I have attached an image here
I am a newbie to iOS development. My question is as follows:
I want to swipe my scrollView outside of its width using gesture control.
To be precise I want my UIScrollView to scroll when swipe is performed in the subview (there is only one subview).
I have gone through several StackOverflow question but I couldn't quite get a correct answer.
Your help is much appreciated!
class ViewController: UIViewController, UIGestureRecognizerDelegate {
#IBOutlet weak var scrollView: UIScrollView!
var images = [UIImageView]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(_ animated: Bool) {
var contentWidth: CGFloat = 0.0
for x in 0...2 {
let image = UIImage(named: "icon\(x).png")
let imageView = UIImageView(image:image)
images.append(imageView)
var newX: CGFloat = 0.0
newX = scrollView.frame.size.width/2 + scrollView.frame.size.width * CGFloat(x)
contentWidth += newX
scrollView.addSubview(imageView)
imageView.frame = CGRect(x: newX - 75, y: (scrollView.frame.size.height/2) - 75, width: 150, height: 150)
}
scrollView.clipsToBounds = false
scrollView.contentSize = CGSize(width: contentWidth, height: view.frame.size.height)
}
As you can see in the image the width of my UIScrollView has a grey background color (I did that to illustrate my point). Now I want to also scroll the scroll view when a user swipes in the subview (non-grey) UIImageView.
I have added the following function and made a return of yes to enable both views to recognize gestures simultaneously. But, I am not getting the desired result. Can anyone take a look?
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
Place view.addGestureRecognizer(scrollView.panGestureRecognizer) in viewDidLoad function.
What it eventually does is it assigns scrollview's gesture recognizer to look for gestures in main view. So it automatically move content of scrollview even when gestures are outside of the scrollview rect.
you can forward touch events in that subview to scrollview. see this answer
Related
I would like to have a horizontal scroll layout which displays images. It works fine if setup 0, 0, 0 and 0 the constraints of the UIScrollView. The problem is exactly when I change the constraints to make margins surrounded the UIScrollView. This is what happens:
First image in the UIScrollView
Second image in the UIScrollView
Third image in the UIScrollView
As you can see, each time you scroll, more off-center the current page is.
I have tried to subtract trailing and leading constrains constants to the width of the scrollLayout, play with frames and bouds but without success.
If I run this example in a smaller display like iphone 5S, the problem is more pointed.
class ViewController: UIViewController, UIScrollViewDelegate {
#IBOutlet weak var pageController: UIPageControl!
#IBOutlet weak var scrollView: UIScrollView!
let imagesArray = ["b_1", "b_2", "b_3", "b_4", "b_5"]
override func viewDidLoad() {
super.viewDidLoad()
self.scrollView.isPagingEnabled = true
self.pageController.numberOfPages = imagesArray.count
self.pageController.pageIndicatorTintColor = UIColor.blue
self.pageController.currentPageIndicatorTintColor = UIColor.gray
for i in 0...imagesArray.count - 1{
let imageView = UIImageView()
imageView.contentMode = .scaleToFill
imageView.image = UIImage(named: self.imagesArray[i])
let xPos = CGFloat(i)*self.view.bounds.size.width
imageView.frame = CGRect(x: xPos, y: 0, width: view.frame.size.width, height: self.scrollView.frame.size.height )
self.scrollView.contentSize.width = view.frame.size.width*CGFloat(i+1)
self.scrollView.addSubview(imageView)
}
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let page = scrollView.contentOffset.x/scrollView.frame.width
self.pageController.currentPage = Int(page)
}
}
So, I would like to know how to always obtain the current image centered.
Thank you
EDITED with Rajesh results and view debug:
I would recommend using a UICollectionView in place of a UIScrollView - otherwise you will be building a lot of the basics from scratch. You can use a collection view that centers the images, make sure paging is enabled and you should get the interface you're looking for. Make sure to adopt / conform to the UICollectionViewDelegate & UICollectionViewDelegateFlowLayout protocols with your view controller & set those delegates on your collection view. Hope that helps! Best of luck.
