I have a UITableView which I am able to add a header view to fairly easily. Many apps (like Facebook, for viewing events) have a headerView that when you pull down, the header view stays put but the rest of the table (the UITableViewCell's) are bouncing. When scrolling up the header disappears. How can I achieve this functionality?
Right now when I pull down the UITableView, even the headerView bounces as well
You can achieve this effect quite easily by adding a subview to the header view and adjusting its frame or transform when the table view is scrolled beyond the top, i.e. the y component of its contentOffset becomes negative.
Example (in a UITableViewController subclass):
- (void)viewDidLoad
{
[super viewDidLoad];
CGFloat headerHeight = 64.0f;
UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 0, headerHeight)];
UIView *headerContentView = [[UIView alloc] initWithFrame:headerView.bounds];
headerContentView.backgroundColor = [UIColor greenColor];
headerContentView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[headerView addSubview:headerContentView];
self.tableView.tableHeaderView = headerView;
}
//Note: UITableView is a subclass of UIScrollView, so we
// can use UIScrollViewDelegate methods.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat offsetY = scrollView.contentOffset.y;
UIView *headerContentView = self.tableView.tableHeaderView.subviews[0];
headerContentView.transform = CGAffineTransformMakeTranslation(0, MIN(offsetY, 0));
}
(to keep it simple, I've just used the first subview of the actual header view in scrollViewDidScroll:, you may want to use a property for that instead.)
Your UITableView is most likely working properly. Section headers are sticky by default in Plain style tables. Meaning as you scroll down the header stays at the top of the UITableView's frame until the next section header pushes it out of the way. The opposite occurs when you scroll up. Conversely you get the sticky behavior on section footers at the bottom of the UITableView's frame.
EDIT Misunderstood the original question:
I would suggest using a section header rather than the table view header to get the sticky behavior you're looking for.
Include a section in your data with no rows and put your table header's view in that section header view.
you can use this line in view did load: (swift 5.6)
tableView.bounces = false
There is 2 ways you can set the table header:
Using the .tableHeaderView property directly (this header scrolls with the table)
Overriding the - (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section function (this header stays static with the section)
By the sounds of it you should use the 2nd method instead of using the .tableHeaderView property
I currently have a custom class that implements UIScrollView.
I created one UIImageView and add it to a subview of the UIScrollView. It scrolls vertically and horizontally perfectly, but it seems to be ignoring the zooming stuff. Here is my code:
- (void) setUpBoard
{
// add board
UIImageView *imageHolder = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"grid.jpg"]];
[self addSubview:imageHolder];
self.contentSize = CGSizeMake(imageHolder.frame.size.width, imageHolder.frame.size.height);
self.indicatorStyle = UIScrollViewIndicatorStyleWhite;
self.maximumZoomScale = 5.0;
self.minimumZoomScale = 0.2;
self.zoomScale = 0.7;
self.clipsToBounds = YES;
}
How do I get it to zoom using standard pinch gestures? Any help is appreciated. Thanks!
From the UIScrollView Class Reference Overview:
The UIScrollView class can have a delegate that must adopt the UIScrollViewDelegate protocol. For zooming and panning to work, the delegate must implement both viewForZoomingInScrollView: and scrollViewDidEndZooming:withView:atScale:; in addition, the maximum (maximumZoomScale) and minimum (minimumZoomScale) zoom scale must be different.
I suspect that either you haven't assigned a delegate to the scroll view, or the delegate doesn't implement both of those methods.
I have a tabbed application that I would like to have a scroll view on. I already have a few text fields and labels on that tab. The problem is, the keyboard hides some of the text fields. How would I add a vertical scroll to prevent that?
You can accomplish what you are looking for without a scrollview.
