Zooming in UIScrollView with another UIScrollView as the content - ios

I'm trying to accomplish a scenario where I can zoom in on a UIScrollView. I've seen around that the best way to accomplish this is to have an all-encompassing scrollView, which supports scrolling, and having the other UIScrollViewView inside (instead of the normal application of having a UIImageView inside)
Here's what I have:
class Editor: UIViewController, UIScrollViewDelegate {
let menuHeight = CGFloat(60)
var editor: LevelScrollView? = nil
var scrollProxy = UIScrollView()
override func viewDidLoad() {
let contentFrame = CGRectMake(0,menuHeight,self.view.frame.width,self.view.frame.height-menuHeight)
scrollProxy.delegate = self
scrollProxy.backgroundColor = UIColor.redColor()
scrollProxy.frame = contentFrame
scrollProxy.showsHorizontalScrollIndicator = false
scrollProxy.showsVerticalScrollIndicator = false
scrollProxy.bounces = false
let editor = LevelScrollView(reference: scrollProxy)
self.editor = editor
scrollProxy.addSubview(editor)
scrollProxy.contentSize = self.editor!.contentSize
scrollProxy.minimumZoomScale = 1.0
scrollProxy.zoomScale = scrollProxy.minimumZoomScale
scrollProxy.maximumZoomScale = 20.0
}
func scrollViewWillBeginZooming(scrollView: UIScrollView, withView view: UIView?) {
print("scrollViewWillBeginZooming")
}
func scrollViewDidEndZooming(scrollView: UIScrollView, withView view: UIView?, atScale scale: CGFloat) {
print("scrollViewDidEndZooming")
}
func scrollViewDidZoom(scrollView: UIScrollView) {
print("scrollViewDidZoom")
}
func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
return editor
}
}
A few notes:
LevelScrollView is a UIScrollView
I removed a few things not pertaining to this issue, let me know if it would be helpful to see the entire thing.
The viewForZoomingIn delegate function is being called, with a valid UIView returning (the LevelScrollView), but the other three are never called no matter what I do.
Because of these things zooming isn't working. How would I accomplish this successfully?
Thanks!

The only solution I was able to find for this was to embed the entire scrollview in a separate UIView, and then enable zooming for that.

Related

how to check if which collectionview is scrolled in swift

I'm developing app which contains 3 UICollectionViews in one ViewController.
I can know if UICollectionView is scrolled or not with this code
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
let isScrolling: Bool = colView.isDragging || colView.isDecelerating
}
Specifically I want to know if which UICollectionView did scroll in scrollViewDidEndDragging.
But the problem is that I can't know if which collectionview is scrolled before.
Like I want to know if colview2 is scrolling or not.
Is there anybody who knows this solution? I searched solution on Google and Stackoverflow but I don't think there's such a solution for this problem.
Help will be much appreciated.
You can Do it by set tag to CollectionView And Scroll View Delegate method scrollViewDidEndDecelerating Here is the Code :
First Set tag top your CollectionView in your ViewDidLoad method :
firstCollectionView.tag = 1
secondCollectionView.tag = 2
thirdCollectionView.tag = 3
2.Create three Property Observer variable like this upside of your viewDidload:
var whichCollectionViewScrolled = "" {
willSet{
print(newValue)
}
}
var isFirstCollectionViewScrolled = false {
willSet{
print("First CollectionView Scrolled : \(newValue)")
}
}
var isSecondCollectionViewScrolled = false {
willSet{
print("Second CollectionView Scrolled : \(newValue)")
}
}
var isthirdCollectionViewScrolled = false {
willSet{
print("Third CollectionView Scrolled : \(newValue)")
}
}
1.lastly inside of your scrollViewDelegate method cast your scrollview instance and check the tag value like this :
extension ViewController: UIScrollViewDelegate {
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
if let collectionView = scrollView as? UICollectionView {
switch collectionView.tag {
case 1:
whichCollectionViewScrolled = "First"
isFirstCollectionViewScrolled = true
isSecondCollectionViewScrolled = false
isthirdCollectionViewScrolled = false
case 2:
whichCollectionViewScrolled = "second"
isFirstCollectionViewScrolled = false
isSecondCollectionViewScrolled = true
isthirdCollectionViewScrolled = false
case 3:
whichCollectionViewScrolled = "Third"
isFirstCollectionViewScrolled = false
isSecondCollectionViewScrolled = false
isthirdCollectionViewScrolled = true
default:
whichCollectionViewScrolled = "unknown"
}
} else{
print("cant cast")
}
}
Hope it will help You .
Scroll view is the superClass of UICollectionView. Just check that scroll view and collection view you are storing are the same instance.
if collectionView === scrollView {
}
Like this.

Having trouble with LargeTitle and a segmented control with a table view

Sample project can be found at https://github.com/SRowley90/LargeTitleIssueTestiOS
I am trying to position a segmented control below the Large title in an iOS app. I have a UIToolbar which contains the segmented control inside.
When scrolling up the title and toolbar behave as expected.
When scrolling down the navigation bar is correct, but it doesn't push the UITabBar or the UITableView down, meaning the title goes above the segmented control as can be seen in the images below.
I'm pretty sure it's something to do with the constraints I have set, but I can't figure out what.
The TabBar is fixed to the top, left and right.
The TableView is fixed to the bottom, left and right.
