How can I set UITextView selectedTextRange with animation and scroll position - ios

I've been trying to figure out a way to set the cursor to the bottom of a long UITextView with animation. Setting it wasn't too difficult, in fact this answer covers it very well. https://stackoverflow.com/a/34922332/563381
However, animating it isn't so easy. There isn't a setSelectedTextRange(animated:) that I can find. Setting it inside a UIView.animate... block doesn't seem to do anything. The best I've been able to come up with is to animate the scroll manually then in the completion set the selectedTextRange. However this is fragile, often looks choppy, and seems on occasion to not work at all.
When you set selectedTextRange it does jump to that location. If there was a way to avoid that jump the animation might be smoother and at least would be less fragile since it wouldn't require a delay and you could use setContentOffset(animated) without needing to wait to set the selectedTextRange.
The other option is to find a way to cause the selectedTextRange jump to be animated itself. On this front I tried the trick of disabling scrolling before and reenabling after but that didn't seem to work for me. Guessing that has changed in later versions of iOS.

You can use setContentOffset(_, animated:) and detect the end of the animation with scrollViewDidEndScrollingAnimation and set the cursor like so:
// The action to scroll down
#IBAction func test(_ sender: Any) {
let offset = self.textView.contentSize.height - self.textView.frame.height
self.textView.setContentOffset(CGPoint(x: 0, y: offset), animated: true)
}
// Setting the cursor down
func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
let offset = self.textView.contentSize.height - self.textView.frame.height
if scrollView.contentOffset == CGPoint(x: 0, y: offset) {
let newPosition = textView.endOfDocument
self.textView.selectedTextRange = self.textView.textRange(from: newPosition, to: newPosition)
}
}
You will need to add UITextViewDelegate to your view controller and set the textView delegate:
textView.delegate = self

Related

Change CollectionView position with animation but move back when first scroll

I want to change my collectionView position when pressing a button. I wrapped the collectionView and Button in a View and used UIView animate to make it move up. It can move up successfully, but when I am scrolling collectionView it's return back to its original position. If I tried many times, it became normal and didn't move back again.
How could i fix this issue? Thank you for any advice.
func openPreview() {
if !isPreviewOpened {
UIView.animate(withDuration: 0.3) {
self.previewView.frame.origin.y -= self.previewView.frame.height
self.previewButton.frame.origin.y -= self.previewView.frame.height
}
isPreviewOpened = true
updateUI()
}
func closePreview() {
if isPreviewOpened {
UIView.animate(withDuration: 0.3) {
self.previewView.frame.origin.y += self.previewView.frame.height
self.previewButton.frame.origin.y += self.previewView.frame.height
}
isPreviewOpened = false
updateUI()
}
}
After asking others, provide my solution to this question, hope it can help someone in the future.
This issue was happened because that the frame I changed conflicting with the auto layout I set earlier in storyboard. According to the document, I have to set translatesAutoresizingMaskIntoConstraints to true to track the frames.
By default, the autoresizing mask on a view gives rise to constraints that fully determine
the view's position. This allows the auto layout system to track the frames of views whose
layout is controlled manually (through -setFrame:, for example).
When you elect to position the view using auto layout by adding your own constraints,
you must set this property to NO. IB will do this for you.
So this is the answer.
func openPreview() {
if !isPreviewOpened {
previewView.translatesAutoresizingMaskIntoConstraints = true
UIView.animate(withDuration: 0.3) {
self.previewView.frame.origin.y = self.view.bounds.maxY - self.previewView.frame.height
self.previewButton.frame.origin.y = self.view.bounds.maxY - self.previewView.frame.height - self.previewButton.frame.height
}
}
}

Smooth custom paging for UIScrollView

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:).

