView
Create the margin constraints with value 0 (top, left, right and botton) for Content view
Create 2 constraints of "equal width" and "equal height" between ContentView and main view
... (Add some text fields)
When I run the app, the scrollView doesn't work
I really can't make it work. I tried many ways to apply a UIScrollView and didn't get it.
As mentioned in the video, the main aim is to automatically adjust the UIScrollView contentSize to the size of the screen or to the size of the content in such way that on smaller devices scrolling is active and on larger devices scrolling is not active because it is not needed.
For this to achieve you've to set proper constraints to the content view so that the height is automatically calculated. From your video its visible that you're not setting the proper constraint to the last UITextFeild (this is important).
You have to give the top as well as the bottom constraint to the last UITextField so that contentView height is automatically calculated.
I have done a sample project which you can check here :
Sample Project
you can do this for working UIScrollView:
1)add a ViewController
2)put a UIScrollView in it
3)from "Simulated Metric" change size to Freeform. change the height to your desire height
4)add auto layouts to both UIScrollView and View (it's not needed)
5)put your controls in view and add auto layouts to them.
this should work :)
Related
I am creating a UIScrollView from xib, in which 3 view are there 2 UIViews and in middle an UIImageView. when I am setting constraints Xcode asked to set Y position constrains. But the problem is Y position constraint is blocking Scrollview to scroll down and automatically adjusting the views which looks ugly in landscape mode.
when I am delete that constraint it ask to fix height of subview. I searched a lot but I am new in autolayout so not understanding many of solutions. any help would be great.
You have to set all the height constraints in the content view.
But you also want the height of the Content to be proportional to the screen size.
To do this assign the height constraint of the imageview [equal|proportional|a-computation-of] to the view containing the UISCrollView.
It seems weird to skip levels of herarchy when assigning constraints between two views whose are not direct ancestor/sibling of each other but within a scrollview (at least) it is perfectly acceptable.
You are basically telling the scrollview that it's content has a known size and at same time setting this content to adapt dinamically to the screen size (if the constraints of the root uiview are set correctly)
UIView1
|---UIScrollView
|---UIView2
|---UIImageView [heightConstr.constant=UIView1.height-UIView2.height-UIView3.height-margins]
|---UIView3
This is the basic idea, to be done programmatically, then you can explore other solutions.
Unfortunately the constraint system in ios pretty much sucks when it's up to more complex equations involving more views for a single constraint.
UIScrollViewcan be tricky when adding constraints. You should always add a subView that will behave as the content view for your UIScrollView and all your subsequent views will go inside this content view.
UIView1
|---UIScrollView
|---UIContentView
|---UIView2
|---UIImageView
Set your UIScrollViewconstraints as you would normally but set your content view to have leading, trailing, top and bottom to the UIScrollView but also add two more constraints which will be equal width and equal height to the viewController.view but will have a low priority (So that whichever direction your content will increase in, that constraint will break and automatically increase the content size of the scroll view by taking in the inferred height of the content view). Now go on and add constraints on all your subview as you normally would. Which i'm assuming would be:
Your topmost view will have top and leading and trailing to its superView and also a fixed height.
Your bottom view will have leading, trailing and bottom to its superView and also a fixed height.
Your UIImageViewwill have a leading, trailing and top to top most view and bottom to the bottom view.
Edit:
Here is the screenshot just in case (To show the view hierarchy with the content view's constraints in the inspector)
I've been facing this issue from past 2 weeks and not yet got a solution.
I'm using UIScrollview in my application where the problem exists.
Generally in my app, there is dynamic text and images with different sizes will come from webservices. For example, imagine the Facebook Newsfeed. My application is similar to the Facebook newsfeed. Sometimes, there will be only text, sometimes there will be text and images. And comments for that post.
As i've seen in many links, the heirrarchy i'm following is SuperView-->UIScrollView-->Content View and the elements are placed in that content view. I'm assigning the constraints from the elements in the contentview to the Superview (ContentView --- constraints -- SuperView). When the content in the view exceeds the size of the superview, it has to scroll. But the scrollview content size is limited to the size of 600x600 i.e., in main.storyboard, when we design for W any x H any size. I've seen many tutorials and searched many sites. But following them gives me no luck.
Any help is appreciable.
Here is how to set up a scrollView in Interface Builder from scratch that works with Auto Layout.
Start with a new ViewController. Drag out a scrollView such that it fills the view. Untick Constrain to margins and constrain the left, top, right, and bottom edges of this scrollView to the left, top, right, and bottom of its superview with offsets of 0. This allows the scollView to fill the screen on any device in any orientation. You can make your scrollView take up less of the screen if you like, just make sure it is fully contrained.
Add a view to your scrollView. This should be the only top level view on your scrollView and it will serve as your contentView.
