I have a NSCollectionViewFlowLayout which contains the following:
- (NSSize) itemSize
{
return CGSizeMake(self.collectionView.bounds.size.width, kItemHeight);
} // End of itemSize
- (CGFloat) minimumLineSpacing
{
return 0;
} // End of minimumLineSpacing
- (CGFloat) minimumInteritemSpacing
{
return 0;
} // End of minimumInteritemSpacing
I've tried to ways to make the layout responsive (set the width whenever resized). I've tried adding the following:
[[NSNotificationCenter defaultCenter] addObserver: self
selector: #selector(onWindowDidResize:)
name: NSWindowDidResizeNotification
object: nil];
- (void) onWindowDidResize: (NSNotification*) notification
{
[connectionsListView.collectionViewLayout invalidateLayout];
} // End of windowDidResize:
And this works fine if I expand the collection view (resize larger). But if I attempt to collapse the view (resize smaller), I get the following exceptions:
The behavior of the UICollectionViewFlowLayout is not defined because:
The item width must be less than the width of the UICollectionView minus the section insets left and right values, minus the content insets left and right values.
The relevant UICollectionViewFlowLayout instance is <TestListLayout: 0x106f70f90>, and it is attached to <NSCollectionView: 0x106f76480>.
Any suggestions on how I can resolve this?
NOTE1: This is macOS and not iOS (even though the error message states UICollectionViewFlowLayout).
NOTE2: Even though I receive the warning/error the layout width works, but I would like to figure out the underlying issue.
I had the same problem but in my case I resized view. #Giles solution didn't work for me until I changed invalidation context
class MyCollectionViewFlowLayout: NSCollectionViewFlowLayout {
override func shouldInvalidateLayout(forBoundsChange newBounds: NSRect) -> Bool {
return true
}
override func invalidationContext(forBoundsChange newBounds: NSRect) -> NSCollectionViewLayoutInvalidationContext {
let context = super.invalidationContext(forBoundsChange: newBounds) as! NSCollectionViewFlowLayoutInvalidationContext
context.invalidateFlowLayoutDelegateMetrics = true
return context
}
}
Hope it helps someone as it took me couple of evenings to find solution
This is because you are using the didResize event, which is too late. Your items are too wide at the moment the window starts to shrink. Try using:
func shouldInvalidateLayout(forBoundsChange newBounds: NSRect) -> Bool {
return true
}
...when overriding flow layout, to get everything recalculated.
The source code I posted in the question works fine as of macOS 10.14 with no issues. I added the following to my window which displays the collection view.
// Only Mojave and after is resizable. Before that, a full sized collection view caused issues as listed
// at https://stackoverflow.com/questions/48567326/full-width-nscollectionviewflowlayout-with-nscollectionview
if(#available(macOS 10.14, *))
{
self.window.styleMask |= NSWindowStyleMaskResizable;
} // End of macOS 10.14+
I put a UIScrollView in my nib's view, and linked it to a an IBOutlet property.
Now, when I do this in my viewDidLoad method, it seems to have no effect on the contentSize:
self.sv.backgroundColor = [UIColor yellowColor]; // this works
CGSize size = CGSizeMake(1000.0, 1000.0);
[self.sv setContentSize:size]; // this does not
It behaves as if the contentSize was the same as the frame. What's going on?
This started working when I turned off AutoLayout. Why?
I had the same problem. Auto Layout for UIScrollView is messed up.
Work around: Put everything in the UIScrollView into another UIView, and put that UIView as the only child of the UIScrollView. Then you can use Auto Layout.
If things near the end is messed up (the end of whichever direction your UIScrollView scrolls), change the constraint at the end to have the lowest possible priority.
I tried viewWillLayoutSubviews to update scrollView's contentSize, it worked for me.
- (void)viewDidLayoutSubviews
{
[self.bgScrollView setContentSize:CGSizeMake(320, self.view.frame.size.height* 1.5)];
}
Apple Doc
-(void)viewDidLayoutSubviews
Called to notify the view controller that its view has just laid out its subviews.