UITableView contentInset not updating when keyboard interactively dismissed

Update
I found that in my many refactorings I was inheriting from UIViewController instead of UITableViewController, so I was missing some automatic behaviours that UITableViewController provides. However, I still needed to manually handle the scroll views insets when the keyboard was being interactively dismissed. See my updated answer.
I am trying to emulate iMessage in how the keyboard is dismissed when the user drags it to the bottom of the screen. I have it working with one small visual issue that's bugging me.
As the keyboard is dragged off the screen the scroll indicators do not resize correctly - that is until it has been completely dismissed.
I use keyboard notifications to tell me when the keyboard has appeared to increase the content and scroll insets by the height of the keyboard. It seems I didn't need to do anything when the keyboard has been dismissed as the insets appear to be correct when it has been. However when dismissing interactively I can't update the insets during the dragging event.
To illustrate the issue, the first image shows that content has scrolled off the top of the screen due to the space being occupied by the keyboard; the user has scrolled to the last row in the table:
Here, the keyboard is being dismissed and is almost completely off-screen. However notice how the scroll indicators are completely the wrong size. All of the content is now almost on screen so the indicators should be stretching, however, what happens is that as the keyboard moves down, the scroll indicators move up and do not stretch. This is not what happens in iMessage.
I think what I'm doing is pretty standard, I'm creating a UIToolBar (iOS 8.3) and overriding these methods in my view controller:
override var inputAccessoryView: UIView {
return toolbar
}
override func canBecomeFirstResponder() -> Bool {
return true
}
func willShowKeyboard(notification: NSNotification) {
let keyboardFrame = notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue
tableView.contentInset.bottom = keyboardFrame.CGRectValue().height
tableView.scrollIndicatorInsets.bottom = keyboardFrame.CGRectValue().height
}
Update
After switching to a UITableViewController, I found that this implementation of scrollViewDidScroll() (along with the other methods in the original solution below) did the trick of dynamically resizing the insets when the keyboard was interactively dismissed.
override func scrollViewDidScroll(scrollView: UIScrollView) {
if !keyboardShowing {
return
}
let toolbarFrame = toolbar.convertRect(toolbar.frame, toView: nil)
tableView.scrollIndicatorInsets.bottom = view.bounds.height - toolbarFrame.minY
tableView.contentInset.bottom = view.bounds.height - toolbarFrame.minY
}
I've managed to achieve the same effect. I'm not sure if this is the correct method, but it works nicely. I'll be interested to know what other solutions there might be.
func didShowKeyboard(notification: NSNotification) {
let keyboardFrame = notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue
let keyboardHeight = keyboardFrame.CGRectValue().height
tableView.contentInset.bottom = keyboardHeight
tableView.scrollIndicatorInsets.bottom = keyboardHeight
keyboardShowing = true
}
func didHideKeyboard(notification: NSNotification) {
keyboardShowing = false
}
func scrollViewDidScroll(scrollView: UIScrollView) {
if !keyboardShowing {
return
}
let toolbarFrame = view.convertRect(toolbar.frame, fromView: toolbar)
tableView.scrollIndicatorInsets.bottom = view.bounds.height - toolbarFrame.minY
tableView.contentInset.bottom = view.bounds.height - toolbarFrame.minY
}

