Scroll Collection view to the top - ios

I have a following collection view. When the user scrolls the view up, I want the collection view to go all the way up. Similarly, when it is scrolled down, I want it to come back to its original position.
I have a uiview and imageView above the collectionview.
Now, If this was a tableview, I would have used header. How do i achieve this behavious. I am out of Ideas.
Thanks in advance

UICollectionView is the sub-class of UIScrollView so you can achieve what you want is just by the scrollview delegate method and the constraints of your UIView and UIImageView upon the UICollectionView.
Here I am going to give you one example to achieve this with scrollview delegate.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if scrollView == collectionView{
if scrollView.contentOffset.y == 0{
UIView.animate(withDuration: 0.5) { () -> Void in
self.constTopTagHeight.constant = 175 // Your UIView and imageview constraints adjust.
self.view.layoutIfNeeded()
}
}
else{
UIView.animate(withDuration: 0.5) { () -> Void in
self.constTopTagHeight.constant = 0 // Your UIView and imageview constraints adjust.
self.view.layoutIfNeeded()
}
}
}
}
Hope this help you.

Related

Nested scrollview with Vertical scrolling for both [duplicate]

I need to do this app that has a weird configuration.
As shown in the next image, the main view is a UIScrollView. Then inside it should have a UIPageView, and each page of the PageView should have a UITableView.
I've done all this so far. But my problem is that I want the scrolling to behave naturally.
The next is what I mean naturally. Currently when I scroll on one of the UITableViews, it scrolls the tableview (not the scrollview). But I want it to scroll the ScrollView unless the scrollview cannot scroll cause it got to its top or bottom (In that case I'd like it to scroll the tableview).
For example, let's say my scrollview is currently scrolled to the top. Then I put my finger over the tableview (of the current page being shown) and start scrolling down. I this case, I want the scrollview to scroll (no the tableview). If I keep scrolling down my scrollview and it reaches the bottom, if I remove my finger from the display and put it back over the tebleview and scroll down again, I want my tableview to scroll down now because the scrollview reached its bottom and it's not able to keep scrolling.
Do you guys have any idea about how to implement this scrolling?
I'm REALLY lost with this. Any help will be greatly appreciate it :(
Thanks!
The solution to simultaneously handling the scroll view and the table view revolves around the UIScrollViewDelegate. Therefore, have your view controller conform to that protocol:
class ViewController: UIViewController, UIScrollViewDelegate {
I’ll represent the scroll view and table view as outlets:
#IBOutlet weak var scrollView: UIScrollView!
#IBOutlet weak var tableView: UITableView!
We’ll also need to track the height of the scroll view content as well as the screen height. You’ll see why later.
let screenHeight = UIScreen.mainScreen().bounds.height
let scrollViewContentHeight = 1200 as CGFloat
A little configuration is needed in viewDidLoad::
override func viewDidLoad() {
super.viewDidLoad()
scrollView.contentSize = CGSizeMake(scrollViewContentWidth, scrollViewContentHeight)
scrollView.delegate = self
tableView.delegate = self
scrollView.bounces = false
tableView.bounces = false
tableView.scrollEnabled = false
}
where I’ve turned off bouncing to keep things simple. The key settings are the delegates for the scroll view and the table view and having the table view scrolling being turned off at first.
These are necessary so that the scrollViewDidScroll: delegate method can handle reaching the bottom of the scroll view and reaching the top of the table view. Here is that method:
func scrollViewDidScroll(scrollView: UIScrollView) {
let yOffset = scrollView.contentOffset.y
if scrollView == self.scrollView {
if yOffset >= scrollViewContentHeight - screenHeight {
scrollView.scrollEnabled = false
tableView.scrollEnabled = true
}
}
if scrollView == self.tableView {
if yOffset <= 0 {
self.scrollView.scrollEnabled = true
self.tableView.scrollEnabled = false
}
}
}
What the delegate method is doing is detecting when the scroll view has reached its bottom. When that has happened the table view can be scrolled. It is also detecting when the table view reaches the top where the scroll view is re-enabled.
I created a GIF to demonstrate the results:
Modified Daniel's answer to make it more efficient and bug free.
#IBOutlet weak var scrollView: UIScrollView!
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var tableHeight: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
//Set table height to cover entire view
//if navigation bar is not translucent, reduce navigation bar height from view height
tableHeight.constant = self.view.frame.height-64
self.tableView.isScrollEnabled = false
//no need to write following if checked in storyboard
self.scrollView.bounces = false
self.tableView.bounces = true