The tableView is fixed vertically to the TabBar
I have the position UITabBarDelegate method set:
func position(for bar: UIBarPositioning) -> UIBarPosition {
return .topAttached
}
Take the delegation of the tableView somewhere:
tableView.delegate = self
Override the scrollViewDidScroll and update toolbar position appearance (since the real position should not change according to have that nice bounce effect.
extension ViewController: UIScrollViewDelegate {
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
var verticalOffset = scrollView.contentOffset.y + defaultNavigationBarHeight
if scrollView.refreshControl?.isRefreshing ?? false {
verticalOffset += 60 // After is refreshing changes its value the toolbar goes 60 points down
print(toolbar.frame.origin.y)
}
if verticalOffset >= 0 {
toolbar.transform = .identity
} else {
toolbar.transform = CGAffineTransform(translationX: 0, y: -verticalOffset)
}
}
}
You can use the following check before applying transformation to make it more reliable and natural to default iOS style:
if #available(iOS 11.0, *) {
guard let navigationController = navigationController else { return }
guard navigationController.navigationBar.prefersLargeTitles else { return }
guard navigationController.navigationItem.largeTitleDisplayMode != .never else { return }
}
Using UIScrollViewDelegate didn't work well with CollectionView and toolbar for me. So, I did:
final class CollectionViewController: UICollectionViewController {
private var observesBag: [NSKeyValueObservation] = []
private let toolbar = UIToolbar()
override func viewDidLoad() {
super.viewDidLoad()
let statusBarHeight = UIApplication.shared.statusBarFrame.height
let navigationBarHeight = navigationController?.navigationBar.frame.height ?? 0
let defaultNavigationBarHeight = statusBarHeight + navigationBarHeight
let observation = navigationController!
.navigationBar
.observe(\.center, options: NSKeyValueObservingOptions.new) { [weak self] navBar, _ in
guard let self = self else { return }
let newNavigatonBarHeight = navBar.frame.height + statusBarHeight
let yTranslantion = newNavigatonBarHeight - defaultNavigationBarHeight
if yTranslantion > 0 {
self.toolbar.transform = CGAffineTransform(
translationX: 0,
y: yTranslantion
)
} else {
self.toolbar.transform = .identity
}
}
observesBag.append(observation)
}
}
Observe the "center" of the navigationBar for changes and then translate the toolbar in the y-axis.
Even though it worked fine when I tried to use this solution with UIRefreshControl and Large Titles it didn't work well.
I set up the refresh control like:
private func setupRefreshControl() {
let refreshControl = UIRefreshControl()
self.webView.scrollView.refreshControl = refreshControl
}
the height of the UINavigationBar is changed after the complete refresh triggers.

How can I mimic the bottom sheet from the Maps app?

Can anyone tell me how I can mimic the bottom sheet in the new Apple Maps app in iOS 10?
In Android, you can use a BottomSheet which mimics this behaviour, but I could not find anything like that for iOS.
Is that a simple scroll view with a content inset, so that the search bar is at the bottom?
I am fairly new to iOS programming so if someone could help me creating this layout, that would be highly appreciated.
This is what I mean by "bottom sheet":
I don't know how exactly the bottom sheet of the new Maps app, responds to user interactions. But you can create a custom view that looks like the one in the screenshots and add it to the main view.
I assume you know how to:
1- create view controllers either by storyboards or using xib files.
2- use googleMaps or Apple's MapKit.
Example
1- Create 2 view controllers e.g, MapViewController and BottomSheetViewController. The first controller will host the map and the second is the bottom sheet itself.
Configure MapViewController
Create a method to add the bottom sheet view.
func addBottomSheetView() {
// 1- Init bottomSheetVC
let bottomSheetVC = BottomSheetViewController()
// 2- Add bottomSheetVC as a child view
self.addChildViewController(bottomSheetVC)
self.view.addSubview(bottomSheetVC.view)
bottomSheetVC.didMoveToParentViewController(self)
// 3- Adjust bottomSheet frame and initial position.
let height = view.frame.height
let width = view.frame.width
bottomSheetVC.view.frame = CGRectMake(0, self.view.frame.maxY, width, height)
}
And call it in viewDidAppear method:
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
addBottomSheetView()
}
Configure BottomSheetViewController
1) Prepare background
Create a method to add blur and vibrancy effects
func prepareBackgroundView(){
let blurEffect = UIBlurEffect.init(style: .Dark)
let visualEffect = UIVisualEffectView.init(effect: blurEffect)
let bluredView = UIVisualEffectView.init(effect: blurEffect)
bluredView.contentView.addSubview(visualEffect)
visualEffect.frame = UIScreen.mainScreen().bounds
bluredView.frame = UIScreen.mainScreen().bounds
view.insertSubview(bluredView, atIndex: 0)
}
call this method in your viewWillAppear
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
prepareBackgroundView()
}
Make sure that your controller's view background color is clearColor.
2) Animate bottomSheet appearance
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
UIView.animateWithDuration(0.3) { [weak self] in
let frame = self?.view.frame
let yComponent = UIScreen.mainScreen().bounds.height - 200
self?.view.frame = CGRectMake(0, yComponent, frame!.width, frame!.height)
}
}
3) Modify your xib as you want.
4) Add Pan Gesture Recognizer to your view.
In your viewDidLoad method add UIPanGestureRecognizer.
override func viewDidLoad() {
super.viewDidLoad()
let gesture = UIPanGestureRecognizer.init(target: self, action: #selector(BottomSheetViewController.panGesture))
view.addGestureRecognizer(gesture)
}
And implement your gesture behaviour:
func panGesture(recognizer: UIPanGestureRecognizer) {
let translation = recognizer.translationInView(self.view)
let y = self.view.frame.minY
self.view.frame = CGRectMake(0, y + translation.y, view.frame.width, view.frame.height)
recognizer.setTranslation(CGPointZero, inView: self.view)
}
Scrollable Bottom Sheet:
If your custom view is a scroll view or any other view that inherits from, so you have two options:
First:
Design the view with a header view and add the panGesture to the header. (bad user experience).