UITextView starts at Bottom or Middle of the text

I'll get right to it. I have a UItextView placed in my view that when needs to scroll to see all the text (when a lot of text is present in the textView) the textView starts in the middle of the text sometimes and the bottom of the text other times.
Editing is not enabled on the textView. I need a way to force the textView to start at the top, every time. I saw some questions somewhat like this where other people used a content offset, but I do not really know how that works or if it would even be applicable here.
Thanks for your help.
That did the trick for me!
Objective C:
[self.textView scrollRangeToVisible:NSMakeRange(0, 0)];
Swift:
self.textView.scrollRangeToVisible(NSMakeRange(0, 0))
Swift 2 (Alternate Solution)
Add this override method to your ViewController
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
textView.setContentOffset(CGPointZero, animated: false)
}
Swift 3 & 4 (syntax edit)
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
textView.contentOffset = .zero
}
All of the answers above did not work for me. However, the secret turns out to be to implement your solution within an override of viewDidLayoutSubviews, as in:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
welcomeText.contentOffset = .zero
}
HTH :)
In Swift 2
You can use this to make the textView start from the top:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
myTextView.setContentOffset(CGPointZero, animated: false)
}
Confirmed working in Xcode 7.2 with Swift 2
Try this below code -
if ( [self respondsToSelector:#selector(setAutomaticallyAdjustsScrollViewInsets:)]){
self.automaticallyAdjustsScrollViewInsets = NO;
}
Or you can also set this property by StoryBoard -
Select ViewController then select attributes inspector now unchecked Adjust Scroll View Insets.
For Swift >2.2, I had issues with iOS 8 and iOS 9 using above methods as there are no single answer that works so here is what I did to make it work for both.
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
if #available(iOS 9.0, *) {
textView.scrollEnabled = false
}
self.textView.scrollRangeToVisible(NSMakeRange(0, 0))
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
if #available(iOS 9.0, *) {
textView.scrollEnabled = true
}
}
Update your UINavigationBar's translucent property to NO:
self.navigationController.navigationBar.translucent = NO;
This will fix the view from being framed underneath the navigation bar and status bar.
If you have to show and hide the navigation bar, then use below code in your viewDidLoad
if ([self respondsToSelector:#selector(edgesForExtendedLayout)])
self.edgesForExtendedLayout = UIRectEdgeNone; // iOS 7 specific
Hope this helps.
Xcode 7.2 7c68; IOS 9.1
My ViewController which contains UITextView is complicated, and changed a lot during the project (IDE version changed maybe 2~3 times too).
I've tried all above solutions, if you encounter the same issue, be PATIENT.
There are three possible 'secret codes' to solve:
textView.scrollEnabled = false
//then set text
textView.scrollEnabled = true
textView.scrollRangeToVisible(NSMakeRange(0, 0))
textView.setContentOffset(CGPointZero, animated: false)
And there are two places you can put those codes in:
viewDidLoad()
viewDidLayoutSubviews()
Combine them, you'll get 3*2=6 solutions, the correct combination depends on how complicated you ViewController is (Believe me, after delete just a view above textView, I need to find a new combination).
And I found that:
When put 'secret codes' in viewDidLayoutSubviews(), but textView.text = someStrings in viewDidLoad(), the content in textView will 'shake' sometimes. So, put them in the same place.
Last word: try ALL combinations, this is how I solve this stupid bug more than three times during two months.
With a lot of testing, i found must add below in viewWillLayoutSubviews() function to make sure the UITextView show up from the very beginning:
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
textViewTerms.scrollRangeToVisible(NSMakeRange(0, 0))
}
UITextView scrolling seems to be a problem to a lot of people. Gathering from the answers here around (especially this) and the Apple Developer documentation, using some of my own wit, here is a solution that works for me. You can modify the code to suit your needs.
My use case is as follows: the same UITextView is used for different purposes, displaying varying content in different circumstances. What I want is that when the content changes, the old scroll position is restored, or at times, scrolled to the end. I don't want too much animation when this is done. Especially I don't want the view to animate like all the text was new. This solution first restores the old scroll position without animation, then scrolls to the end animated, if so desired.
What you need to do (or should I say can do) is extend UITextView as follows:
extension UITextView {
func setText(text: String, storedOffset: CGPoint, scrollToEnd: Bool) {
self.text = text
let delayInSeconds = 0.001
let popTime: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, Int64(delayInSeconds * Double(NSEC_PER_SEC)))
dispatch_after(popTime, dispatch_get_main_queue(), {
self.setContentOffset(storedOffset, animated: false)
if scrollToEnd && !text.isEmpty {
let popTime: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, Int64(delayInSeconds * Double(NSEC_PER_SEC)))
dispatch_after(popTime, dispatch_get_main_queue(), {
self.scrollRangeToVisible(NSMakeRange(text.lengthOfBytesUsingEncoding(NSUTF8StringEncoding) - 1, 0))
})
}
})
}
}
What this does is it updates the text, then uses a stored value of the UITextView.contentOffset property (or anything you pass as a parameter), and sets the offset of the view accordingly. If desired, after this, it scrolls to the end of the new, potentially changed content.
I'm new to iOS programming and I don't know why it works so well it does, if someone has some information on this it would be nice to know. Also the approach may not be perfect so I'm open to improvement ideas as well.
And of course thanks to NixonsBack for posting the answer behind the link above.
My first post :), cheers!
Put this one line of code in ViewDidLoad
self.automaticallyAdjustsScrollViewInsets = false
The following code should give you effect you want.
[self.scrollView setContentOffset:CGPointMake(0, -self.scrollView.contentInset.top) animated:YES];
You'll need to replace "self.scrollView" with the name of your scroll view. You should put this code in after you've set the text of the scroll view.
This worked for me:
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
textView.scrollRectToVisible(CGRect(origin: CGPointZero, size: CGSizeMake(1.0, 1.0)), animated: false)
}
This worked for me with Xcode 8.3.3:
-(void)viewWillLayoutSubviews
{
[super viewWillLayoutSubviews];
[self.txtQuestion scrollRangeToVisible:NSMakeRange(0, 0)];
}
Create an outlet for your UITextView in the ViewController.swift file. In the ViewDidLoad section put the following:
Swift:
self.textView.contentOffset.y = 0
I have tried:
self.textView.scrollRangeToVisible(NSMakeRange(0, 0))
I translated zeeple's answer to MonoTouch/Xamarin (C#).
public override void ViewDidLayoutSubviews()
{
base.ViewDidLayoutSubviews();
myForm.SetContentOffset(new CoreGraphics.CGPoint(0,0), animated: false);
}
I had to implement two answers here to get my view working as I want:
From Juan David Cruz Serrano:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
textView.setContentOffset(CGPoint.zero, animated: false)
}
And from Murat Yasar:
automaticallyAdjustsScrollViewInsets = false
This gave a UITextView that loads with the scroll at the very top and where the insets are not changed once scrolling starts. Very strange that this is not the default behaviour.
To force the textView to start at the top every time, use the following code:
Swift 4.2:
override func viewDidLayoutSubviews() {
textView.setContentOffset(CGPoint(x: 0, y: 0), animated: false)
}
Objective-C:
- (void)viewDidLayoutSubviews {
[self.yourTextView setContentOffset:CGPointZero animated:NO];
}
Swift 4.2 & Swift 5
set content offset both before and after setting the text. (on the main Thread)
let animation = false //or whatever you want
self.mainTextView.setContentOffset(.zero, animated: animation)
self.mainTextView.attributedText = YOUR_ATTRIBUTED_TEXT
self.mainTextView.setContentOffset(.zero, animated: animation)
In my case I was loading a textView in a Custom tableview cell. Below is what I did to make sure the text in a textview loads at the top of the text in my textview in my custom cell.
1.) In storyboard, set the textview ScrollEnabled = false by unchecking the button.
2.) You set the isScrollEnabled to true on the textview after the view loads. I set mine in a small delay like below:
override func awakeFromNib() {
super.awakeFromNib()
let when = DispatchTime.now() + 1
DispatchQueue.main.asyncAfter(deadline: when){
self.textView.isScrollEnabled = true
}
}
Regardless, if you are in my situation or not, try setting scrollEnabled to false and then when the view loads, set scrollEnabled to true.

