I am using SFSpeechRecognizer to transcribe audio to text. As the audio is transcribed, I am printing it out as results come out to a uilabel, which is a subview of a uiscrollview. The uilabel is pinned to the top and bottom of the uiscrollview.
My problem is programmatically scrolling the uiscrollview to the bottom as the uilabel grows in height from the transcription.
I tried solutions such as this but it does not work. Any guidance would be much appreciated.
Code I've tried:
SFSpeechRecognizer().recognitionTask(with: request) { [unowned self] (result, error) in
guard let result = result else {
DispatchQueue.main.async {
self.transcriptionLabel.text = "We're not able to transcribe."
}
return
}
DispatchQueue.main.async {
self.transcriptionLabel.text = result.bestTranscription.formattedString
if self.transcriptionScrollView.contentSize.height - self.transcriptionScrollView.bounds.size.height > 0 {
let bottomOffset = CGPoint(x: 0, y: self.transcriptionScrollView.contentSize.height - self.transcriptionScrollView.bounds.height + self.transcriptionScrollView.contentInset.bottom)
self.transcriptionScrollView.setContentOffset(bottomOffset, animated: true)
}
self.view.layoutIfNeeded()
}
}
Again, the first thing you need to do is layout your subviews after updating the text so your computations are based on the new text.
Rather than jumping through a lot of hoops and trying to compute the contentOffset I would suggest using scrollToRectVisible(_:animated:).
view.layoutIfNeeded()
let rect = CGRect(
x: 0,
y: transcriptionLabel.frame.maxY - 1,
width: 1,
height: 1)
transcriptionScrollView.scrollRectToVisible(rect, animated: true)
That should scroll you to the bottom of the label, assuming that your label is a subview of your scrollView. If not, you will need to convert the label's frame to the scrollView coordinate space.
Remember to call view.layoutIfNeeded() after updating the text in your label and before scrolling.
Related
My situation:
I have a horizontal ScrollView containing a StackView.
Inside this StackView there are some Views, that can be expanded/collapsed.
When I want to expand one of these Views, I first unhide some subViews in the View. After that I need to change the height of the ScrollView based on the new height of this View.
But this is not working...
I try this code:
UIView.animate(withDuration: 0.3) { [self] in
// Toggle hight of all subViews
stackView.arrangedSubviews.forEach { itemView in
guard let itemView = itemView as? MyView else { return }
itemView.toggleView()
}
// Now update the hight of the StackView
// But here the hight is always from the previous toggle
let height = self.stackView.arrangedSubviews.map {$0.frame.size.height}.max() ?? 0.0
print(height)
heightConstraint.constant = height
}
This code nicely animates, but always to the wrong height.
So the ScrollView animates to collapsed when it should be expanded and expanded when it should be collapsed.
Anyone with on idea how to solve this?
The problem is that, whatever you are doing here:
itemView.toggleView()
may have done something to change the height a view, but then you immediately call:
let height = self.stackView.arrangedSubviews.map {$0.frame.size.height}.max() ?? 0.0
before UIKit has updated the frames.
So, you can either track your own height property, or...
get the frame heights after the update - such as with:
DispatchQueue.main.async {
let height = self.stackView.arrangedSubviews.map {$0.frame.size.height}.max() ?? 0.0
print("h", height)
self.scrollHeightConstraint.constant = height
UIView.animate(withDuration: 0.3) {
self.view.layoutIfNeeded()
}
}
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 am trying ot troubleshoot a tableView header (pink) that is animating a collapse. As the tableViewHeader height is shrinking the table view cells should pull up with the top of their tableView (orange). The beginning and end states are correct, but somehow the table view cells are animating up at a different rate. Something is clearly wrong here, I just can't seem to pinpoint what it is.
It appears to have something to do with the fact that I am using self sizing table view cells and tableView.rowHeight = UITableViewAutomaticDimension. If I use fixed height cells everything is fine.
Beginning State:
Middle State (Note cells already sliding under header):
Final State (Final state of layout is correct):
Here is the code that animates the collapse.
func collapseHeader() {
UIView.animate(withDuration: 0.25, delay: 0, options: .curveEaseIn, animations: {
self.tableView.beginUpdates()
if let header = self.tableView.tableHeaderView as? TopicTableHeaderView {
header.setHeaderState(state: .collapsed)
}
self.sizeHeaderToFit()
self.view.layoutIfNeeded()
self.tableView.endUpdates()
}) { (bool) in
print("collapse completed")
}
}
func sizeHeaderToFit() {
if let headerView = tableView.tableHeaderView {
let height = headerView.systemLayoutSizeFitting(UILayoutFittingCompressedSize).height
var frame = headerView.frame
frame.size.height = height
if headerView.frame.height != height {
headerView.frame = frame
tableView.tableHeaderView = headerView
headerView.setNeedsLayout()
headerView.layoutIfNeeded()
}
}
}
And the problem was simply where I was calling self.tableView.beginUpdates(). I moved that to the line directly above self.tableView.endUpdates() and that solved the problem.