Discussion
When the bounds change for a view controller’s view, the view adjusts the positions of its subviews and then the system calls this method. However, this method being called does not indicate that the individual layouts of the view’s subviews have been adjusted. Each subview is responsible for adjusting its own layout.
Your view controller can override this method to make changes after the view lays out its subviews. The default implementation of this method does nothing.
The easiest/cleanest way is to set contentSize at viewDidAppear so you negate the effects of autolayout. This doesn't involve adding random views. However relying on load order for an implementation to work may not be the best idea.
Use this code. ScrollView setContentSize should be called async in main thread.
Swift:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
DispatchQueue.main.async {
var contentRect = CGRect.zero
for view in self.scrollView.subviews {
contentRect = contentRect.union(view.frame)
}
self.scrollView.contentSize = contentRect.size
}
}
Objective C:
- (void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];
dispatch_async(dispatch_get_main_queue(), ^ {
CGRect contentRect = CGRectZero;
for(UIView *view in scrollView.subviews)
contentRect = CGRectUnion(contentRect,view.frame);
scrollView.contentSize = contentRect.size;
});
}
There are two problems here. (1) viewDidLoad is too soon; you have to wait until after layout has taken place. (2) If you want to use autolayout with a scrollview that comes from a nib, then either you must use constraints to completely describe the size of the contentSize (and then you don't set the contentSize in code at all), or, if you want to set it in code, you must prevent the constraints on the scrollview's subviews from dictating the contentSize. It sounds like you would like to do the latter. To do so, you need a UIView that acts as the sole top-level subview of the scrollview, and in code you must set it to not use autolayout, enabling its autoresizingMask and removing its other external constraints. I show an example of how to do that, here:
https://github.com/mattneub/Programming-iOS-Book-Examples/blob/master/ch20p573scrollViewAutoLayout/ch20p573scrollViewAutoLayout/ViewController.m
But notice also the next example, which shows how to use constraints completely, instead of contentSize.
A SUPER easy way to use AutoLayout with UIScrollViews inside Interface Builder:
Step 1: Create a UIScrollView
Step 2: Create a UIView that is a child of your scroll view like so:
-UIScrollView
---UIView
-----Your other content
(We'll call this one contentView).
Step 3: In the size inspector, give this view a height and width (say, 320x700).
Step 4 (using AutoLayout): Create unambiguous constraints from your contentView to its superview (the UIScrollView): connect the 4 edges (top, leading, trailing, bottom), then give it a defined width and height that you want it to scroll too.
For example: If your scroll view spans the entire screen, you could give your content view a width of [device width] and a height of 600; it will then set the content size of the UIScrollView to match.
OR:
Step 4 (not using AutoLayout): Connect both of these new controls to your view controller using IB (ctrl+drag from each control to your view controller's .h #implementation). Let's assume each is called scrollView and contentView, respectively. It should look like this:
#interface YourViewController : UIViewController
#property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
#property (strong, nonatomic) IBOutlet UIView *contentView;
#end
Step 5 (not using AutoLayout): In the view controller's .h file add (actually, override) the following method:
-(void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
self.scrollView.contentSize = self.contentView.frame.size;
}
You can use this lines of code into your *.m file's
- (void)viewDidLoad{
[scroll setContentSize:CGSizeMake(320, 800)] ;
[scroll setScrollEnabled:TRUE];
[scroll setShowsVerticalScrollIndicator:NO];
[scroll setShowsHorizontalScrollIndicator:YES];
}
for this you need to take an IBOutlet property of UIScrollView into your *.h file this way:
IBOutlet UIScrollView *scroll;
And connect this from Storyboard.
Or,
You can use this method into your *.m file:
-(void)viewDidLayoutSubviews
{
[scroll setContentSize:CGSizeMake(320, self.view.frame.size.height* 1.5)];
// this will pick height automatically from device's height and multiply it with 1.5
}
This both solution works for me in xcode-5, xcode-6, xcode-6.1, xcode-6.2
Setting the contentSize in viewDidAppear is critical.
