I'm presenting my UIViewController with modalPresentationStyle = .formSheet. Everything works as expected except interactive dismissing this controller (I drag form sheet from the top down). Controller is dismissed but it's presentingViewController doesn't move back. It remains stucked with black edges around.
If I dismiss presented controller using dismiss(animated:completion:), presentingViewController moves back as expected so it seems it doesn't work just when user dismiss it by dragging.
If you need any other details let me know. Thank you. š
I'm using iOS 13.3 and Xcode 11.2.1.
Update:
I found a problem. š This view which I presented contained UITableView. I was using my method to set its tableFooterView:
extension UITableView {
func setFooterView(_ view: UIView) {
view.frame = bounds
view.setNeedsLayout()
view.layoutIfNeeded()
let height = view.systemLayoutSizeFitting(
CGSize(width: view.frame.width, height: UIView.layoutFittingCompressedSize.height)
).height
var frame = view.frame
frame.size.height = height
view.frame = frame
tableFooterView = view
sectionFooterHeight = 0
}
}
...and I called this method in my view controller in viewDidLayoutSubviews() since I thought that this is where I should set this footer view (Simply because we were using it like this in various projects š¤·š»āāļø):
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
tableView.setFooterView(footerView)
}
But I wasn't right. Simply calling it in viewDidLoad() resolved it.
override func viewDidLoad() {
super.viewDidLoad()
tableView.setFooterView(footerView)
}
No the question is: why?
If anyone could provide correct explanation why this happens I would be grateful and I would reward him/her with bounty. š
I have a Text View (UITextView) which displays a long text that is set on runtime like so:
#IBOutlet weak var textView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
if something {
textView.text = "(very long text here)"
}
textView.contentOffset = CGPoint.zero // doesn't work
}
Unfortunately, when the Text View is displayed, the text is not scrolled to the top but somewhere in the middle.
I'm thinking, either setting the contentOffset is the wrong way of doing it or I am doing it at the wrong time (maybe the text gets changed after setting contentOffset?).
I have tried a lot, I even contacted Apple Code Level Support. They couldn't help me, really (which surprised the hell out of me) ā can you?
I'd very much appreciate it. Thank you.
I had a very similar issue, especially when using splitview and testing on the iPhoneX, I resolved this by incorporating this bit of code in my ViewController when I needed the textView to scroll to the top:
textView.setContentOffset(.zero, animated: false)
textView.layoutIfNeeded()
If you wish to scroll to the top of the textView upon loading your ViewController:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Can add an if statement HERE to limit when you wish to scroll to top
textView.setContentOffset(.zero, animated: false)
}
You may need to write more information/code because if you try this piece of code in clean project with only one VC with UITextView, you'll see that it's actually working. If you're really using some condition (if something) this might be the issue. What is this something in your real code?
You need to use viewDidLayoutSubviews() so that it set the scrollview to the top.
override func viewDidLayoutSubviews() {
textView.setContentOffset(.zero, animated: false)
}
I'm manually changing the height of the UINavigationBar in my custom UINavigationController subclass. For some reason when I add the code to alter the height in the viewDidAppear function the bar's height is correctly changed, but when I try putting the code in the viewDidLoad nothing happens. Here's how I'm doing it:
class PetNavigationVC: UINavigationController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(_ animated: Bool) {
let bounds = self.navigationBar.bounds
self.navigationBar.frame = CGRect(x: 0, y: 0, width: bounds.width, height: 74)
}
}
Can anybody help me understand why this is the case?
As mentioned in comment, in viewDidLoad method the constraints aren't even calculated and nothing is really loaded except for your class values. Also adding code to viewDidLoad can be a bit tricky too, because user can see what's happening right on demant :D
You should adjust your frames or any UI related stuff in viewWillAppear func or in method DidLayoutSubviews...
I have a UITableViewController with a UIImageView. The content is loaded with the following simple code.
#IBOutlet weak var avatarImageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
updateUI()
}
func updateUI() {
backendless.userService.currentUser.retrieveProperties()
avatarImageView.layer.cornerRadius = avatarImageView.frame.size.width/2
avatarImageView.layer.masksToBounds = true
let imgURL = NSURL(string: (backendless.userService.currentUser.getProperty("Avatar") as? String)!)
avatarImageView.sd_setImageWithURL(imgURL)
tableView.reloadData()
}
The ImageView does not appear.