Constrain the left, top, right, and bottom edges of this contentView to the left, top, right, and bottom of the scrollView with offsets of 0. At this point, you will see warnings about ambiguous content size. That is because you haven't told it yet how big your content view will be.
To size the contentView, add width and height constraints to the contentView. If you want it to scroll, the width and height must be larger than the width and height of the scrollView itself. If you only want to scroll vertically, set the width of the contentView to be equal to the width of the scrollView. To do this, in the Document Outline view, control-drag from the contentView to the scrollView and select Equal Widths from the pop up.
If you want to be able to change the height of your contentView from code (to account for dynamic content), first create a height constraint for your contentView by control-dragging within the contentView and selecting Height from the pop up. Create an IBOutlet to the height constraint by control-dragging from the height constraint (found in the Document Outline view) to your ViewController's code. Give the outlet a name like scrollViewHeight then set the height with a value like scrollViewHeight.constant = 2000 when you need to change the scrollView's height.
Simply add your UIScrollView to your UIViewController's view in the storyboard and add the appropriate constraints in the interface builder.
Then, build your content view in the code and give it any frame you want, now start adding your controls to this content view and calculate the size of each one (especially the height), and at the end you have the total height of your controls.
Now set the frame of the content view to match that height and add it as a sub view to your scroll view, then set the content size in the code like this:
_scrollView.contentSize = contentView.frame.size;
Another note, do this changes to the sizes in the viewDidLayoutSubviews to avoid any problems with different screen sizes but be careful, this event is called many times so have a BOOL or something to ensure that the code that creates the view and add it to the scroll view is executed once, e.g. like this
- (void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];
if (! built) {
// Do everything I explained above here
built = YES;
[self.view layoutSubviews];
}
}
I can't understand how can I solve this auto layout problem, i have this View:
There is an UIScrollView with the elements you see in the View, but the View gives me this warning:
scrollview has ambiguous content width
I can't understand how to solve this problem, I want the the view is for the full screen size, and I want that the width will be the screen width, how I can solve it?
I observed its fix in XCode 7.3 and it is just 10 sec work. I made a video on it. Check here:
https://www.youtube.com/watch?v=yETZKqdaPiI
All you have to do, add a subview to UIScrollView with same width and height. Then select ViewController and press Reset to suggested constraint. Please check video for clear understanding.
Thanks
This is because you are not providing enough constraints so that Xcode can find Width of your scroll view.
You can see on your screen there isn't any constraints that can be satisfied to find width of scroll view.
You can do it by providing leading and trailing space of Image view which contains fix width. It also can be done with any other views. But i will prefer control which contains fix Height & Width So there isn't require to set hugging priority or Compress resistance.
Put everything in a View and that View put inside a ScrollView.
Editor -> Embed in -> View
The solutions is:
You have a UIImageView at the top. You set the width of the UIImageView to be the same as the width of the root view of the UIViewController
You set the leading and trailing space of the UIImageView to the UIScrollView to be both 0
You set the height of the UIImageView to be the height you want the image to be. And then you set the view mode of the UIImageView to be 'Aspect fit'.
I had the same problem a month ago. Add a constraint that makes the UIView inside the UIScrollView have the same size of the UIScrollView's content width. If you have multiple views inside the UIScrollView, put your UIViews inside a new UIView and make sure the new UIView has the same content width size as the UIScrollView.
Best regards,
I too faced this issue and the only way i got it solved was using the below strategy
Add a scroll view and set its constraint to fill in the screen
Add a UIview inside the scroll view lets call this view as the content view.
In this contentView, set top, bottom, left and right margins to 0 (of course from the scrollView which is the superView);
This should do it now you can follow step 3 and continue with your UI
Place your view inside the content view and add constraints to it accordingly.
Hope it helps
There are plenty of answers regarding scroll views with autolayout and plenty about scrollview paging, but I can't find a single thing that addresses both.
I'm not trying to do anything fancy...just 7 full-screen image views that I would like to scroll horizontally with paging, but for the sake of simplicity (ha!), I decided to attempt it all right in the storyboard.
The controller is set to freeform size with a width of 2240 (320*7). I then set it up the way Apple suggests for autolayout...
UIScrollview
/-----UIView
/----------Content (7 image views)
The scrollview has 0/0/0/0 constraints to all edges, as does the UIView inside.
When Paging Enabled is off, it behaves beautifully - exactly as expected. But once I turn Paging on, a swipe makes the view go crazy, scrolling the entire 2240 width, and then bouncing back and eventually landing on the proper page.
I know I have the tried-and-true option of just scrapping it all and doing it programmatically, but my stubbornness wants to figure this out. It must be possible!