But I also had a variation of what worked in the 3.5 inch screen, and the 4 inch screen. The 4 inch screen worked, the older one does not. Both iOS 7. Bizarre is an understatement!
I could never get auto layout based on constraints to work. Since my view was already a subclass UIScrollView I solved it by overriding setContentView: and ignoring auto layouts zero height setContentSize: message.
#interface MyView : UIScrollView {}
#end
#implementation MyView
- (void)setContentSize:(CGSize)aSize {
if (aSize.height > 0)
[super setContentSize:aSize];
}
#end
I used to do set up the uiscrollview programmatically UNTIL I watched the following wonderful tutorial, step by step how to get uiscrollview and uiview to work: https://www.youtube.com/watch?v=PgeNPRBrB18
After watching the video you will start liking Interface Builder I am sure.
Vote up
Still not scrolling when dynamic height of labels exceeds view height.
I did what yuf's answer marked as correct above said to do (I added a content view to my scrollview and set the constraints leading, trailing, top bottom, and equal widths from the content view to the scroll view.) but still my view was not scrolling when the internal controls height exceeded the height of the scrollview.
Inside my content view I have an image and 3 labels below it. Each label adjusts their own height dependant on how much text is in them (they are set to word-wrap and numberoflines = 0 to achieve this).
The problem I had was my content view's height was not adjusting with the dynamic height of the labels when they exceeded the height of the scroll view/main view.
To fix this I worded out I needed to set the Bottom Space to Container constraint between my bottom label and the contentview and gave it a value of 40 (chosen arbitrarily to give it a nice margin at the bottom). This now means that my contentview adjusts its height so that there is a space between the bottom of the last label and itself and it scrolls perfectly!
Yay!
Try this out...
add all constraints like you do for UIView (See screenShot of my ViewControler in Storyboard)
Now trick begins. select your last object and select its bottom constraint. (See above screenShot, Instagram button's Bottom Constraint(Yellow line)) and Change the Constant in Size Inspector like in bellow screenshot.
i require Constant=8 but you can change as per your requirements.
this Constant is the Space between That Orange Button's Bottom and the scrollView.
EDIT
Make Sure about your view's hierarchy .
0) ViewController.view (optional)
1) UIScrollView
2) UIView (Rename as "contentView")
3) UIView (this view is your content that will make scrollView scroll)
I finally worked out my own solution to this problem because in my case I couldn't use the view controller's life cycle. Create your own scroll view subclass and use it instead of UIScrollView. This even worked for a scroll view inside a collection view cell.
class MyScrollView:UIScrollView {
var myContentSize:CGSize = CGSize.zero // you must set this yourself
override func layoutSubviews() {
super.layoutSubviews()
contentSize = myContentSize
}
}
My MyScrollView was defined in the nib with a tag of 90. If so this is a good way to set content size in the code in the parent view.
let scrollView = viewWithTag(90) as! MyScrollView
scrollView.myContentSize = ...
If you are using AutoLayout a really easy way to set the contentSize of a UIScrollView is just to add something like this:
CGFloat contentWidth = YOUR_CONTENT_WIDTH;
NSLayoutConstraint *constraintWidth =
[NSLayoutConstraint constraintWithItem:self.scrollView
attribute:NSLayoutAttributeTrailing
relatedBy:NSLayoutRelationEqual
toItem:self.scrollView
attribute:NSLayoutAttributeLeading
multiplier:1
constant:contentWidth];
[self.scrollView addConstraint:constraintWidth];
I got Autolayout to work for paginated scroll views whose pages occupy the full-width of the screen. The pages automatically resize according to the scroll view's size. I haven't tested this for lesser-width scroll views but do comment away if it works--I beleieve it should. Targeted for iOS 9, wrote code in Swift 2, used a mix of IB's and custom code in awakeFromNib.
Steps:
Define a full-screen scroll view.