Second:
1 - Add the panGesture to the bottom sheet view.
2 - Implement the UIGestureRecognizerDelegate and set the panGesture delegate to the controller.
3- Implement shouldRecognizeSimultaneouslyWith delegate function and disable the scrollView isScrollEnabled property in two case:
The view is partially visible.
The view is totally visible, the scrollView contentOffset property is 0 and the user is dragging the view downwards.
Otherwise enable scrolling.
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
let gesture = (gestureRecognizer as! UIPanGestureRecognizer)
let direction = gesture.velocity(in: view).y
let y = view.frame.minY
if (y == fullView && tableView.contentOffset.y == 0 && direction > 0) || (y == partialView) {
tableView.isScrollEnabled = false
} else {
tableView.isScrollEnabled = true
}
return false
}
NOTE
In case you set .allowUserInteraction as an animation option, like in the sample project, so you need to enable scrolling on the animation completion closure if the user is scrolling up.
Sample Project
I created a sample project with more options on this repo which may give you better insights about how to customise the flow.
In the demo, addBottomSheetView() function controls which view should be used as a bottom sheet.
Sample Project Screenshots
- Partial View
- FullView
- Scrollable View
Update iOS 15
In iOS 15, you can now use the native UISheetPresentationController.
if let sheet = viewControllerToPresent.sheetPresentationController {
sheet.detents = [.medium(), .large()]
// your sheet setup
}
present(viewControllerToPresent, animated: true, completion: nil)
Notice that you can even reproduce its navigation stack using the overcurrentcontext presentation mode:
let nextViewControllerToPresent: UIViewController = ...
nextViewControllerToPresent.modalPresentationStyle = .overCurrentContext
viewControllerToPresent.present(nextViewControllerToPresent, animated: true, completion: nil)
Legacy
I released a library based on my answer below.
It mimics the Shortcuts application overlay. See this article for details.
The main component of the library is the OverlayContainerViewController. It defines an area where a view controller can be dragged up and down, hiding or revealing the content underneath it.
let contentController = MapsViewController()
let overlayController = SearchViewController()
let containerController = OverlayContainerViewController()
containerController.delegate = self
containerController.viewControllers = [
contentController,
overlayController
]
window?.rootViewController = containerController
Implement OverlayContainerViewControllerDelegate to specify the number of notches wished:
enum OverlayNotch: Int, CaseIterable {
case minimum, medium, maximum
}
func numberOfNotches(in containerViewController: OverlayContainerViewController) -> Int {
return OverlayNotch.allCases.count
}
func overlayContainerViewController(_ containerViewController: OverlayContainerViewController,
heightForNotchAt index: Int,
availableSpace: CGFloat) -> CGFloat {
switch OverlayNotch.allCases[index] {
case .maximum:
return availableSpace * 3 / 4
case .medium:
return availableSpace / 2
case .minimum:
return availableSpace * 1 / 4
}
}
SwiftUI (12/29/20)
A SwiftUI version of the library is now available.
Color.red.dynamicOverlay(Color.green)
Previous answer
I think there is a significant point that is not treated in the suggested solutions: the transition between the scroll and the translation.
In Maps, as you may have noticed, when the tableView reaches contentOffset.y == 0, the bottom sheet either slides up or goes down.
The point is tricky because we can not simply enable/disable the scroll when our pan gesture begins the translation. It would stop the scroll until a new touch begins. This is the case in most of the proposed solutions here.
Here is my try to implement this motion.
Starting point: Maps App
To start our investigation, let's visualize the view hierarchy of Maps (start Maps on a simulator and select Debug > Attach to process by PID or Name > Maps in Xcode 9).
It doesn't tell how the motion works, but it helped me to understand the logic of it. You can play with the lldb and the view hierarchy debugger.
Our view controller stacks
Let's create a basic version of the Maps ViewController architecture.
We start with a BackgroundViewController (our map view):
class BackgroundViewController: UIViewController {
override func loadView() {
view = MKMapView()
}
}
We put the tableView in a dedicated UIViewController:
class OverlayViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
lazy var tableView = UITableView()
override func loadView() {
view = tableView
tableView.dataSource = self
tableView.delegate = self
}
[...]
}
Now, we need a VC to embed the overlay and manage its translation.
To simplify the problem, we consider that it can translate the overlay from one static point OverlayPosition.maximum to another OverlayPosition.minimum.
For now it only has one public method to animate the position change and it has a transparent view:
enum OverlayPosition {
case maximum, minimum
}
class OverlayContainerViewController: UIViewController {
let overlayViewController: OverlayViewController
var translatedViewHeightContraint = ...
override func loadView() {
view = UIView()
}
func moveOverlay(to position: OverlayPosition) {
[...]
}
}
Finally we need a ViewController to embed the all:
class StackViewController: UIViewController {
private var viewControllers: [UIViewController]
override func viewDidLoad() {
super.viewDidLoad()
viewControllers.forEach { gz_addChild($0, in: view) }
}
}
In our AppDelegate, our startup sequence looks like:
let overlay = OverlayViewController()
let containerViewController = OverlayContainerViewController(overlayViewController: overlay)
let backgroundViewController = BackgroundViewController()
window?.rootViewController = StackViewController(viewControllers: [backgroundViewController, containerViewController])
The difficulty behind the overlay translation
Now, how to translate our overlay?