I'm trying to implement a view very similar to Evernote's screen in which you add a New Note.
It seems like a UITableView embedded in a NavigationController. This tableview contains static cells (2 or 3) with the bottom one being a UITextView in which you add the content of the note, but when you scroll on the textView, the other cells that contain a textField and another control.
How can this be achieved? I know that Apple doesn't recommend a TextView inside a ScrollView, and doing it with table view it gets a bit weird with all the scrolling from the table and text view.
Here are some examples:
Any suggestions?
Thank you!
Firstly, They disabled text view scrolling and set its size to about screen size. Secondly, once text view's text is out of frame, expand it(calculate its size again).
So I found my problem, when I was setting the constraints for the content view (view inside scrollview) I set an Equal value for its height. To fix it I just made that relationship to Greater or Equal than... it now expands.
The other problem now is that when showing the keyboard it is not scrolling to the text I tap to. (The insets are properly setup though)
// MARK: Notififations from the Keyboard
func didShowKeyboard (notification: NSNotification) {
if momentTextView.isFirstResponder() {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
scrollView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.size.height, right: 0)
scrollView.scrollIndicatorInsets = scrollView.contentInset
let caretPosition = momentTextView.caretRectForPosition(momentTextView.selectedTextRange!.start)
let newHeight = caretPosition.height * 1.5
let newCaretPosition = CGRect(x: caretPosition.origin.x, y: caretPosition.origin.y, width: caretPosition.width, height: newHeight)
scrollView.scrollRectToVisible(newCaretPosition, animated: true)
}
}
}
func willHideKeyboard (notification: NSNotification) {
if momentTextView.isFirstResponder() {
scrollView.contentInset = UIEdgeInsetsZero
scrollView.scrollIndicatorInsets = UIEdgeInsetsZero
}
}
How do I make a UIScrollView scroll to the top?
UPDATE FOR iOS 7
[self.scrollView setContentOffset:
CGPointMake(0, -self.scrollView.contentInset.top) animated:YES];
ORIGINAL
[self.scrollView setContentOffset:CGPointZero animated:YES];
or if you want to preserve the horizontal scroll position and just reset the vertical position:
[self.scrollView setContentOffset:CGPointMake(self.scrollView.contentOffset.x, 0)
animated:YES];
Here is a Swift extension that makes it easy:
extension UIScrollView {
func scrollToTop() {
let desiredOffset = CGPoint(x: 0, y: -contentInset.top)
setContentOffset(desiredOffset, animated: true)
}
}
Usage:
myScrollView.scrollToTop()
For Swift 4
scrollView.setContentOffset(.zero, animated: true)
iOS 11 and above
Try to play around with the new adjustedContentInset (It should even work with prefersLargeTitles, safe area etc.)
For example (scroll to the top):
var offset = CGPoint(
x: -scrollView.contentInset.left,
y: -scrollView.contentInset.top)
if #available(iOS 11.0, *) {
offset = CGPoint(
x: -scrollView.adjustedContentInset.left,
y: -scrollView.adjustedContentInset.top)
}
scrollView.setContentOffset(offset, animated: true)
Use setContentOffset:animated:
[scrollView setContentOffset:CGPointZero animated:YES];
Answer for Swift 2.0/3.0/4.0 and iOS 7+:
let desiredOffset = CGPoint(x: 0, y: -self.scrollView.contentInset.top)
self.scrollView.setContentOffset(desiredOffset, animated: true)
In iOS7 I had trouble getting a particular scrollview to go to the top, which worked in iOS6, and used this to set the scrollview to go to the top.
