Unable to get the correct frame for UIViewControllerAnimatedTransitioning to UIPageViewController - swift

I have been battling this transition animation and I am pretty much out of ideas. I am attempting something similar to going from the collection to the individual photos in the Photos app on iOS.
It all works to my satisfaction with the exception that the frame for the "big" detail view of the image is not correct. It is the right size but it is about 87 points closer to the top of the screen compared to the actual position of the image in the final state. This is pretty much the same height as what is above the "safe area" (iPhone X titles + navItem) and irritatingly close to what is also below the safe area (toolbar and iPhone X home area).
I have Googled (and "SO'd") a bunch of different solutions to similar sounding problems. E.g: UIViewControllerAnimatedTransitioning with Safe Area Insets on iPhone X
I have downloaded and perused example code from Github. E.g: https://github.com/SamStone92/CustomTransitions
It seems to me that I have something in my view (controller) hierarchy which is complicating this more than most. I would love some hints as to what might be causing the problem and how I might go about fixing it.
My hierarchy is:
NavigationController containing the root VC with a UICollectionView.
Tapping a cell transitions to a UIPageViewController for a "detail view" where I can page between items in the collection.
UIPageViewController has a bottom toolbar in addition to the navigation bar.
The content ViewController has a ScrollView with a UIImageView in it to get some zooming.
Seems like the common approach is to add the destination view to the container, force a layout pass and then get the frame. I have tried many variants of this with and without converting the coordinates. (they appear to always remain the same before and after conversion)
My Theory
I am leaning towards the UIPageViewController being the complicating factor. But I have not been able to untangle how to get the correct coordinates.
The destination view (in the animation) is not the content view but the PageVC view which in turn may or may not have added the content view, adapted it to the navigation item or the toolbar.
Seems like viewWillAppear on the content VC does not have the right coordinates. I can tell that the detail content view is getting a call to viewWillLayoutSubviews after that and also after all the animation delegation stuff has had its turn.
This is a color overlay of my main views. Grey is the top and bottom areas outside the safe area. Blue is where the transition animates to before revealing the green, underlying actual position it should have animated to.

Related

How to get the visible view size in iOS13 when presenting a view controller

In iOS13, the default way when presenting a view controller was changed to the "sheets/cards" view. As I’m not using auto layout (why not, is not really important and relevant), I rely on getting position of elements based on the frame of the view.
Now, the problem with the new method is, that the view frame doesn’t really reflect the actual content size visible on the screen anymore. E.g. if I have positioned a UIButton at the bottom on the view controller based on the view.frame bottom coordinate, it will be now cut off, as the view is actually moved down in the amount of the nice "sheets/cards" visual indication at the top. The same problem is even more evident in an iPad, where centring another view in the view controllers view will be offset, due to the fact that the default presentation style is now a "sheet" in the middle of the screen.
I’ve currently changed everything to force the full screen version, but it would be nice to use the new fancy design.
Anybody has any idea how to get the actual visible rect/coordinates in the new style without changing things to auto layout?
Here are how they look. The "flower" is centered in the view and the X button should not be so close to the bottom or missing completely in the iPad version.
Finally figured it out. As I was setting the positions of items in viewDidLoad, the frame was not calculated correctly, thus resulting things being laid out incorrectly. When resetting the frame and positions in viewDidLoadSubviews, the positions were placed correctly.

UIScrollView Controller not scrolling fully

I am pretty sure this has something to do with the dreaded AutoLayout. (been trying since 2days to get hang of it)
So I mastered it somewhat, but now I have problem where my UIScrollView is not scrolling fully down, pictures are much better at explaining these things
this is the scroll view
this is the content view
so the problem is the scrolling is happening but then again it springs back up. So I am not able to click on the signup button
EDIt 1
Edit:
I have created a little example on github for you to look at, here. The project illustrates the answer below and uses the techniques I describe and nothing else.
Original Answer:
couple of things I would advise here.
First, I know you've been trying for a while but remove all the current constraints (painful I know but). Do this for clarity as ....
The view should be the size of the scene, it looks like you want the scrollview to be the full screen so that too needs to be the size of the scene.
e.g. if you are designing at 6Plus by default the scene size is 414x736 so the view and the scrollview it contains should also be 414x736.
Only the content view needs to be the size of the real content you wish to show. Let's say for arguments sake that the content is 414x1000.
Now the constraints for the scrollview are simple. It needs zero spacing to all it's edges.
You can add the content view to the scrollview in a couple of ways. The way I try to do this varies from project to project and depends mostly on how complex the scene is. If it's a really busy scene I keep the content view outside of the scrollview in interface builder so that I can work on it easily and visualize the whole of the view. Then I add the content view to the scrollview in code.
If its a simpler view You can add it inside the scrollview in interface builder. Ultimately whichever way you do it, you can lose visibility of the content view in interface builder because the contentview is larger than the scrollview and the content gets obscured. So play about and find a good way for you.
Define the content view and all it's subviews. The content view needs to be taller than the scrollview otherwise it wont scroll. All of the content view's subviews need to have defined heights from top to bottom and widths from left to right. In your case the scrollview is scrolling vertically not horizontally so all the widths need to add up to the width of the scroll view BUT the heights need to add up to the full height of the content view.
Note: if you do this proportially your life will be easier later. If you do all this with fixed heights the storyboard will break on different device sizes.
Now the "tricky bit" and it's a bit counter intuitive. You need to pin the content view to the scrollview, remember the height of the content view is taller than the scrollview. In all other circumstances in Interface Builder pinning a view to a superview (0 padding) will adjust the height (or width) accordingly. For the relationship between a scrollview and it's content view this doesn't happen.
First pin the contentview
Notice the -400? Remember the content view is taller than the scrollview and we will change this immediately.
Select the bottom constraint (-400) that we have just created:
Select the drop down arrow next to the constant value:
Select Standard Value and type in 0 for the constant.
You should now have a storyboard with no broken constraints and if you build and run you should get a scrollview as desired.
Your bottomspace to superview on your content view is set to -74.0, I don't know if there is a reason you had to do that, but try setting it to -8.0. I think your scroll view is scrolling up to the 0.0 mark automatically