Most of the proposed solutions use a dedicated pan gesture recognizer, but we actually already have one : the pan gesture of the table view.
Moreover, we need to keep the scroll and the translation synchronised and the UIScrollViewDelegate has all the events we need!
A naive implementation would use a second pan Gesture and try to reset the contentOffset of the table view when the translation occurs:
func panGestureAction(_ recognizer: UIPanGestureRecognizer) {
if isTranslating {
tableView.contentOffset = .zero
}
}
But it does not work. The tableView updates its contentOffset when its own pan gesture recognizer action triggers or when its displayLink callback is called. There is no chance that our recognizer triggers right after those to successfully override the contentOffset.
Our only chance is either to take part of the layout phase (by overriding layoutSubviews of the scroll view calls at each frame of the scroll view) or to respond to the didScroll method of the delegate called each time the contentOffset is modified. Let's try this one.
The translation Implementation
We add a delegate to our OverlayVC to dispatch the scrollview's events to our translation handler, the OverlayContainerViewController :
protocol OverlayViewControllerDelegate: class {
func scrollViewDidScroll(_ scrollView: UIScrollView)
func scrollViewDidStopScrolling(_ scrollView: UIScrollView)
}
class OverlayViewController: UIViewController {
[...]
func scrollViewDidScroll(_ scrollView: UIScrollView) {
delegate?.scrollViewDidScroll(scrollView)
}
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
delegate?.scrollViewDidStopScrolling(scrollView)
}
}
In our container, we keep track of the translation using a enum:
enum OverlayInFlightPosition {
case minimum
case maximum
case progressing
}
The current position calculation looks like :
private var overlayInFlightPosition: OverlayInFlightPosition {
let height = translatedViewHeightContraint.constant
if height == maximumHeight {
return .maximum
} else if height == minimumHeight {
return .minimum
} else {
return .progressing
}
}
We need 3 methods to handle the translation:
The first one tells us if we need to start the translation.
private func shouldTranslateView(following scrollView: UIScrollView) -> Bool {
guard scrollView.isTracking else { return false }
let offset = scrollView.contentOffset.y
switch overlayInFlightPosition {
case .maximum:
return offset < 0
case .minimum:
return offset > 0
case .progressing:
return true
}
}
The second one performs the translation. It uses the translation(in:) method of the scrollView's pan gesture.
private func translateView(following scrollView: UIScrollView) {
scrollView.contentOffset = .zero
let translation = translatedViewTargetHeight - scrollView.panGestureRecognizer.translation(in: view).y
translatedViewHeightContraint.constant = max(
Constant.minimumHeight,
min(translation, Constant.maximumHeight)
)
}
The third one animates the end of the translation when the user releases its finger. We calculate the position using the velocity & the current position of the view.
private func animateTranslationEnd() {
let position: OverlayPosition = // ... calculation based on the current overlay position & velocity
moveOverlay(to: position)
}
Our overlay's delegate implementation simply looks like :
class OverlayContainerViewController: UIViewController {
func scrollViewDidScroll(_ scrollView: UIScrollView) {
guard shouldTranslateView(following: scrollView) else { return }
translateView(following: scrollView)
}
func scrollViewDidStopScrolling(_ scrollView: UIScrollView) {
// prevent scroll animation when the translation animation ends
scrollView.isEnabled = false
scrollView.isEnabled = true
animateTranslationEnd()
}
}
Final problem: dispatching the overlay container's touches
The translation is now pretty efficient. But there is still a final problem: the touches are not delivered to our background view. They are all intercepted by the overlay container's view.
We can not set isUserInteractionEnabled to false because it would also disable the interaction in our table view. The solution is the one used massively in the Maps app, PassThroughView:
class PassThroughView: UIView {
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
let view = super.hitTest(point, with: event)
if view == self {
return nil
}
return view
}
}
It removes itself from the responder chain.
In OverlayContainerViewController:
override func loadView() {
view = PassThroughView()
}
Result
Here is the result:
You can find the code here.
Please if you see any bugs, let me know ! Note that your implementation can of course use a second pan gesture, specially if you add a header in your overlay.
Update 23/08/18
We can replace scrollViewDidEndDragging with
willEndScrollingWithVelocity rather than enabling/disabling the scroll when the user ends dragging:
func scrollView(_ scrollView: UIScrollView,
willEndScrollingWithVelocity velocity: CGPoint,
targetContentOffset: UnsafeMutablePointer<CGPoint>) {
switch overlayInFlightPosition {
case .maximum:
break
case .minimum, .progressing:
targetContentOffset.pointee = .zero
}
animateTranslationEnd(following: scrollView)
}
We can use a spring animation and allow user interaction while animating to make the motion flow better:
func moveOverlay(to position: OverlayPosition,
duration: TimeInterval,
velocity: CGPoint) {
overlayPosition = position
translatedViewHeightContraint.constant = translatedViewTargetHeight
UIView.animate(
withDuration: duration,
delay: 0,
usingSpringWithDamping: velocity.y == 0 ? 1 : 0.6,
initialSpringVelocity: abs(velocity.y),
options: [.allowUserInteraction],
animations: {
self.view.layoutIfNeeded()
}, completion: nil)
}
Try Pulley:
Pulley is an easy to use drawer library meant to imitate the drawer
in iOS 10's Maps app. It exposes a simple API that allows you to use
any UIViewController subclass as the drawer content or the primary
content.
https://github.com/52inc/Pulley
I wrote my own library to achieve the intended behaviour in ios Maps app. It is a protocol oriented solution. So you don't need to inherit any base class instead create a sheet controller and configure as you wish. It also supports inner navigation/presentation with or without UINavigationController.