I have a requirement to support zoom in UICollectionView.
Requirements:
After zoom in, it has to support to view the UICollectionViewCell’s hidden area ( area out of viewport) by horizontal and vertical scroll.
After Zoom out/in, it has to support the selection of UICollectionViewCell and able to scroll the UICollectionView ( Basically the default UICollectionView behavior on going back to no zoom state. ).
The list of approaches tried:
Added GestureRecognizer
a. Added UIPinchGestureRecognizer to transform the UICollectionView by scale.
b. After Zoom in, it was not possible to move the UICollectionViewcell to view the hidden area.
c. Added UIPanGestureRecognizer to move the center of UICollectionView
d. It was working fine to move the UICollectionView.
e. Now we can’t able to select the UICollectionViewCell and can’t able to scroll UICollectionView.
Added UICollectionView inside UIScrollView
a. Added UIScrollView with delegates.
b. Added UICollectionView as sub view of UIScrollView
c. Zoom out is not happening because UICollectionView (inherited by UIScrollView) consumes the zoom gesture
Added UIColectionView and UIScrollView both as siblings
a. Added UIScrollView and UICollectionView to parent.
b. Bring UIScrollView to front.
c. Zoom is working but not able to pan to see the hidden area.
Please suggest if there any way to fix above approaches or a better strategy to achieve zoom in a collectionView.
I have solved this using a UIScrollView and a UICollectionViewLayout subclass.
1) place a UIScrollView on top of the UICollectionView with the same frame.
self.view.addSubview(scrollView)
scrollView.addSubview(dummyViewForZooming)
scrollView.frame = collectionView.frame
scrollView.bouncesZoom = false
scrollView.minimumZoomScale = 0.5
scrollView.maximumZoomScale = 3.0
2) Set the contentSize of the UIScrollView and zoomingView to be the same as the UICollectionView
override func viewDidLayoutSubviews() {
super.viewWillLayoutSubviews()
scrollView.contentSize = layout.collectionViewContentSize
dummyViewForZooming.frame = CGRect(origin: .zero, size: layout.collectionViewContentSize)
scrollView.frame = collectionView.frame
}
3) Remove all gesture recognizers from the UICollectionView and add a delegate for the UIScrollView. Add a tap gesture recognizer to the UIScrollview
collectionView.gestureRecognizers?.forEach {
collectionView.removeGestureRecognizer($0)
}
let tap = UITapGestureRecognizer.init(target: self, action: #selector(scrollViewWasTapped(sender:)))
tap.numberOfTapsRequired = 1
scrollView.addGestureRecognizer(tap)
scrollView.delegate = self
4) When the ScrollView scrolls or zooms, set the contentOffset of the UICollectionView to be the same as the ScrollView contentOffset, set the layoutScale of your UICollectionViewLayout as the zoomscale and invalidate the layout.
func scrollViewDidZoom(_ scrollView: UIScrollView) {
if let layout = self.layout, layout.getScale() != scrollView.zoomScale {
layout.layoutScale = scrollView.zoomScale
self.layout.invalidateLayout()
collectionView.contentOffset = scrollView.contentOffset
}
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return dummyViewForZooming
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
collectionView.contentOffset = scrollView.contentOffset
}
5) override the prepare method in the UICollectionViewLayout, scan through all your layoutAttributes and set a transform:
attribute.transformedFrame = attribute.originalFrame.scale(layoutScale)
let ts = CGAffineTransform(scaleX: layoutScale, y: layoutScale)
attribute.transform = ts
let xDifference = attribute.frame.origin.x - attribute.transformedFrame.origin.x
let yDifference = attribute.frame.origin.y - attribute.transformedFrame.origin.y
let t1 = CGAffineTransform(translationX: -xDifference, y: -yDifference)
let t = ts.concatenating(t1)
attribute.transform = t
6) ensure you scale the collectionView content size:
override var collectionViewContentSize: CGSize {
return CGSize(width: width * layoutScale, height: height * layoutScale)
}
7) Intercept taps from the tap gesture recognizer and convert the location in view to a point in the collection view, you can then get the indexPath of that cell using indexPathForItem(point:) and select the cell or pass on events to the underlying views of the cell etc..
hope this helps
I have two (possibly more) views in a UIScrollView and want to use paging with it. The problem arises when I try to use the default Paging option for UIScrollView, since the views have different widths it can not page properly.