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 20
}
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let label = UILabel(frame: CGRect(x: 0, y: 0, width: tableView.frame.width, height: 30))
label.text = "Section 1"
label.textAlignment = .center
label.backgroundColor = .yellow
return label
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = "Row: \(indexPath.row+1)"
return cell
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if scrollView == self.scrollView {
tableView.isScrollEnabled = (self.scrollView.contentOffset.y >= 200)
}
if scrollView == self.tableView {
self.tableView.isScrollEnabled = (tableView.contentOffset.y > 0)
}
}
Complete project can be seen here:
https://gitlab.com/vineetks/TableScroll.git
After many trials and errors, this is what worked best for me. The solution has to solve two needs 1) determine who's scrolling property should be used; tableView or scrollView? 2) make sure that the tableView doesn't give authority to the scrollView until it has reached the top of it's table/content.
In order to see if the scrollview should be used for scrolling vs the tableview, i checked to see if the UIView right above my tableview was within frame. If the UIView is within frame, it's safe to say the scrollView should have authority to scroll. If the UIView is not within frame, that means that the tableView is taking up the entire window, and therefor should have authority to scroll.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if scrollView.bounds.intersects(UIView.frame) == true {
//the UIView is within frame, use the UIScrollView's scrolling.
if tableView.contentOffset.y == 0 {
//tableViews content is at the top of the tableView.
tableView.isUserInteractionEnabled = false
tableView.resignFirstResponder()
print("using scrollView scroll")
} else {
//UIView is in frame, but the tableView still has more content to scroll before resigning its scrolling over to ScrollView.
tableView.isUserInteractionEnabled = true
scrollView.resignFirstResponder()
print("using tableView scroll")
}
} else {
//UIView is not in frame. Use tableViews scroll.
tableView.isUserInteractionEnabled = true
scrollView.resignFirstResponder()
print("using tableView scroll")
}
}
hope this helps someone!
None of the answers here worked perfectly for me. Each one had it's owned nuanced problem (needing to do a repeated swipe when one scrollview hit it's bottom, or the scroll indicator not looking correct, etc), so figured I'd throw in another answer.
Ole Begemann has a great write up on doing this exactly https://oleb.net/blog/2014/05/scrollviews-inside-scrollviews/
Despite being an old post, the concepts still apply to the current APIs. Additionally, there is a maintained (Xcode 9 compatible) Objective-C implementation of his approach https://github.com/eyeem/OLEContainerScrollView
If you are facing problem with the nested scrolling issue , here tis the simplest solution for it .
go to your design screen
select your scroll view and then disable bounce on scroll
if your view uses table view inside scroll view then disable bounce on scroll of the table view as well
run and check it is solved
check how to disable bounce on scroll of a scroll view
check how to disable bounce on scroll of a tableview view
I was struggling with this problem, too. There is a very simple solution.
In interface builder:
create simple ViewController
add a simple View, it will be our header, and constrain it to superview
it's the red view on the example below
I have added 12px from top, left and right, and set fixed height to 128px
embed a PageViewController, making sure it is constrained to the superview, and not the header
Now, here comes the fun part: for each page you add, make sure its tableView has an offset from top. Thats it. You can do if with this code, for example (assuming you use UITableViewController as a page):
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
let tables = viewControllers.compactMap { $0 as? UITableViewController }
tables.forEach {
$0.tableView.contentInset = UIEdgeInsets(top: headerView.bounds.height, left: 0, bottom: 0, right: 0)
$0.tableView.contentOffset = CGPoint(x: 0, y: -headerView.bounds.height)
}
}
No messy scroll inside scroll inside table view, no mangling with delegates, no duplicated scrolls, perfectly natural behavior. If you can't see the header, it is probably because of the tableView background color. You have to set it to clear, for the header to be visible from under the tableView.
I think there are two options.
Since you know the size of the scroll view and the main view, you are unable to tell whether the scroll view hit the bottom or not.
if (scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height)) {
// reach bottom
}
So when it hit; you basically set
[contentScrollView setScrollEnabled:NO];
and other way around for your tableView.
The other thing, which is more precise I think, is to add Gesture to your views.
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc]
initWithTarget:self action:#selector(respondToTapGesture:)];
// Specify that the gesture must be a single tap