See below link for more details.
https://github.com/OfTheWolf/UBottomSheet
You can try my answer https://github.com/SCENEE/FloatingPanel. It provides a container view controller to display a "bottom sheet" interface.
It's easy to use and you don't mind any gesture recognizer handling! Also you can track a scroll view's(or the sibling view) in a bottom sheet if needed.
This is a simple example. Please note that you need to prepare a view controller to display your content in a bottom sheet.
import UIKit
import FloatingPanel
class ViewController: UIViewController {
var fpc: FloatingPanelController!
override func viewDidLoad() {
super.viewDidLoad()
fpc = FloatingPanelController()
// Add "bottom sheet" in self.view.
fpc.add(toParent: self)
// Add a view controller to display your contents in "bottom sheet".
let contentVC = ContentViewController()
fpc.set(contentViewController: contentVC)
// Track a scroll view in "bottom sheet" content if needed.
fpc.track(scrollView: contentVC.tableView)
}
...
}
Here is another example code to display a bottom sheet to search a location like Apple Maps.
iOS 15 in 2021 adds UISheetPresentationController, which is Apple's first public release of an Apple Maps-style "bottom sheet":
UISheetPresentationController
UISheetPresentationController lets you present your view controller as a sheet. Before you present your view controller, configure its sheet presentation controller with the behavior and appearance you want for your sheet.
Sheet presentation controllers specify a sheet's size based on a detent, a height where a sheet naturally rests. Detents allow a sheet to resize from one edge of its fully expanded frame while the other three edges remain fixed. You specify the detents that a sheet supports using detents, and monitor its most recently selected detent using selectedDetentIdentifier.
https://developer.apple.com/documentation/uikit/uisheetpresentationcontroller
This new bottom sheet control is explored in WWDC Session 10063: Customize and Resize Sheets in UIKit
Unfortunately....
In iOS 15, the UISheetPresentationController has launched with only medium and large detents.
A small detent is notably absent from the iOS 15 API, which would be required to display an always-presented "collapsed" bottom sheet like Apple Maps:
Custom smaller Detents in UISheetPresentationController?
The medium detent was released to handle use cases such as the Share Sheet or the "••• More" menu in Mail: a button-triggered half sheet.
In iOS 15, Apple Maps is now using this UIKit sheet presentation rather than a custom implementation, which is a huge step in the right direction. Apple Maps in iOS 15 continues to show the "small" bar, as well as a 1/3rd height bar. But those view sizes are not public API available to developers.
UIKit engineers at the WWDC 2021 Labs seemed to know that a small detent would be a hugely popular UIKit component. I would expect to see an API expansion for iOS 16 next year.
We’ve just released a pure Swift Package supporting iOS 11.4+ which provides you a BottomSheet with theme and behavior options you can customize. This component is easy to use, and flexible. You can find it here: https://github.com/LunabeeStudio/LBBottomSheet.
A demo project is available in this repository too.
For example, it supports different ways to manage the needed height, and also adds to the controller behind it the ability to detect height changes and adapt its bottom content inset.
You can find more information on the GitHub repository and in the documentation: https://lbbottomsheet.lunabee.studio.
I think it can help you to do what you’re looking for. Don’t hesitate to tell me if you have comments/questions :)
Here you can see one of all the possible BottomSheet configurations:
**for iOS 15 Native Support available for this **
#IBAction func openSheet() {
let secondVC = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController")
// Create the view controller.
if #available(iOS 15.0, *) {
let formNC = UINavigationController(rootViewController: secondVC!)
formNC.modalPresentationStyle = UIModalPresentationStyle.pageSheet
guard let sheetPresentationController = formNC.presentationController as? UISheetPresentationController else {
return
}
sheetPresentationController.detents = [.medium(), .large()]
sheetPresentationController.prefersGrabberVisible = true
present(formNC, animated: true, completion: nil)
} else {
// Fallback on earlier versions
}
}
iOS 15 finally adds a native UISheetPresentationController!
Official documentation
https://developer.apple.com/documentation/uikit/uisheetpresentationcontroller
I recently created a component called SwipeableView as subclass of UIView, written in Swift 5.1 . It support all 4 direction, has several customisation options and can animate and interpolate different attributes and items ( such as layout constraints, background/tint color, affine transform, alpha channel and view center, all of them demoed with the respective show case ). It also supports the swiping coordination with the inner scroll view if set or auto detected. Should be pretty easy and straightforward to be used ( I hope 🙂)
Link at https://github.com/LucaIaco/SwipeableView
proof of concept:
Hope it helps
If you are looking for a SwiftUI 2.0 solution that uses View Struct, here it is:
https://github.com/kenfai/KavSoft-Tutorials-iOS/tree/main/MapsBottomSheet
Maybe you can try my answer https://github.com/AnYuan/AYPannel, inspired by Pulley. Smooth transition from moving the drawer to scrolling the list. I added a pan gesture on the container scroll view, and set shouldRecognizeSimultaneouslyWithGestureRecognizer to return YES. More detail in my github link above. Wish to help.

ios Changing UIScrollView scrollbar color to different colors

How can we change color of UIScrollview's scroll indicator to something like blue, green etc.
I know we can change it to white, black. But other then these colors.
Many Thanks
Unfortunately you can't, of course you can always roll your own. These are your options:
UIScrollViewIndicatorStyleDefault:
The default style of scroll indicator, which is black with a white border. This style is good against any content background.