So I have implemented a custom paging code which works. However, when the scrolls are slow, it does not function as expected. (It goes back to the original position without animation.)
Here is how I currently do the custom paging through the UIScrollViewDelegate
func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
if direction == 1{
targetContentOffset.pointee.x = 0
}else{
targetContentOffset.pointee.x = 100
}
}
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
if scrollView.panGestureRecognizer.translation(in: scrollView.superview).x > 0 {
direction = 1
}
else {
direction = 0
}
}
What I want:
What I have:
try to below example for Custom UIScrollView Class
import UIKit
public class BaseScrollViewController: UIViewController, UIScrollViewDelegate {
public var leftVc: UIViewController!
public var middleVc: UIViewController!
public var rightVc: UIViewController!
public var initialContentOffset = CGPoint() // scrollView initial offset
public var maximumWidthFirstView : CGFloat = 0
public var scrollView: UIScrollView!
public class func containerViewWith(_ leftVC: UIViewController,
middleVC: UIViewController,
rightVC: UIViewController) -> BaseScrollViewViewController {
let container = BaseScrollViewViewController()
container.leftVc = leftVC
container.middleVc = middleVC
container.rightVc = rightVC
return container
}
override public func viewDidLoad() {
super.viewDidLoad()
setupHorizontalScrollView()
}
func setupHorizontalScrollView() {
scrollView = UIScrollView()
scrollView.isPagingEnabled = true
scrollView.showsHorizontalScrollIndicator = false
scrollView.bounces = false
let view = (
x: self.view.bounds.origin.x,
y: self.view.bounds.origin.y,
width: self.view.bounds.width,
height: self.view.bounds.height
)
scrollView.frame = CGRect(x: view.x,
y: view.y,
width: view.width,
height: view.height
)
self.view.addSubview(scrollView)
let scrollWidth = 3 * view.width
let scrollHeight = view.height
scrollView.contentSize = CGSize(width: scrollWidth, height: scrollHeight)
leftVc.view.frame = CGRect(x: 0,
y: 0,
width: view.width,
height: view.height
)
middleVc.view.frame = CGRect(x: view.width,
y: 0,
width: view.width,
height: view.height
)
rightVc.view.frame = CGRect(x: 2 * view.width,
y: 0,
width: view.width,
height: view.height
)
addChildViewController(leftVc)
addChildViewController(middleVc)
addChildViewController(rightVc)
scrollView.addSubview(leftVc.view)
scrollView.addSubview(middleVc.view)
scrollView.addSubview(rightVc.view)
leftVc.didMove(toParentViewController: self)
middleVc.didMove(toParentViewController: self)
rightVc.didMove(toParentViewController: self)
scrollView.contentOffset.x = middleVc.view.frame.origin.x
scrollView.delegate = self
}
public func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
self.initialContentOffset = scrollView.contentOffset
}
public func scrollViewDidScroll(_ scrollView: UIScrollView) {
if maximumWidthFirstView != 0
{
if scrollView.contentOffset.x < maximumWidthFirstView
{
scrollView.isScrollEnabled = false
let newOffset = CGPoint(x: maximumWidthFirstView, y: self.initialContentOffset.y)
self.scrollView!.setContentOffset(newOffset, animated: false)
scrollView.isScrollEnabled = true
}
}
}
}
Use of BaseScrollViewController
let left = FirstController.init()
let middle = MiddleController()
let right = RightController.init()
let container = BaseScrollViewController.containerViewWith(left,middleVC: middle,rightVC: right)
container.maximumWidthFirstView = 150
Output:
GitHub gist Example code: https://gist.github.com/mspvirajpatel/58dac2fae0d3b4077a0cb6122def6570
I have previously written a short memo about this problem, and I'll copy/paste it since it is no longer accessible from anywhere. This may not be a specific answer and the codes are pretty old, but I hope this would help you in some degree.