But if I delete the following code, the UIImageView will be set and displayed correctly.
avatarImageView.layer.cornerRadius = avatarImageView.frame.size.width/2
avatarImageView.layer.masksToBounds = true
What am I missing? Help is very appreciated.:
PS:
Xcode 8.0
Swift 2.3
Contrains for ImageView are set to 120*120
sd_setImageWithURL = pod 'SDWebImage'
Try this:
override func viewDidLoad() {
super.viewDidLoad()
self.view.layoutIfNeeded() // <- This will update your initial view frames
updateUI()
}
What is happening is that in Xcode 8.0, by the time you hit viewDidLoad, the frame of all subviews of a controller is still x: 0.0, y: 0.0, w: 1000.0, h: 1000.0, so in effect you're making the corner radius of your avatar image view 500.0pt. When you call layout if needed, the correct frames will be calculated, and give you the value you're expecting.
One obvious problem is that you are calling updateUI too soon. In viewDidLoad, there is no UI. The view has loaded but that is all; it is not in the interface and no layout has yet taken place. Your code depends upon avatarImageView.frame, but we do not yet know what that is. You have constraints on the image view, but they have not yet taken effect! Thus you should postpone this call until after the interface is present, e.g. viewDidAppear or at least viewDidLayoutSubviews. But of course then you probably only want to call it once (typed in browser, not tested, but it will be something like this):
var didConfigureUI = false
func viewDidLayoutSubviews() {
if !didConfigureUI {
didConfigureUI = true
updateUI()
}
}
I think your problem with your controller. You have added the image view to a UITableViewController. That means constraint set to image view will not work if you use the frame in view did load. You need to change frame of the UIIMageView before use it or you need to use UIViewController. use the below code before using the frame of image view.
avatarImageView.frame.size.width = 120.0
avatarImageView.frame.size.height = 120.0
I think this will solve the problem. But you should use UIViewController if there is no special purpose of UITableViewController.
āxy.view.layoutIfNeeded()ā
needs to be called everytime iām calling a property before the view has finished loading
for example imageView.view.layoutIfNeeded() to call for the height and widths values
When I have text that does not fill the UITextView, it is scrolled to the top working as intended. When there is more text than will fit on screen, the UITextView is scrolled to the middle of the text, rather than the top.
Here are some potentially relevant details:
In viewDidLoad to give some padding on top and bottom of UITextView:
self.mainTextView.textContainerInset = UIEdgeInsetsMake(90, 0, 70, 0);
The UITextView uses auto layout to anchor it 20px from top, bottom and each side of the screen (done in IB) to allow for different screen sizes and orientations.
I can still scroll it with my finger once its loaded.
EDIT
I found that removing the auto layout constraints and then fixing the width only seems to fix the issue, but only for that screen width.
add the following function to your view controller class...
Swift 3
override func viewDidLayoutSubviews() {
self.mainTextView.setContentOffset(.zero, animated: false)
}
Swift 2.1
override func viewDidLayoutSubviews() {
self.mainTextView.setContentOffset(CGPointZero, animated: false)
}
Objective C
- (void)viewDidLayoutSubviews {
[self.mainTextView setContentOffset:CGPointZero animated:NO];
}
UITextView is a subclass of UIScrollView, so you can use its methods. If all you want to do is ensure that it's scrolled to the top, then wherever the text is added try:
[self.mainTextView setContentOffset:CGPointZero animated:NO];
EDIT: AutoLayout with any kind of scrollview gets wonky fast. That setting a fixed width solves it isn't surprising. If it doesn't work in -viewDidLayoutSubviews then that is odd. Setting a layout constraint manually may work. First create the constraints in IB:
#property (weak, nonatomic) IBOutlet NSLayoutConstraint *textViewWidthConstraint;
#property (weak, nonatomic) IBOutlet NSLayoutConstraint *textViewHeightConstraint;
then in the ViewController
-(void)updateViewConstraints {
self.textViewWidthConstraint.constant = self.view.frame.size.width - 40.0f;
self.textViewHeightConstraint.constant = self.view.frame.size.height - 40.0f;
[super updateViewConstraints];
}
May still be necessary to setContentOffset in -viewDidLayoutSubviews.
(Another method would be to create a layout constraint for "'equal' widths" and "'equal' heights" between the textView and its superView, with a constant of "-40". It's only 'equal' if the constant is zero, otherwise it adjusts by the constant. But because you can only add this constraint to a view that constraints both views, you can't do this in IB.)