Inside the scroll view, add a UIView (I called mine contentView) whose top, trailing, bottom, and leading edges to the scroll view are all zero; the height is equal to the scroll view's; but the width is the scroll view's width times the number of pages. If you're doing this visually, you will see your content view extend beyond your scroll view in Inteface Builder.
For every "page" inside the contentView, add Autolayout rules to put them side-by-side each other, but most importantly, give them each a constraint so that their widths are equal to the scroll view's, not the content view's.
Sample code below. embedChildViewController is just my convenience method for adding child VCs--do look at setupLayoutRulesForPages. I have exactly two pages so the function is too simple, but you can expand it to your needs.
In my view controller:
override func loadView() {
self.view = self.customView
}
override func viewDidLoad() {
super.viewDidLoad()
self.embedChildViewController(self.addExpenseVC, toView: self.customView.contentView, fillSuperview: false)
self.embedChildViewController(self.addCategoryVC, toView: self.customView.contentView, fillSuperview: false)
self.customView.setupLayoutRulesForPages(self.addExpenseVC.view, secondPage: self.addCategoryVC.view)
}
My custom view:
class __AMVCView: UIView {
#IBOutlet weak var scrollView: UIScrollView!
#IBOutlet weak var contentView: UIView!
#IBOutlet weak var pageControl: UIPageControl!
override func awakeFromNib() {
super.awakeFromNib()
self.scrollView.pagingEnabled = true
self.scrollView.bounces = true
self.scrollView.showsHorizontalScrollIndicator = false
self.scrollView.showsVerticalScrollIndicator = false
self.pageControl.numberOfPages = 2
self.contentView.backgroundColor = UIColor.blueColor()
self.scrollView.backgroundColor = UIColor.clearColor()
self.backgroundColor = UIColor.blackColor()
}
func setupLayoutRulesForPages(firstPage: UIView, secondPage: UIView) {
guard self.contentView.subviews.contains(firstPage) && self.contentView.subviews.contains(secondPage)
else {
return
}
let rules = [
"H:|-0-[firstPage]-0-[secondPage]-0-|",
"V:|-0-[firstPage]-0-|",
"V:|-0-[secondPage]-0-|"
]
let views = [
"firstPage" : firstPage,
"secondPage" : secondPage
]
let constraints = NSLayoutConstraint.constraintsWithVisualFormatArray(rules, metrics: nil, views: views)
UIView.disableAutoresizingMasksInViews(firstPage, secondPage)
self.addConstraints(constraints)
// Add the width Autolayout rules to the pages.
let widthConstraint = NSLayoutConstraint(item: firstPage, attribute: .Width, relatedBy: .Equal, toItem: self.scrollView, attribute: .Width, multiplier: 1, constant: 0)
self.addConstraint(widthConstraint)
}
}
I disabled editing, but how do I disable the selection interface from popping up? I don't want the user to be able to highlight text, or copy it etc.
It is important to preserve vertical scrolling.
textView.userInteractionEnabled = NO;
Ok then if you need to preserve scrolling, then create a scrollView, set it as an outlet and add the textview on it.
Then in viewWillAppear set the textview's height:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.descriptionTextView.text = #""; // set some text to determine the total height
self.descriptionTextView.frame = CGRectMake(self.descriptionTextView.frame.origin.x,
self.descriptionTextView.frame.origin.y,
self.descriptionTextView.frame.size.width,
self.descriptionTextView.contentSize.height);
self.descriptionTextView.userInteractionEnabled = NO;
//next set new content size for scroll view
self.descriptionScrollView.contentSize = CGSizeMake(self.descriptionScrollView.frame.size.width,
self.descriptionTextView.frame.origin.y + self.descriptionTextView.frame.size.height);
}
Swift 4, Xcode 10
Make sure you set the delegate to YourViewController
yourTextView.delegate = yourViewControllerInstance
Then this will disable highlighting, enable tapping links and allow scrolling
extension YourViewController: UITextViewDelegate {
func textViewDidChangeSelection(_ textView: UITextView) {
view.endEditing(true)
}
}
I have a bunch of UIViews on the screen. I would like to know what's the best to way to check if a particular view (which I have reference to) is intersection ANY other views. The way I am doing it right now is, iterating though all the subviews and check one by one if there's an intersection between the frames.