If you have used a paging feature included in UIScrollView, you might also have tempted to customize the width of each page instead of a default, boring, frame width paging. It would be great if you can make the scroll stop at shorter or longer intervals than just multiples of its frame width. Surprisingly, there's no built-in way to configure the width of pages even in our latest iOS7 SDK. There are some ways to achieve custom paging, but none of them I would say are complete. As for now, you'll have to choose either of the following solutions.
1. Change the frame size of your UIScrollView
Alexander Repty has introduced a nice and easy solution to this problem and also included a sample code through his blog: http://blog.proculo.de/archives/180-Paging-enabled-UIScrollView-With-Previews.html
Basically, the instruction can be watered down to the following steps:
Create UIView subclass and override hitTest: withEvent:.
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if ([self pointInside:point withEvent:event]) {
if ([self.subviews count] == 0) return nil;
else return [self.subviews lastObject];
}
return nil;
}
Include UIScrollView as a subview of the above UIView subclass.
Adjust the frame size of your UIScrollView.
Set clipsToBound property of your scroll view to NO.
Set pagingEnabled property of your scroll view to YES.
As you can see, I've just assumed that there is only one subview (the scrollView!) to your UIView subclass. Since you are passing all the touch events occurred in the UIView subclass to your UIScrollView, you'll be able to scroll the content by panning on the UIView subclass, but the paging width will be decided by the width of UIScrollView's frame.
The best part of this approach is that you'll get the genuine feeling and responsiveness, as it is somewhat hard to mimic the paging by using UIScrollView delegate methods.
The only problem I found using this solution is that the width of all pages will have to be identical. You can't set different widths to different pages. If you tries to change your scrollView's frame size dynamically, you'll find there're a number of new emerging problems to deal with. Before trying to fix these glitches, you may want to check out other two solutions using UIScrollView delegates.
2. scrollViewWillEndDragging: withVelocity: targetContentOffset
scrollViewWillEndDragging: withVelocity: targetContentOffset is one of the latest UIScrollView delegate methods(iOS 5.0 or up) that gives you more information than the other old ones.
Since you get the velocity of the scrollView right after you lift the finger up from the screen, we can figure out the direction of the scrolled contents. The last argument, targetContentOffset, not only gives you the expected offset when the scrolling stops eventually, you can also assign CGPoint value in order to let the scrollView scrolls to the desired point.
targetContentOffset = CGPointMake(500, 0);
or
targetContentOffset->x = 500;
However, this will not work as you would think it should because you cannot set the speed of scrolling animation. It feels more like the scrollView happens to stop at the right point rather than it snaps to the spot. I also have to warn you that manually scrolling the contents with setContentOffset: animated: or just by using UIView animation inside the method will not work as expected.
If the velocity is 0, however, you may(and you have to) use manual scrolling to make it snap to the nearest paging point.
It could be the simplest and the most clean approach among all, but the major downside is that it does not provide the same experience that you always had with the real paging feature. To be more honest, it's not even similar to what we call paging. For the better result, we need to combine more delegate methods.
3. Use multiple UIScrollView delegate methods
From my shallow experience, an attempt to scroll your scrollView manually inside any UIScrollView delegate methods will only work when your scrollView has started to decelerate, or when it's not scrolling at all. Therefore, the best place I've found to perform the manual scrolling is scrollViewWillBeginDecelerating:.
Before looking inside the sample code, remember scrollViewEndDragging: withVelocity: targetContentOffset: method will always called prior to scrollViewWillBeginDecelerating:.