I have a UIScrollView with paging and AutoLayout working perfectly fine. Here is my set up:
UIView // Main view
|---> Dummy UIView // See below
|---> UIScrollView
|---> Content UIView
|---> Page 1 Container
|---> Page 2 Container
The constraints I used are
Dummy UIView -> Parent UIView is whatever I want the size of the paging scrollview to be, and UIScrollView -> Dummy UIView is (0,0,0,0) on all sides. This is just regular auto layout stuff which creates a dummy UIView where I want to put the scrollview and a UIScrollView which completely fills the dummy UIView.
Refer to the Technote from Apple for AutoLayout and UIScrollViews: https://developer.apple.com/library/content/technotes/tn2154/_index.html
The content inside the scrollview has to have an intrinsic size. It cannot rely on the scrollview to get its size.
As indicated in the TechNote, set the constraints from all four sides of the Content View to the UIScrollView to (0,0,0,0). The exact values don't really matter since all you are telling the UIScrollView is that this is the view to get the contentSize from.
At this point Xcode will complain that Content View has no intrinsic size. And here is the trick: This is where we use the Dummy UIView that we created above. The size of the Dummy UIView is precisely the size of each page in the UIScrollView.
So we set the height of Content UIView equal to height of Dummy UIView and the width of the Content UIView equal to the number of pages times the width of the Dummy UIView using AutoLayout. (For the later change the multiplier in the constraint to be the number of pages).
Now create pages inside the Content UIView as you normally would and set Paging Enabled to yes on your UIScrollView and voila you have paging in a UIScrollView using AutoLayout.
I've tested this in IOS 6, 7 & 8.
Update:
Here is a sample project with this setup as requested:
https://github.com/kostub/PagingScrollView
Follow Working with Scroll Views to build paging UIScrollView with content in Interface Builder.
I'd also recommend using Stack View as a content view for your UIScrollView since it allows to essentially reduce layout complexity.
When you use traditional approach each entry view inside content view has 5 constraints at least:
leading to previous entry
top to parent
trailing to next entry
bottom to parent
equal width to scroll view
Stack View arrange its content automatically thus the only constraint each entry should have is "equal width to scroll view"
Check this project https://github.com/eugenebrusov/ios-stack-paging-scroll to see Stack View in action.
It is possible to use the scrollView's size to set the size of the contentView, contrary to https://developer.apple.com/library/ios/technotes/tn2154/_index.html; this was tested in iOS 8.2 beta 3.
Note that I did this programmatically, but hopefully this is useful to someone. The hierarchy is:
root: UIView
scrollView: UIScrollView
contentView: UIView
page0
page1
...
Add constraints to position scrollView relative to root and any siblings of scrollView.
Attach contentView sides to its superview (scrollView):
"H:|[contentView]|"
"V:|[contentView]|"
Add size equality constraints to contentView and scrollView; this is the part that contradicts TN2154 (which says "do not rely on the scroll view to get their size"):
contentView.height == scrollView.height
contentView.width == scrollView.width
Note: the above is made-up notation for a programmatically instantiated height constraint.
Lay out the pages relative to their superview(contentView); I did this by tacking the first page left/top to contentView left/top, and subsequent pages left/top to previous page right/top.
Credit to Koustub for getting me on the right track - his solution works, but with some fiddling I was able to eliminate the dummy view.
In my app, I have a hierarchy like Main view -> UIScrollView - > UISearchBar. The search bar covers the whole width of screen. But when it switches to landscape the scrollview adjust itself according to landscape and cover whole screen but its subviews like UISearchBar width remain same as in portrait. Plus I'm using Autolayout and I've correctly set their constraints (Leading and Trailing, width (greater than equal to 320) etc) in storyboard.
Also I know there are several answers for this in SO but almost everyone is saying set width again in willAutororate. But I have around 15 subviews in UIScrollview which I think is not possible to set programatically (as increase LOC) plus I think Autolayout must have some solution to it.
Scrollviews don't play very well with constraints. Here's an approach using constraints and Interface Builder that worked for me for having a vertically scrolling scrollview that doesn't require any manual or content size finagling and works with rotation:
Scrollview in a view controller positioned with constraints
A container (UIView) that is a subview of the scrollview positioned with constraints pinning each edge to the superview
Add all your additional subviews to the container view instead. Use constraints. Exceed the height of the scrollview to get a vertically scrolling scrollview.
There is one trick however to get rotation resizing to work automagically:
You have to add an additional constraint to the container view to match its width to the UIScrollview's width. It's strange that you have to do this, since pinning each side to the scrollview should do the trick, but alas it won't work with rotation if you don't add the additional constraint.
Here's what I mean:
try this :
this problem will solve by constraints only. I created a project and by using correct constraints its working fine for me ,
here I am going to show you how to add correct constraint one by one :
add scrollview and add constraints for scrollview only like in the screenshots :
2. now add search bar and add constraints for search bar too,
here below you can find out complete constraints for scrollview and search together:
You could use UIViewAutoresizing mask (autoresizingMask property) of your subviews.