iOS. UITextView. Text jumping after UIKeyboardDidHideNotification

I have editable UITextView and keyboard dismiss mode is interactive. Also my controller is listening two notifications: UIKeyboardWillShowNotification, UIKeyboardWillHideNotification.
func keyboardWillShow(notification: NSNotification) {
if let userInfo = notification.userInfo {
var insets = self.textView.contentInset;
let rect = userInfo[UIKeyboardFrameEndUserInfoKey]?.CGRectValue() ?? CGRectZero
insets.bottom = (rect.size.height - (CGRectGetHeight(self.view.frame) - CGRectGetMaxY(self.textView.frame)))
self.textView.contentInset = insets
self.textView.scrollIndicatorInsets = insets
}
}
func keyboardWillHide(notification: NSNotification) {
self.textView.contentInset = UIEdgeInsetsZero
self.textView.scrollIndicatorInsets = UIEdgeInsetsZero
}
This stuff works great, if text in UITextView doesn't contain any empty lines. If it do, contentOffset jumps to another, random place.
I'm not sure if this is a bug in iOS 7+, or I am doing something wrong.
If it's not a bug, how to get this going fluently without the jumping behaviour?
Thanks for your help.
I had been battling this exact same problem, when I would dismiss the keyboard the UITextView's content offset would jump back to {0, 0}. Interestingly, I only got this behavior on the device, but not in the simulator.
I originally tried to solve it by overriding UITextView's contentOffset method and having it just ignore {0, 0} values, and that was semi effective, until the content got too long, in which case it would just jump to a random offset, and set the same value 3 times (so it would set content offset to {0, 3605}, {0, 3605}, and {0, 3605} all in rapid succession).
After a long time spent looking for a solution, it turned out to be rather simple:
textview.layoutManager.allowsNonContiguousLayout = NO;
As discussed in this blog post. Hope that helps :)
I had 100% exactly the same problem as you and I also asked a question about it but no one could get it right. (I am the one who up voted and favourited your question!!)
I eventually did a workaround after 4 days of frustration. Just put the UITextView inside a UITableView (You don't need to put it inside a UITableViewCell, just drag to the UITableView then it's ok). Make your UITextView unscrollable.
The following method will make UITextView expand and update the UITableView every time it is changed. (Don't forget to connect UITextView's delegate)
func textViewDidChange(textView: UITextView) {
// Change textView height
self.textView.sizeToFit()
UIView.setAnimationsEnabled(false)
self.tableView.beginUpdates()
self.tableView.endUpdates()
UIView.setAnimationsEnabled(true)
}
The following method will make UITableView autoscroll to the cursor when UITextView becomes active.
func textViewDidBeginEditing(textView: UITextView) {
// Delay the following line so that it works properly
let delay = 0.005 * Double(NSEC_PER_SEC)
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
dispatch_after(time, dispatch_get_main_queue()) {
var rect = self.textView.caretRectForPosition(self.textView.selectedTextRange?.end)
var changedRect = CGRectMake(rect.origin.x, rect.origin.y, rect.width, rect.height+3)
self.tableView.scrollRectToVisible(changedRect, animated: true)
}
}
You also need to change the UITableView contentInset and scrollIndicatorInsets in your keyboardWillShow and keyboardWillHide methods, depending on your screen layout.

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