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
_scrollVelocity = velocity.x;
if (_scrollVelocity == 0) {
// Find the nearest paging point and scroll.
}
}
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
if (_scrollVelocity < 0) {
[UIView animateWithDuration:0.3 delay:0.0 options:UIViewAnimationOptionCurveEaseOut animations:^{
scrollView.contentOffset = // Previous page offset
} completion:^(BOOL finished){}];
} else if (_scrollVelocity > 0) {
// Animate to the next page offset
}
}
_scrollVelocity is meant to be a global variable or a property, and I've assumed that you have your own ways to decide paging offsets for each page. Note that you'll have to handle the case of zero velocity inside the upper method because the latter method will not be called.
UIView animation with the duration 0.3 and the EaseOut curve option gave me the best result, but of course you should try other combinations to find what's the best for you.
This not the exact solution you might be looking for.
1) Check the offset of the scrollView when it reaches 0, You could show the VIEW you have above , You could animate while checking the scrollview movement so that it looks nice .But not completely
2) Now the VIEW is partially above your camera(you can decrease it alpha so that scrollview is still visible).
3) user can tap the view and you can show it completely.
You may want to consider calculating the most visible cell in your collection view after dragging ends and then programmatically scroll to – and center – that cell.
So something like:
First, implement the scrollViewDidEndDragging(_:willDecelerate:) method of your collection view's delegate. Then, in that method's body, determine which cell in collectionView.visibleCells is most visible by comparing each of their centers against your collection view's center. Once you find your collection view's most visible cell, scroll to it by calling scrollToItem(at:at:animated:).
I have created two UIScrollViews ( One named scrollView and one named scrollLevel4 )
when I move scrollLevel4, I can get scrollView to move at the same speed using :-
func scrollViewDidScroll(_ scrollLevel4: UIScrollView) {
scrollView.contentOffset.x = scrollLevel4.contentOffset.x
}
However If I want to move scrollView at a different pace, not sure what to do, whenever I add anything to the end of line :
scrollView.contentOffset.x = scrollLevel4.contentOffset.x
it crashes, even a simple + 10, same pace, staggered offset, still crashes
also tried .scrollRectToVisible() method
Thoughts ?
Without seeing the error or your code it's hard to say for sure, but most likely you are setting the same delegate for both scrollViews. When you drag scrollLevel4, it triggers a scroll on scrollView, so you get an infinite loop and eventually a crash.
If you want to use the same delegate on both scrollViews, you'll need to check which one was passed before operating on them. Here's a basic working implementation. Open a new single view project and replace the code in ViewController.swift with:
import UIKit
class ViewController: UIViewController, UIScrollViewDelegate {
var imageView1: UIImageView!
var imageView2: UIImageView!
var scrollView1: UIScrollView!
var scrollView2: UIScrollView!
override func viewDidLoad() {
super.viewDidLoad()
imageView1 = UIImageView(image: UIImage(named: "image.jpg"))
imageView2 = UIImageView(image: UIImage(named: "image.jpg"))
scrollView1 = UIScrollView(frame: CGRect(origin: CGPoint.zero, size: CGSize(width: 200, height: 200)))
scrollView1.contentSize = imageView1.bounds.size
scrollView1.addSubview(imageView1)
view.addSubview(scrollView1)
scrollView2 = UIScrollView(frame: CGRect(origin: CGPoint(x: 0, y: 210), size: CGSize(width: 200, height: 200)))
scrollView2.contentSize = imageView2.bounds.size
scrollView2.addSubview(imageView2)
view.addSubview(scrollView2)
scrollView2.delegate = self
scrollView1.delegate = self
}
func scrollViewDidScroll(_ scrolled: UIScrollView) {
// both scrollViews call this when scrolled, so determine which was scrolled before adjusting
if scrolled === scrollView1 {
scrollView2.contentOffset.x = scrolled.contentOffset.x + 100
} else if scrolled === scrollView2 {
scrollView1.contentOffset.x = scrolled.contentOffset.x - 100
}
}
}
Note that whatever modification you apply to the offset of one, you have to apply the exact inverse (or nothing at all) to the other. Otherwise you'll have an infinite loop of back and forth scrolling ending in a crash.