[self.myScroller scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:NO];
In SWIFT 5
Just set content Offset to zero
scrollView.setContentOffset(CGPoint.zero, animated: true)
Swift 3.0.1 version of rob mayoff's answer :
self.scrollView.setContentOffset(
CGPoint(x: 0,y: -self.scrollView.contentInset.top),
animated: true)
I think I have an answer that should be fully compatible with iOS 11 as well as prior versions (for vertical scrolling)
This takes into account the new adjustedContentInset and also accounts for the additional offset required when prefersLargeTitles is enabled on the navigationBar which appears to require an extra 52px offset on top of whatever the default is
This was a little tricky because the adjustedContentInset changes depending on the titleBar state (large title vs small title) so I needed to check and see what the titleBar height was and not apply the 52px offset if its already in the large state. Couldn't find any other method to check the state of the navigationBar so if anyone has a better option than seeing if the height is > 44.0 I'd like to hear it
func scrollToTop(_ scrollView: UIScrollView, animated: Bool = true) {
if #available(iOS 11.0, *) {
let expandedBar = (navigationController?.navigationBar.frame.height ?? 64.0 > 44.0)
let largeTitles = (navigationController?.navigationBar.prefersLargeTitles) ?? false
let offset: CGFloat = (largeTitles && !expandedBar) ? 52: 0
scrollView.setContentOffset(CGPoint(x: 0, y: -(scrollView.adjustedContentInset.top + offset)), animated: animated)
} else {
scrollView.setContentOffset(CGPoint(x: 0, y: -scrollView.contentInset.top), animated: animated)
}
}
Inspired by Jakub's solution
It's very common when your navigation bar overlaps the small portion of the scrollView content and it looks like content starts not from the top. For fixing it I did 2 things:
Size Inspector - Scroll View - Content Insets --> Change from Automatic to Never.
Size Inspector - Constraints- "Align Top to" (Top Alignment Constraints)- Second item --> Change from Superview.Top to Safe Area.Top and the value(constant field) set to 0
To fully replicate the status bar scrollToTop behavior we not only have to set the contentOffset but also want to make sure the scrollIndicators are displayed. Otherwise the user can quickly get lost.
The only public method to accomplish this is flashScrollIndicators. Unfortunately, calling it once after setting the contentOffset has no effect because it's reset immediately. I found it works when doing the flash each time in scrollViewDidScroll:.
// define arbitrary tag number in a global constants or in the .pch file
#define SCROLLVIEW_IS_SCROLLING_TO_TOP_TAG 19291
- (void)scrollContentToTop {
[self.scrollView setContentOffset:CGPointMake(self.scrollView.contentOffset.x, -self.scrollView.contentInset.top) animated:YES];
self.scrollView.tag = SCROLLVIEW_IS_SCROLLING_TO_TOP_TAG;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
self.scrollView.tag = 0;
});
}
In your UIScrollViewDelegate (or UITable/UICollectionViewDelegate) implement this:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if (scrollView.tag == SCROLLVIEW_IS_SCROLLING_TO_TOP_TAG) {
[scrollView flashScrollIndicators];
}
}
The hide delay is a bit shorter compared to the status bar scrollToTop behavior but it still looks nice.
Note that I'm abusing the view tag to communicate the "isScrollingToTop" state because I need this across view controllers. If you're using tags for something else you might want to replace this with an iVar or a property.
In modern iOS, set the the scroll view's content offset back to its top left adjustedContentInset:
let point = CGPoint(x: -scrollView.adjustedContentInset.left,
y: -scrollView.adjustedContentInset.top)
scrollView.setContentOffset(point, animated: true)
Scroll to top for UITableViewController, UICollectionViewController or any UIViewController having UIScrollView
extension UIViewController {
func scrollToTop(animated: Bool) {
if let tv = self as? UITableViewController {
tv.tableView.setContentOffset(CGPoint.zero, animated: animated)
} else if let cv = self as? UICollectionViewController{
cv.collectionView?.setContentOffset(CGPoint.zero, animated: animated)
} else {
for v in view.subviews {
if let sv = v as? UIScrollView {
sv.setContentOffset(CGPoint.zero, animated: animated)
}
}
}
}
}
iOS 16
For table and collection views, the following always works for me:
let top = CGRect(x: 0, y: 0, width: 1, height: 1)
tableView.scrollRectToVisible(top, animated: true)
collectionView.scrollRectToVisible(top, animated: true)
For scroll views:
let top = CGPoint(x: 0, y: -adjustedContentInset.top)
scrollView.setContentOffset(top, animated: animated)
adjustedContentInset returns the insets applied by the safe area (if any) and any custom insets applied after instantiation. If either safe or custom insets are applied, the content inset of the scroll view when it's at its top will be negative, not zero, which is why this property should be used.
iOS 2.0+
Mac Catalyst 13.0+
You can try: scrollView.scrollsToTop = true
You can refer it from documentation of developer.apple.com
I tried all the ways. But nothing worked for me. Finally I did like this.
I added self.view .addSubview(self.scroll) line of code in the viewDidLoad. After started setting up frame for scroll view and added components to scroll view.
It worked for me.
Make sure you added self.view .addSubview(self.scroll) line in the beginning. then you can add UI elements.