UIScrollViewIndicatorStyleBlack:
A style of indicator which is black and smaller than the default style. This style is good against a white content background.
UIScrollViewIndicatorStyleWhite:
A style of indicator is white and smaller than the default style. This style is good against a black content background.
Here's more safe Swift 3 method:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let verticalIndicator = scrollView.subviews.last as? UIImageView
verticalIndicator?.backgroundColor = UIColor.green
}
Both UIScrollView indicator are sub view of UIScrollView. So, we can
access subview of UIScrollView and change the property of subview.
1 .Add UIScrollViewDelegate
#interface ViewController : UIViewController<UIScrollViewDelegate>
#end
2. Add scrollViewDidScroll in implementation section
-(void)scrollViewDidScroll:(UIScrollView *)scrollView1
{
//get refrence of vertical indicator
UIImageView *verticalIndicator = ((UIImageView *)[scrollView.subviews objectAtIndex:(scrollView.subviews.count-1)]);
//set color to vertical indicator
[verticalIndicator setBackgroundColor:[UIColor redColor]];
//get refrence of horizontal indicator
UIImageView *horizontalIndicator = ((UIImageView *)[scrollView.subviews objectAtIndex:(scrollView.subviews.count-2)]);
//set color to horizontal indicator
[horizontalIndicator setBackgroundColor:[UIColor blueColor]];
}
Note:- Because these indicator update every time when you scroll
(means reset to default). SO, we put this code in scrollViewDidScroll
delegate method.
Demo available on GitHub - https://github.com/developerinsider/UIScrollViewIndicatorColor
Based on the answer of #Alex (https://stackoverflow.com/a/58415249/3876285), I'm posting just a little improvement to change the color of scroll indicators.
extension UIScrollView {
var scrollIndicators: (horizontal: UIView?, vertical: UIView?) {
guard self.subviews.count >= 2 else {
return (horizontal: nil, vertical: nil)
}
func viewCanBeScrollIndicator(view: UIView) -> Bool {
let viewClassName = NSStringFromClass(type(of: view))
if viewClassName == "_UIScrollViewScrollIndicator" || viewClassName == "UIImageView" {
return true
}
return false
}
let horizontalScrollViewIndicatorPosition = self.subviews.count - 2
let verticalScrollViewIndicatorPosition = self.subviews.count - 1
var horizontalScrollIndicator: UIView?
var verticalScrollIndicator: UIView?
let viewForHorizontalScrollViewIndicator = self.subviews[horizontalScrollViewIndicatorPosition]
if viewCanBeScrollIndicator(view: viewForHorizontalScrollViewIndicator) {
horizontalScrollIndicator = viewForHorizontalScrollViewIndicator.subviews[0]
}
let viewForVerticalScrollViewIndicator = self.subviews[verticalScrollViewIndicatorPosition]
if viewCanBeScrollIndicator(view: viewForVerticalScrollViewIndicator) {
verticalScrollIndicator = viewForVerticalScrollViewIndicator.subviews[0]
}
return (horizontal: horizontalScrollIndicator, vertical: verticalScrollIndicator)
}
}
If you don't add .subviews[0], you will get the deeper view and when you try to change the color of the indicator, this will appear with a weird white effect. That's because there is another view in front of it:
By adding .subviews[0] to each indicator view, once you try to change the color by calling:
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
DispatchQueue.main.async() {
scrollView.scrollIndicators.vertical?.backgroundColor = UIColor.yourcolor
}
}
You will access to the first view and change the color properly:
Kudos to #Alex who posted a great solution 👍
in IOS 13
Try this one
func scrollViewDidScroll(_ scrollView: UIScrollView){
if #available(iOS 13, *) {
(scrollView.subviews[(scrollView.subviews.count - 1)].subviews[0]).backgroundColor = UIColor.themeColor(1.0) //verticalIndicator
(scrollView.subviews[(scrollView.subviews.count - 2)].subviews[0]).backgroundColor = UIColor.themeColor(1.0) //horizontalIndicator
} else {
if let verticalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 1)] as? UIImageView) {
verticalIndicator.backgroundColor = UIColor.themeColor(1.0)
}
if let horizontalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 2)] as? UIImageView) {
horizontalIndicator.backgroundColor = UIColor.themeColor(1.0)
}
}
}
Swift 2.0 :
Add UIScrollView Delegate.
func scrollViewDidScroll(scrollView: UIScrollView){
let verticalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 1)] as! UIImageView)
verticalIndicator.backgroundColor = UIColor.greenColor()
let horizontalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 2)] as! UIImageView)
horizontalIndicator.backgroundColor = UIColor.blueColor()
}
Try this it would certainly help you
for ( UIView *view in scrollBar.subviews ) {
if (view.tag == 0 && [view isKindOfClass:UIImageView.class])
{
UIImageView *imageView = (UIImageView *)view;
imageView.backgroundColor = [UIColor yellowColor];
}
}
Explanation: UIScrollBar is a collection of subviews. Here scrollBar indicator(vertical/horizontal) is the one of the subviews and it's an UIImageView.So if we set custom color to the UIImageView it effects scrollBar Indicator.
You can change an image of indicator, but you should do this repeadeatly
func scrollViewDidScroll(_ scrollView: UIScrollView) {
self.chageScrollIndicator()
}
func chageScrollIndicator (){
if let indicator = self.collection.subviews.last as? UIImageView {
let edge = UIEdgeInsets(top: 1.25,
left: 0,
bottom: 1.25,
right: 0)
indicator.image = UIImage(named: "ScrollIndicator")?.withRenderingMode(.alwaysTemplate).resizableImage(withCapInsets: edge)
indicator.tintColor = UIConfiguration.textColor
}
}
You can use this 2 image as template:
in IOS 13
Since iOS13 scroll indicators have class _UIScrollViewScrollIndicator, not UIImageView.