You may ask yourself, if I have to do this, what's the point of AutoLayout? I've studied AutoLayout in depth, and that is an excellent question.
Swift
self.textView.scrollRangeToVisible(NSMakeRange(0, 0))
Objective-C
[self.textView scrollRangeToVisible:(NSMakeRange(0, 0))];
i had same issue! Reset to suggested constrains and just put (y offset)
#IBOutlet weak var textContent: UITextView!
override func viewDidLoad() {
textContent.scrollsToTop = true
var contentHeight = textContent.contentSize.height
var offSet = textContent.contentOffset.x
var contentOffset = contentHeight - offSet
textContent.contentOffset = CGPointMake(0, -contentOffset)
}
For iOS9 and later the textview even on viewWillAppear: is coming with CGRect(0,0,1000,1000). In order for this to work you have to call in viewWillAppear:
[self.view setNeedsLayout];
[self.view layoutIfNeeded];
// * Your code here
After that the textview will have correct CGRect data and you can perform any scrolling operation you may need.
The problem with putting code in viewDidLayoutSubviews and viewWillLayoutSubviews is that these methods are called a lot (during device rotation, resizing views etc ...). If you're reading something from text view, and you rotate the device, you expect that the part of the content you're viewing stays on screen. You do not expect that it scrolls back to top.
Instead of scrolling the content to top, try to keep text view's scrollEnabled property set to NO (false), and turn it back on in viewDidAppear.
If you don't wanna mess with constraints:
override func updateViewConstraints() {
super.updateViewConstraints()
}
override func viewDidLayoutSubviews() {
self.textLabel.setContentOffset(CGPointZero, animated: false)
}
This is an interesting bug. In our project, this is only occurring on devices with an iPhone 5-size screen. It appears that the textview contentOffset changes at some point during the view controller lifecycle. In viewDidLoad and viewWillAppear the textview's contentOffset is 0,0, and by viewDidAppear it's changed. You can see it happening in viewWillLayoutSubviews. Constraints appear to be set up correctly.
This will ensure you don't call a scrolling method unless it's needed:
if textView.contentOffset.y > 0 {
textView.contentOffset = CGPoint(x: 0, y: 0)
// Or use scrollRectToVisible, scrollRangeToVisible, etc.
}
Swift
override func viewDidLoad() {
super.viewDidLoad()
textView.isScrollEnabled = false
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
textView.isScrollEnabled = true
}
For me this works in a different way, I tried all things mentioned above but none of the worked in func viewWillAppear(_ animated: Bool). Which eventually makes textView scrolled up, and in func viewDidAppear(_ animated: Bool) it would scroll after screen appeared.
Below worked for me but got some constraint related issue with keyboard up and down.
override func viewDidLayoutSubviews() {
self.textView.setContentOffset(.zero, animated: false)
}
Below worked as expectation:
override func viewDidLoad() {
super.viewDidLoad()
self.textView.scrollsToTop = true
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.view.layoutIfNeeded()
self.textView.setContentOffset(.zero, animated: false)
}
David Rectors answer in Objective C:
#import "TopTextView.h"
#implementation TopTextView
bool scrolled = NO;
- (void) layoutSubviews
{
[super layoutSubviews];
if (!scrolled) {
[self setContentOffset:CGPointMake(0, 0) animated:NO];
scrolled = YES;
}
}
#end
It seems like a terrible idea to handle this issue in code in the view controller because: A. The view controller isn't making any mistake or doing anything wrong, and B, if you have more than one view controller with a wrongly scrolled text view, you end up with redundant code. The solution should be to write code that exists in the text view class. My solution works with Interface Builder where I simply select a custom class for the UITextView and use this class:
import Foundation
import UIKit
class TopTextView: UITextView {
var scrolled = false
override func layoutSubviews() {
super.layoutSubviews()
if scrolled { return }
setContentOffset(.zero, animated: false)
scrolled = true
}
}
This worked for me. I happen to have a view controller with a child view with a UITextView as a child of that view, not with a UITextView as the child of the view controller. I don't know how well this works if the text view is under top or bottom bars but since no edge insets are touched, this should work.
In my case I had to do it like this:
textView.setContentOffset(CGPoint(x: 0, y: -self.textView.adjustedContentInset.top), animated: false)
because the texview was underneath the navigation bar and had an adjusted inset