tapRecognizer.numberOfTapsRequired = 1;
// Add the tap gesture recognizer to the view
[self.view addGestureRecognizer:tapRecognizer];
// Do any additional setup after loading the view, typically from a nib
So when you add Gesture, you can simply control the active view by changing setScrollEnabled in the respondToTapGesture.
I found an awesome library
MXParallaxHeader
In Storyboard just set UIScrollView class to MXScrollView then magic happens.
I used this class to handle my UIScrollView when I embed a UIPageViewController container view. even you can insert a parallax header view for more detail.
Also, this library provides Cocoapods and Carthage
I attached an image below which represent UIViewHierarchy.
MXScrollView Hierarchy
SWIFT 5
I had some trouble using Vineet's answer for when I could not guarantee the scrollView content offset (Y) due to various different screen sizes. To resolve this, I changed the first trigger event of when the tableView's scroll gets enabled.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if scrollView.bounds.contains(button.frame) {
tableView.isScrollEnabled = true
}
if scrollView == tableView {
self.tableView.isScrollEnabled = (tableView.contentOffset.y > 0)
}
}
The scrollView.bounds.contains will check if a given element's frame is FULLY within the scrollView's visible content. I set this to a button that I have below the tableView. You could set this to your tableVIew's frame instead if your only condition is that your tableView is fully visible.
I left the original implementation of when to disable the tableView's scroll and it works very well.
I tried the solution marked as the correct answer, but it was not working properly. The user need to click two times on the table view for scroll and after that I was not able to scroll the entire screen again. So I just applied the following code in viewDidLoad():
tableView.addGestureRecognizer(UISwipeGestureRecognizer(target: self, action: #selector(tableViewSwiped)))
scrollView.addGestureRecognizer(UISwipeGestureRecognizer(target: self, action: #selector(scrollViewSwiped)))
And the code below is the implementation of the actions:
func tableViewSwiped(){
scrollView.isScrollEnabled = false
tableView.isScrollEnabled = true
}
func scrollViewSwiped(){
scrollView.isScrollEnabled = true
tableView.isScrollEnabled = false
}
One easy trick, if you want to achieve it is replacing parent scrollview with normal container view.
Adding a pan gesture on container view, you can play with top constraint of first view to assign negative values. You can keep a check of page View's origin if it achieves to top you can start assigning that value on content offset of the pageView's child view. Until user achieves the table view in a state of top most view in container view, you can keep page tableView's scrolling disabled and allow scrolling manually by setting content offset.
So initially the page view height will be collapsed (or say out of screen) or less at bottom. Later on scrolling down it will expand to take more space.
Gesture will automatically stop responding if out of frames say on nav bar or other view outside container view.
Gestures are a key to user interactive transitions used in many apps. You can mimic scroll for a certain time with it.
In my case I'm using constraint for height like that:
self.heightTableViewConstraint.constant = self.tableView.contentSize.height
self.scrollView.contentInset.bottom = self.tableView.contentSize.height
Below code works great for me
As I wanted to show some header after some scroll and table view supposed to scroll
And in ViewDidLoad add
override func viewDidLoad() {
super.viewDidLoad()
mainScrollView.delegate = self
}
Change 265 to whatever number you want to stop upper scroll
extension AccountViewController: UIScrollViewDelegate {
func scrollViewDidScroll(_ scrollView: UIScrollView) {
print(notebookTableView.contentOffset.y)
if notebookTableView.contentOffset.y < 265 {
if notebookTableView.contentOffset.y > 0 {
mainScrollView.setContentOffset(notebookTableView.contentOffset, animated: false)
} else {
mainScrollView.setContentOffset(CGPoint(x: 0.0, y: 0.0), animated: false)
}
} else {
mainScrollView.setContentOffset(CGPoint(x: 0.0, y: 265), animated: false)
}
}
}
CGFloat tableHeight = 0.0f;
YourArray =[response valueForKey:#"result"];
tableHeight = 0.0f;
for (int i = 0; i < [YourArray count]; i ++) {
tableHeight += [self tableView:self.aTableviewDoc heightForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:0]];
}
self.aTableviewDoc.frame = CGRectMake(self.aTableviewDoc.frame.origin.x, self.aTableviewDoc.frame.origin.y, self.aTableviewDoc.frame.size.width, tableHeight);
Maybe brute-force, but working perfectly if cell heights are the same: by the way, I use auto layout.
for the tableView (or collectionView or whatever), set an arbitrary height in storyboard, and make an outlet to class. Wherever appropriate, (viewDidLoad() or...) set the tableView's height big enough so that tableView doesn't need to scroll. (need to know the number of rows in advance) Then only the outer scrollView will scroll nicely.