On Facebook Messenger for iOS, it has it so if the keyboard is hidden, if you swipe up, the keyboard will show. It does this exactly in reverse to the interactive keyboard dismissal mode: the keyboard reveals itself as you swipe up at the speed in which you swipe up.
Does anybody have any pointers on how to do this?
Edit: thanks for the answers! I was mostly looking into whether there was a built-in way to do this, since I saw it being done in Facebook Messenger. However, I just read a blog post where they said they had to screenshot the system keyboard to get the effect—so I’ll assume there’s no built-in way to do this! As mentioned in the comments, I’m using a custom keyboard, so this should be a lot easier, since I have control over the frame!
Basically you'll need UIPanGestureRecognizer.
Set UIScreenEdgePanGestureRecognizer for bottom edge, UIPanGestureRecognizer for hiding the keyboard in Storyboard and drag #IBAction outlets to the code.
Set you keyboard view container with your keyboard in the bottom of the controller in Storyboard, so that user doesn't see it. Drag an #IBOutlet to your code so that you'll be able to modify it's frame.
In gesture actions when dragging your animate the view movement.
When stopped dragging you need to check the view's position and animate it to the destination if it's not there yet.
Also you'll need to add a check for the dragging area so that user cannot drag it further.
It's simple, you'll just need to check all cases and test it properly.
This is a basic setup you can build from this:
class ViewController: UIViewController {
#IBOutlet weak var keyboardContainerView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func onEdgePanGestureDrag(_ sender: UIScreenEdgePanGestureRecognizer) {
let point = sender.location(in: view)
view.layoutIfNeeded()
UIView.animate(withDuration: 0.33) {
// Animate your custom keyboard view's position
self.keyboardContainerView.frame = CGRect(x: self.keyboardContainerView.bounds.origin.x,
y: point.y,
width: self.keyboardContainerView.bounds.width,
height: self.keyboardContainerView.bounds.height)
}
view.layoutIfNeeded()
}
#IBAction func onPanGestureDrag(_ sender: UIPanGestureRecognizer) {
let point = sender.location(in: view)
view.layoutIfNeeded()
UIView.animate(withDuration: 0.33) {
// Animate your custom keyboard view's position
self.keyboardContainerView.frame = CGRect(x: self.keyboardContainerView.bounds.origin.x,
y: point.y,
width: self.keyboardContainerView.bounds.width,
height: self.keyboardContainerView.bounds.height)
}
view.layoutIfNeeded()
}
}
Here is an implementation that worked for me. It's not perfect but it works fairly well and is simple to implement.You will need a collection view or a table view.
For the sake of simplicity I will only show code that is necessary for this feature. so please handle everything else that is necessary for the views' initialization.
class ViewController: UIViewController {
var collectionView: UICollectionView!
var textView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
collectionView.panGestureRecognizer.addTarget(self, action: #selector(handlePan(_:)))
collectionView.keyboardDismissMode = .interactive
// Only necessary for empty collectionView
collectionView.alwaysBounceVertical = true
}
func handlePan(_ sender: UIPanGestureRecognizer) {
if sender.state == .changed {
let translation = sender.translation(in: view)
if translation.y < 0 && collectionView.isAtBottom && !self.textView.isFirstResponder() {
self.textView.becomeFirstResponder()
}
}
}
}
extension UIScrollView {
var isAtBottom: Bool {
return contentOffset.y >= verticalOffsetForBottom
}
var verticalOffsetForBottom: CGFloat {
let scrollViewHeight = bounds.height
let scrollContentSizeHeight = contentSize.height
let bottomInset = contentInset.bottom
let scrollViewBottomOffset = scrollContentSizeHeight + bottomInset - scrollViewHeight
return scrollViewBottomOffset
}
}