Many people used code like
let verticalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 1)] as! UIImageView)
It's not good idea, because they promised that last subview will be UIImageView :). Now it's not and they can get crash.
You can try following code to get scrollView indicators:
extension UIScrollView {
var scrollIndicators: (horizontal: UIView?, vertical: UIView?) {
guard self.subviews.count >= 2 else {
return (horizontal: nil, vertical: nil)
}
func viewCanBeScrollIndicator(view: UIView) -> Bool {
let viewClassName = NSStringFromClass(type(of: view))
if viewClassName == "_UIScrollViewScrollIndicator" || viewClassName == "UIImageView" {
return true
}
return false
}
let horizontalScrollViewIndicatorPosition = self.subviews.count - 2
let verticalScrollViewIndicatorPosition = self.subviews.count - 1
var horizontalScrollIndicator: UIView?
var verticalScrollIndicator: UIView?
let viewForHorizontalScrollViewIndicator = self.subviews[horizontalScrollViewIndicatorPosition]
if viewCanBeScrollIndicator(view: viewForHorizontalScrollViewIndicator) {
horizontalScrollIndicator = viewForHorizontalScrollViewIndicator
}
let viewForVerticalScrollViewIndicator = self.subviews[verticalScrollViewIndicatorPosition]
if viewCanBeScrollIndicator(view: viewForVerticalScrollViewIndicator) {
verticalScrollIndicator = viewForVerticalScrollViewIndicator
}
return (horizontal: horizontalScrollIndicator, vertical: verticalScrollIndicator)
}
}
If you need only one (h or v indicator) - it's better to cut this func and keep only one you need (to improve perfomance).
Also it would be good to call update func inside of DispatchQueue, to keep smoothness of scrolling.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
DispatchQueue.main.async {
scrollView.updateCustomScrollIndicatorView()
}
}
This is how the color of the scroll bar is changed:
//scroll view
UIScrollView *scView = [[UIScrollView alloc] init];
scView.frame = self.view.bounds; //scroll view occupies full parent views
scView.contentSize = CGSizeMake(400, 800);
scView.backgroundColor = [UIColor lightGrayColor];
scView.indicatorStyle = UIScrollViewIndicatorStyleBlack;
scView.showsHorizontalScrollIndicator = NO;
scView.showsVerticalScrollIndicator = YES;
scView.scrollEnabled = YES;
[self.view addSubview: scView];
If you wish to add image as well, here is the code for Swift 3
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let verticalIndicator = scrollView.subviews.last as? UIImageView
verticalIndicator?.image = UIImage(named: "imageName")
}
This works for UITableView and UICollectionView as well.
I wrote an article about this not so far ago. Unfortunately color of this bars defined by pre-defined images, so if you are going to change the color of bars some extra work will be required. Take a look to following link, you will definitely find an answer here since I tried to solve the same issue.
http://leonov.co/2011/04/uiscrollviews-scrollbars-customization/
I ran into the same problem recently so I decided to write a category for it.
https://github.com/stefanceriu/UIScrollView-ScrollerAdditions
[someScrollView setVerticalScrollerTintColor:someColor];
[someScrollView setHorizontalScrollerTintColor:someColor];`
It blends it with the original image so only the color will change. On the other hand, it can also be modified to provide a custom image for the scrollers to use.
Here is what I did in Swift 4, similar to previous answers. In my case I'm recoloring the image to be invisible, set correct corner radius and only execute this process once.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let color = UIColor.red
guard
let verticalIndicator = scrollView.subviews.last as? UIImageView,
verticalIndicator.backgroundColor != color,
verticalIndicator.image?.renderingMode != .alwaysTemplate
else { return }
verticalIndicator.layer.masksToBounds = true
verticalIndicator.layer.cornerRadius = verticalIndicator.frame.width / 2
verticalIndicator.backgroundColor = color
verticalIndicator.image = verticalIndicator.image?.withRenderingMode(.alwaysTemplate)
verticalIndicator.tintColor = .clear
}
please use below code on iOS Renderer
private bool _layouted;
public override void LayoutSubviews()
{
base.LayoutSubviews();
if (!_layouted)
{
this.Layer.BorderColor = UIColor.Red.CGColor;
var Verticalbar = (UIImageView)this.Subviews[this.Subviews.Length - 1];
Verticalbar.BackgroundColor = Color.FromHex("#0099ff").ToUIColor();
var Horizontlebar = (UIImageView)this.Subviews[this.Subviews.Length - 2];
Horizontlebar.BackgroundColor = Color.FromHex("#0099ff").ToUIColor();
_layouted = true;
}
}
As for iOS 13 subviews changed so adding simple if, solved this issues.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 13.0) {
UIView *verticalIndicator = [scrollView.subviews lastObject];
verticalIndicator.backgroundColor = [UIColor redColor];
} else {
UIImageView *verticalIndicator = [scrollView.subviews lastObject];
verticalIndicator.backgroundColor = [UIColor redColor];
}
}
You can use custom UIScrollView scrollBars to implement color in scrollbars. For more details look here

Turn off Zooming in UIScrollView

Does anyone know a way to temporarily turn off zooming when using a UIScrollView?
I see that you can disable scrolling using the following:
self.scrollView.scrollEnabled = false;
but I'm not seeing a similar command for zooming. Any thoughts?