How to prevent a child view to zoom inside scrollview

I have a scroll view and inside the scrollview I am having a content view with few subview inside this content view. My requirement is to zoom the content view but not the subview of content view.
Can anyone faced this before, or did the same. Any help would be appreciated.
Thanks in advance.
Scroll view just apply transform to contentView. This transform applied to all children in contentView. So you can apply inverted transform to children to negate parent transform.
func scrollViewDidZoom(_ scrollView: UIScrollView) {
guard let content = viewForZooming(in: scrollView) else {
return
}
let t = content.transform.inverted()
for v in content.subviews {
v.transform = t
}
}

Swift: how to deal with tableView when tableView width is wider than screen size?

The scene I need to implement the attached picture.
When I try to implement the bottom form, I meet some problems.
The bottom form has following requirements:
top 2 lines should stick at the head, and not allow to scroll up/down. I use table section head to implement.
all the other rows could scroll up/down and clickable. I use a table view to implement
since the app support bigger text, when text is bigger, the screen size could not display all the tableView, so in this case, the whole tableview should support horizontally scroll.
when tableview row data is different from the "currentBitting", which has a value of "33342431", the individual label should show background colour.
each column should be aligned for the table
Following is the idea how I implement:
To achieve all these requirements, I use tableView to implement. Each character in the array item use label to display.
I use the max width and regular width to define the width of each column
When text font size changes, I try to set the bottom tableView
contentSize = current new content size in "viewWillLayoutSubViews()"
I add a background colour for the section head, otherwise, when bottom tableview scroll up, it will overlap the section head and offscreen text background colour does not render. So I add section head background colour to avoid this problem.
Currently, the problem is the horizontal scroll does not work. Very strange.
To be honest, I tried quite a lot of ways:
bottom form first uses a parent scrollView, then put a sub tableView. Problem: top header is hard to stick or vertically scroll not that smooth. I pasted my scrollViewDidScroll part. It works. But vertically scroll not that smooth. If anyone could help to improve it, I will be very appreciated.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let recognizer = scrollView.panGestureRecognizer
let distance = recognizer.translation(in: scrollView)
let deltaHeight:CGFloat = parentScrollView.contentSize.height - parentScrollView.frame.height
let goingUp = distance.y < 0 //going up
if distance.y != 0 {
if goingUp {
parentScrollView.contentOffset.y = 0
switch recognizer.state {
case .began,.changed:
if bottomTableview.contentOffset.y < deltaHeight {
bottomTableview.contentOffset.y -= distance.y
recognizer.setTranslation(.zero, in: scrollView)
}
case .ended:
if bottomTableview.contentOffset.y > deltaHeight{
bottomTableview.contentOffset.y = deltaHeight
UIView.animate(withDuration: 0.1, animations: {
scrollView.layoutIfNeeded()
})
}
default:
break
}
}
else{
switch recognizer.state {
case .began,.changed:
if bottomTableview.contentOffset.y > 0 {
bottomTableview.contentOffset.y -= distance.y
recognizer.setTranslation(.zero, in: scrollView)
}
case .ended:
if bottomTableview.contentOffset.y < 0 {
bottomTableview.contentOffset.y = 0
UIView.animate(withDuration: 0.1, animations: {
scrollView.layoutIfNeeded()
})
}
default:
break
}
}
}
}
collection view to implementing. But I don't know how to select a whole line to get the data and how to stick the top header
Does anyone have some better idea to implement this case? Very appreciated for your help.
Data to use in the table view is:
let extensionCodeArray = ["Position", "Current Bitting", "11407", "10253", "10492", "14195", "11665", "10547", "12332", "12536", "10211", "11034", "10725", "11036", "12928"]
let extensionResultBitting = ["12345678", "33342431", "33133244", "33243134", "32343134", "33134243", "31343234", "33342134", "31344233", "34342133", "31334342", "33134342", "34343132", "34231343", "32431343"]
I solved the problem. The idea is below:
define a collection view, set its numberOfItemsInSection = 1
for the collectionView, set its
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize --> return CGSize(width: contentSize.width, height: collectionView.frame.size.height)
The cotentSize is calculated in advance for the final form
Customerize the UICollectionViewCell, inside which implementing the tableView data source and delegate. All the datasource for the tableView get from a protocol defined in the UICollectionViewCell. Outerside collectionView is the delegate for the protocol
Done.
For first solution you tried.
UITableView is a subclass of UIScrollView, which means UITableView also have scrollViewDidScroll(_ scrollView: UIScrollView) event.
To solve this, you could simply do the following. Set a tag to tableView or scrollView to identify it.
1. For example, to identify the scrollView, add the following line after where you initialized the scrollView.
scrollView.tag = 101
In
func scrollViewDidScroll(_ scrollView: UIScrollView)
func scrollViewDidScroll(_ scrollView: UIScrollView)
{
if scrollView.tag == 101 {
// Triggered by scrollView
} else {
// Triggered by tableView
}
}