This doesn't seem very efficient. Is there a better way to do this?
There's a function called CGRectIntersectsRect which receives two CGRects as arguments and returns if the two given rects do intersect. And UIView has subviews property which is an NSArray of UIView objects. So you can write a method with BOOL return value that'll iterate through this array and check if two rectangles intersect, like such:
- (BOOL)viewIntersectsWithAnotherView:(UIView*)selectedView {
NSArray *subViewsInView = [self.view subviews];// I assume self is a subclass
// of UIViewController but the view can be
//any UIView that'd act as a container
//for all other views.
for(UIView *theView in subViewsInView) {
if (![selectedView isEqual:theView])
if(CGRectIntersectsRect(selectedView.frame, theView.frame))
return YES;
}
return NO;
}
To Achieve the same thing in swift as per the accepted answer then here is the function. Readymade Code. Just copy and use it as per the steps. By the way I am using Xcode 7.2 with Swift 2.1.1.
func checkViewIsInterSecting(viewToCheck: UIView) -> Bool{
let allSubViews = self.view!.subviews //Creating an array of all the subviews present in the superview.
for viewS in allSubViews{ //Running the loop through the subviews array
if (!(viewToCheck .isEqual(viewS))){ //Checking the view is equal to view to check or not
if(CGRectIntersectsRect(viewToCheck.frame, viewS.frame)){ //Checking the view is intersecting with other or not
return true //If intersected then return true
}
}
}
return false //If not intersected then return false
}
Now call this function as per the following -
let viewInterSected = self.checkViewIsInterSecting(newTwoPersonTable) //It will give the bool value as true/false. Now use this as per your need
Thanks.
Hope this helped.
In my case the views were nested, so I did this (works with both nested and not):
extension UIView {
func overlaps(other view: UIView, in viewController: UIViewController) -> Bool {
let frame = self.convert(self.bounds, to: viewController.view)
let otherFrame = view.convert(view.bounds, to: viewController.view)
return frame.intersects(otherFrame)
}
}
Hope it helps.
First, create some array that stores the frames of all of your UIViews and their associated reference.
Then, potentially in a background thread, you can run some collision testing using what's in the array. For some simple collision testing for rectangles only, check out this SO question: Simple Collision Algorithm for Rectangles
Hope that helps!
I have 20 UIImageView and i want change their image; but I don't want to create 20 IBOutlet, and I want to use tag value to change the image; I set the tag value in interface builder and after? If I want to change image at Imageview number 15? How can I do?
UIImageView *imageView=(UIImageView *)[self.view viewWithTag:*givetag*];
[imageView setImage:[UIImage imageNamed:#"nameof yourimage"]];
If you use tags you can identify your tagged view (UIImageView is a subclass of UIView, which has the tag attribute) like this:
- (UIView *)viewWithTag:(NSInteger)tag
So if you call this method on your superview (which all the UIImageViews reside in), you should do it like this:
UIImageView *myImageView = (UIImageView *)[myAwesomeSuperview viewWithTag:15];
(Documentation I found using Google).
P.S: if you think it is too much work to add 20 IBOutlets, I recommend you create the UIImageViews programmatically as well. This way you will not need a xib file at all, write a small piece of code and have better maintenance with less effort.
SWIFT, April 2015:
func createUIImageViews()
{
for i in 0...99
{
var imageView:UIImageView = UIImageView(frame: CGRectMake(CGFloat(0), CGFloat(0), CGFloat(100), CGFloat(100)))
imageView.userInteractionEnabled = true
imageView.tag = i
imageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "onImageViewTap:"))
self.view.addSubview(imageView)
}
}
func onImageViewTap(sender:UITapGestureRecognizer)
{
println("TAP: \(sender.view!.tag)")
}