If you want to disable the user's ability to zoom through gestures then in iOS 5 and above you can disable the pinch gesture. This still allows you to control the scroll view from code...
scrollView.pinchGestureRecognizer.enabled = NO;
similarly for pan...
scrollView.panGestureRecognizer.enabled = NO;
This must be called in - (void)viewDidAppear:(BOOL)animated or later as otherwise the system resets it to enabled.
Swift 4.x and above:
imageZoomView.pinchGestureRecognizer?.isEnabled = false / true
Following fbrereto's advice above, I created two functions lockZoom and unlockZoom. When locking Zoom i copied my max and min zoom scales to variables then set the max and min zoom scale to 1.0. Unlocking zoom just reverses the process.
-(void)lockZoom
{
maximumZoomScale = self.scrollView.maximumZoomScale;
minimumZoomScale = self.scrollView.minimumZoomScale;
self.scrollView.maximumZoomScale = 1.0;
self.scrollView.minimumZoomScale = 1.0;
}
-(void)unlockZoom
{
self.scrollView.maximumZoomScale = maximumZoomScale;
self.scrollView.minimumZoomScale = minimumZoomScale;
}
Also you can return "nil" as zooming view in UIScrollViewDelegate:
- (UIView *) viewForZoomingInScrollView:(UIScrollView *) scrollView
{
return canZoom?view:nil;
}
Check setting minimumZoomScale and maximumZoomScale; According to the docs:
maximumZoomScale must be greater than minimumZoomScale for zooming to be enabled.
So, setting the values to be the same should disable zooming.
I have tried setting minimumZoomScale and maximumZoomScale properties of UIScrollView to 1 or isMultipleTouchEnabled property of UIView to false or return nil from viewForZooming(in:) of UIScrollViewDelegate but none worked. In my case, after several trial and error, the following works in my case [Tested on iOS 10.3]:
class MyViewController: UIViewController {
var webView: WKWebView?
override viewDidLoad() {
super.viewDidLoad()
//...
self.webView.scrollView.delegate = self
//...
}
}
extension MyViewController: UIScrollViewDelegate {
func scrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?) {
scrollView.pinchGestureRecognizer?.isEnabled = false
}
}
I know this is a really old question but I made a slight variation for my purposes.
I wanted to be able to easily tell if the zooming was in fact enabled/disabled without relying on a comparison between scrollView.minimumZoomScale == scrollView.maximumZoomScale, which could possibly not reflect whether zooming was actually enabled/disabled.
So I did this
// .h
#property (assign, nonatomic, getter=isZoomEnabled) BOOL zoomEnabled;
// .m
#synthesize zoomEnabled = _zoomEnabled;
- (void)setZoomEnabled:(BOOL)zoomEnabled;
{
_zoomEnabled = zoomEnabled;
UIScrollView *scrollView = self.scrollView;
if (zoomEnabled) {
scrollView.minimumZoomScale = self.minimumZoomScale;
scrollView.maximumZoomScale = self.maximumZoomScale;
} else {
scrollView.minimumZoomScale = 0.0f;
scrollView.maximumZoomScale = 0.0f;
}
}
The values for self.minimumZoomScale and self.maximumZoomScale are set at the time the UIScrollView is configured.
This gives me the ability to set/ask if zooming is enabled.
myViewController.zoomEnabled = YES;
myViewController.isZoomEnabled;
here, my solution for stop zooming on scrollview.
self.scrollView.minimumZoomScale=self.scrollView.maximumZoomScale;
Swift 3 Version:
func lockScrollViewZooming() {
scrollView.minimumZoomScale = 1.0
scrollView.maximumZoomScale = 1.0
scrollView.bounces = false
scrollView.bouncesZoom = false
// Also, if you have double tap recognizer,
// remember to remove it
scrollView.removeGestureRecognizer(doubleTapGestureRecognizer)
}
func unlockScrollViewZooming() {
scrollView.minimumZoomScale = 1.0
scrollView.maximumZoomScale = 4.0
scrollView.bounces = true
scrollView.bouncesZoom = true
// Also, if you have double tap recognizer,
// remember to add it
scrollView.removeGestureRecognizer(doubleTapGestureRecognizer)
}
Note that doubleTapGestureRecognizer should be an instance variable. It should be similar to:
private lazy var doubleTapGestureRecognizer: UITapGestureRecognizer = {
let doubleTapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap(_:)))
doubleTapGestureRecognizer.numberOfTapsRequired = 2
doubleTapGestureRecognizer.delegate = self
return doubleTapGestureRecognizer
}()
#objc private func handleDoubleTap(_ recognizer: UITapGestureRecognizer) {
//scrollView.setZoomScale((scrollView.zoomScale > scrollView.minimumZoomScale) ? scrollView.minimumZoomScale : scrollView.maximumZoomScale, animated: true)
if scrollView.zoomScale > scrollView.minimumZoomScale {
scrollView.setZoomScale(scrollView.minimumZoomScale, animated: true)
} else {
let touchLocation = recognizer.location(in: recognizer.view)
scrollView.zoom(to: CGRect(origin: touchLocation, size: CGSize(width: 22.0, height: 20.0)), animated: true)
}
}
You need to turn off Two Fingers and Double Tap of scroll view
self.scrollView.delegate = self
And
extension YourViewController: UIScrollViewDelegate {
func scrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?) {
scrollView.pinchGestureRecognizer?.isEnabled = false
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return nil
}
}
If you want to disable only zooming with pinch gesture, below code does the trick.
scrollView.pinchGestureRecognizer?.requireGestureRecognizerToFail(scrollView.panGestureRecognizer)

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