Move SubView of ChildViewController using scrollViewDidScroll

I am using a viewController to handle two ChildViewControllers, each containing a UITableView. Would it be possible to set the the position y of a SubView of viewController (e.g. a UILabel) depending on the scrollView.contentOffset of the current ChildViewController?
It works fine with its own subviews already,..
func scrollViewDidScroll(_ scrollView: UIScrollView) {
self.testConstt.constant = scrollView.contentOffset.y
}
Thanks for helping!
Just observe the correct scroll view using a conditional statement. I assume the scroll views of the children are table views, so you may do something like this:
let tableViewA = UITableView(...)
let tableViewB = UITableView(...)
let someScrollView = UIScrollView()
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if scrollView == tableViewA {
// observe a specific table view's scroll view and do something
} else if scrollView == someScrollView {
// observe a specific scroll view and do something
}
}
Remember, UITableView is a subclass of UIScrollView so they can be treated the same in scrollViewDidScroll(_ scrollView:).

conflict scrolling scrollview and tableview

I have a scrollview that contain some element (uiimage, webview ,...)
in buttom of scrollview add tableview (comments list). Problem: although tableview is part of scrollview, but scrollview scroll separate and tableview scrolling separate!
I want at the end of scrollview and start tableview scrollview scrolling tableview and tableview scroll disabled.
I used it code:
Swift:
override func intrinsicContentSize() -> CGSize {
self.layoutIfNeeded()
return CGSizeMake(UIViewNoIntrinsicMetric, contentSize.height)
}
Objective C:
-(CGSize)intrinsicContentSize{
[self layoutIfNeeded];
return CGSizeMake(UIViewNoIntrinsicMetric, contentSize.height)}
but don't work.
thanks for help
That happens because it is the behavior of having a table view inside a scroll view. That should be happening.
Solution: Destroy the scrollView, and implement a tableView with a header view, wish that header view it will be the view with uiimage, webview etc... and the tableView it will be your comments. This is the best way of implementing what you want, that is if i understood right what you actually want.
Adding a header to a table view example:
self.tableView.tableHeaderView = topView // where top view is the view wish contains your uimage, buttons etc...
Avoid bounce of ScrollView when we scroll the tableview. I have added the below line of code.It worked for me.
self.scrollView.delegate = self
scrollView.contentSize = CGSize(width: self.view.frame.width, height: 500)
scrollView.showsVerticalScrollIndicator = true
scrollView.tag = 1
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
if scrollView.tag != 1 {
self.scrollView.bounces = false
}
}
Thanks

Resources