Which ViewController Concept to use?

i need the following view layout in my application.
the green view is the viewport of the ios application.
on the top (the blue ones) are views that should be swipeable left and right but only one view (different content) is visible at a time. this views should snap in place if i swipe.
under this, there are more views arranged horizontally (the orange ones). this should also snap in place (always centered so that one view is in the grey section) after swiping. here is more than one view visible at a time.
there are concepts like PageViewController, UIScrollView, UICollectionView and so one.
which one to choose for something like this?
Also is it a good idea to add subViewControllers with this layout? A Controller for each of the scroll views?
thanks in advance.
For the Top I would go with a 3 UIViewController's UIView (depending on the complexity of the objects). If they are simple things I would just add 3 UIView's and and handle the logic in the same UIViewController. Either putting the 3 inside a UIScrollView (with pagingEnabled) or you handling the gestures are both valid possibilities. The botton UIViews (orange) could be with a UICollectionView (so it could handle the memory for you). A UIScrollView for the botton, could work, but if you have too many you can have performance issues.

iPhone: How to create title bar like in Google+ stream?

I'm about to create an app with the same technology like the Google+ app. I want to reproduce the "stream"-viewcontroller.
Currently i've set up a scrollview with paging and pagecontrol, but I can't get how the bar under the navigationbar in the Google+-app is created. It shows the titles of the current page and the pages to the left and right. It also has a zoom-effect that zoom in at the current visible pagetitle.
Anyone has any ideas?
One way to do it would be to create your VC, throw a scrollview in it whose x, y and width are the same as your backing view, but whose height is the height of your backing view minus however high you want your titlebar to be. Create a separate view for that. Your paging scrollview will work fine for the content area.
For your titlebar, you'll probably just set up some CABasicAnimations and keep some images off screen, sliding them around as you see fit, or what-have-you. This is one approach you can use.

Why is there a 20-pixel-high dark overlay over my app's navigation bar?

Once again, I'm almost entirely sure this is something dumb that I'm doing, but I've been banging my head against this one for hours & am getting nowhere.
I'm trying to restructure the view hierarchy of my app. I need to be able to detect user interface orientation changes globally in order to correctly rotate a "Loading" view displayed when the app is downloading content. (device orientation changes seem to fire at different times, causing the view that needs to respond to these events to rotate sporadically).
The app previously added a UINavigationController's view to the main window. I modified the hierarchy to add the view of a UIViewController subclass to the main window, and added the view of the UINavigationController to the subclass's view. The UIViewController subclass manages the display & rotation of the "Loading" subview, and I was expecting the rest of the app to continue behaving normally, as inserting one extra empty view into the hierarchy didn't feel like I was changing too much.
My initial problem was the positioning of the UINavigationController - it was 20 pixels too low, resulting in a gap between the status bar and the navigation bar, and cutting off the bottom 20 pixels of the tab bar. I was able to adjust this by setting the frame property of the UINavigationController's view to the bounds property of the UIViewController's view, which corrected the position.
However, now I'm stuck with a 20-pixel-high dark "overlay" on top of my navigation bar. If I were to guess, I'd say it was black with 50% opacity. Touch events on this bar don't work (e.g. if I try to tap the "Back" button through the overlay, nothing happens). The fact that the height is equal to that of the status bar hasn't escaped me, but I'm at a total loss as to what could be causing it.
I hate feeling this stupid, so if anyone has any insight into this problem, you'd really make my day. Thanks in advance!
OK, a few things pop out from your post.
My initial problem was the positioning of the
UINavigationController - it was 20
pixels too low
This makes me believe it is related to your new problem.
I was able to adjust this by setting
the frame property of the
UINavigationController's view to the
bounds property of the
UIViewController's view
This sounds like the view it was loaded onto was offset 20 pixels, and when you set it to the bounds, it repositioned it on the windows view space.
Touch events on this bar don't work
(e.g. if I try to tap the "Back"
button through the overlay, nothing
happens)
This is the big thing. If touch events aren't being sent to the view, then what that means is that the OS doesn't see a view where you are pressing (or rather the view you want it to), so that view doesn't get the message to do something.
From what you have said, I believe your problem is with your base view controller that you just added. Try redoing the frame on, making it conform to where you want. Then take out the code you put in to set the navigation controllers frame. The navigation controller should fit to the view you added too, and once you have that main view where it needs to be (20 pixels higher apparently), then everything should work.