In you delegate method for you textfield, You can change the frame of the viewController's view.
something like
- (void)textFieldDidBeginEditing:(UITextField *)textField;
{
CGRect newFrame = self.view.frame;
newFrame.origin.y = - 40; // move the view up to the point your textfield is visible
self.view.frame = newFrame;
}
Then in Set it back
- (void)textFieldDidEndEditing:(UITextField *)textField;
{
CGRect newFrame = self.view.frame;
newFrame.origin.y = 0;
self.view.frame = newFrame;
}
Usually I animate this with 0.33 seconds duration.
The solution requires quite a bit of code, but here's the general idea of what you need:
You will need to add the text fields (and everything else for consistency) to a scrollView.
You need to setup the scroll view to have vertical scrolling space only, but set the scrollEnabled to false so that the user can't scroll it manually.
Then you need to listen to UIKeyboardWillShowNotification and UIKeyboardWillHideNotification and manually scroll it up/down as required.
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)
}
}
My application uses a UINavigationController and the final view (detail view) lets you view an external website within the application using a UIWebView.
I'd like to free up some additional screen real estate when the user is viewing a webpage and wanted to emulate how Safari on iPhone works where their URL bar at the top scrolls up and off the screen when you're viewing content in the UIWebView that's below the fold.
Anyone have ideas on how to achieve this? If I set the navigationBarHidden property and roll my own custom bar at the top and set it and a UIWebView within a UIScrollView then there are scrolling issues in the UIWebView as it doesn't play nicely with other scrollable views.
Based on #Brian suggestion I made this code:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat height = navigationBar.frame.size.height;
CGFloat y = scrollView.bounds.origin.y;
if (y <= 0) {
CGRect frame = navigationBar.frame;
frame.origin.y = 0;
navigationBar.frame = frame;
} else if (tableView.contentSize.height > tableView.frame.size.height) {
CGFloat diff = height - y;
CGRect frame = navigationBar.frame;
frame.origin.y = -y;
navigationBar.frame = frame;
CGFloat origin = 0;
CGFloat h = height; // height of the tableHeaderView
if (diff > 0) {
origin = diff;
h = y;
}
frame = tableView.frame;
frame.origin.y = origin;
frame.size.height = tableView.superview.frame.size.height - origin;
tableView.frame = frame;
CGRect f = CGRectMake(0, 0, tableView.frame.size.width, h);
UILabel* label = [[UILabel alloc] initWithFrame:f];
tableView.tableHeaderView = label;
[label release];
}
}
My code has a UITableView but should work with any scrollable component. If you have other components than the navigationBar and the UIScrollView subclass, you should change the way the height of the scrollable component is calculated. Something like this:
frame.size.height = tableView.superview.frame.size.height - origin - otherComponentsHeight;
I needed to add a dumb tableHeaderView to have the desired behaviour. The problem was that when scrollViewDidScroll: is called the content has an offset, but the apparience in Mobile Safari is that the content is not scrolled until the navigationBar fully disappears. I tried first changing the contentOffset.y to 0, but obviously it didn't work since all the code relies on the scrolling mechanism. So I just added a tableHeaderView whose height is exactly the scrolled offset, so the header is never really seen, and the content appears to not scroll until the navigationBar fully disappears.
If you don't add the dumb tableHeaderView, then the scrollable component appears to scroll behind the navigationBar.
With the tableHeaderView, the scrollable component is actually scrolling (as seen in the scrollbar), but since there is a tableHeaderView whose height is exactly the same than the scrolled offset, the scrollable content appears to not be scrolling until the navigationBar fully disappears:
Have a delegate for the scrolling events in the UIWebView and when you initially start scrolling the UIWebView, have the UIWebView increase in height and have it's Y position decrease at the same time while simultaneously shifting the nav bar up in the Y direction. Once the nav bar has been completely shifted out of view, stop increasing the size of the UIWebView and just allow normal scrolling to occur.
This will give the illusion of the nav bar being part of the UIWebView as it scrolls off the screen.
Also, you'll need to do the reverse when you are scrolling in the opposite direction and are reaching the top of the content of the UIWebView.
Can't give you a straight answer, but have a look at iWebKit. Maybe that provides a solution. The demo, at least, contains a "full screen" item.