This a little bit wierd i have made UIPageController that works and everything is fine. But when i put it inside UINavigationController, it offset from the for status bar. Than i swipe up on that screen it positions itself right and everything is ok. I don't really understand what is happening. Here are the images
try setting adjustScrollViewInsets to false on UIPageController.
This is the property that determines whether the system should automatically add inset to a UIScrollView in your view controller's view hierarchy when it is being displayed behind transparent bars (here , the navigation bar). What happened here is that the system assumed the bounds of the page controller overlaps with that of the nav bar and so it adds insets so that the view's contents is fully visible and is not obscured by the nav bar. But in this case it is wrong since it seems your page controller's bounds starts at the bottom edge of the nav bar.
I think you can also set the nav bar as opaque to disable the automatic adding of insets.
Related
I'm using a UITableViewController embedded in a navigation controller, I've checked the "hide bars on swipe" for the navigation controller in the storyboard. No crazy code, scrollview functions are not overridden, didn't write any code that would offset any views.
When I scroll up the tableview a tiny bit and release it when the navigation bar is half hidden, the whole table gets offset and it's off screen (sometimes the top left corner of the table is visible), then if I scroll up the table view a bit, it's back to its normal position, if I check "adjust scroll view insets" in the storyboard, the whole screen flashes black.
Has anyone encountered the same problem?
p.s. I'm using Xcode 9 beta with iOS 10.3, not sure if this has anything to do with it.
EDIT:
Scroll navigation bar half way
The view after releasing
So I created a new set of TableviewController and NavigationController, and tested it step by step by adding changes to it, it turned out that I had set my navigation bar to be translucent in the storyboard, once I unchecked it the issue was resolved. There's still an unwanted bounce effect if I release the navigation bar at half hidden position, which appears to be the view adjusting the offset, but it's way better than what it was like.
P.S. make sure "Adjust scroll view insets" is checked.
EDIT:
Turns out setting extendedLayoutIncludesOpaqueBars to True also resolves this issue, if you want to keep the navigation bar opaque.
EDIT: Small update to my issue, what i did as a solution for now was obviously just having my scrollview white. This fixes my issue, but my real curiosity was to why exactly the content view was doing what i explained below. Also still curious to what common practice formatting is when adding a scroll view to a VC with a navigation bar.
So i am a bit confused with what is going on here. I have a VC with a navigation bar at the top and i need to add a Scroll view to it. So when i did that i stretched it to just below the navigation bar at the top of the screen, then added constraints. (I also made the ScrollView background red so i could differentiate it from the content view)
Secondly i added a UIView which i named Content view and i stretched it to the exact same position as the Scroll view. Then added constraints for that as well. (No objects were added yet)
I then ran the app to check how it looked and i noticed that under the navigation bar my there was a big chunk of red, meaning the Scroll view was full screen in the correct position right below the nav bar, but my content view was not.
A couple things i did to fix this was
I extended the Scroll view all the way to the top of the VC, past the nav bar, but when i ran the app i could see red behind the nav bar, which i figured meant it was not right.
I extended just the content view to the top of the VC, but this did not seem right to me either, even though both seemed to fix the problem.
So my questions are:
When adding views in general to a VC with a nav bar at the top should i be extending those views only to the bottom of the nav bar, or all the way to the top of the VC?
I am new to Scroll views as this is my first time dealing with one, am i missing something in this situation? Or doing something wrong?
Your help is greatly appreciated, thank you.
1) Move the scroll view all the way up and beyond nav bar.
2) Have the scroll view match the height of its parent.
I'm experiencing a strange issue with MKMapView placed in a view with a navigation bar. Given a UIScrollView in the same situation, whose width, height, and center are constrained to it's superview (the view controller's view object) the insets will be adjusted if the controller's automaticallyAdjustsScrollViewInsets property is set to YES, and not if set to NO. That's great. I can not find this documented anywhere, but the map view seems to do the same thing, but it's not possible to disable it. Setting automaticallyAdjustsScrollViewInsets has no effect.
In brief(ish):
In the image below, the small back square is centered within the view, regardless of navigation bar. The map view is also constrained to be exactly the size of the view (it extends behind the nav bar). The location of the map view was set to be the current location (also indicated by the blue circle) so I would expect them to match, but they are off by half the combined height of status and navigation bars.
Is there an explanation for this behavior, and a way to get it to work as expected?
This is very strange because an MKMapView is not a subclass of a UIScrollView but it is behaving like one in this case. That's not completely unreasonable, but I would expect the auto adjusting insets to work consistently on a map view and a scroll view.
Workaround
Something awful like this would 'solve the problem':
MKCoordinateRegion region = MKCoordinateRegionMake(self.coordinate, MKCoordinateSpanMake(0.008, 0.008));
MKMapRect mapRect = MKMapRectForCoordinateRegion(region);
[self.mapView setVisibleMapRect:mapRect edgePadding:UIEdgeInsetsMake(0, 0, 64, 0) animated:YES];
Either adjusting the bottom inset as well, or adding a negative inset on the top gets things lined up, but it would break if this behavior of the map view changes, or if the view controller is presented without a navigation bar, or if there is a stiff breeze. It also erodes my confidence in pulling correct coordinates back out of the map view.
MKMapView does indeed sit under the navigation bar, but automatically uses a housing view controller's topLayoutGuide to shift annotations and the compass view, etc. down from under it.
You should make sure that your own views take this into account in their autolayout code.
If you take a look at this, you can see that the mapview is very likely not sitting under the navigation bar, as you think. It is sitting between the bottom of the nav bar and the bottom of the superview.
On another note, the navigation bar is translucent by default, so if the mapview was really sitting under the nav bar you would be able to see through it, assuming you didn't disable the default nav bar behavior.
I have a rather simple screen where I am inserting a custom UINavigationBar at the top of the screen and a content area below it. I'm using AutoLayout and I'm visually declaring the relationship as so:
#"V:|-0-[_navBar(65)]-0-[_content]-0-|";
Now, this seems to work perfectly until I tried to have another view slide down from under the navigation bar. The nav bar contains a search field and I want the search results to slide down from under nav bar. As the code currently stands, the search results slide down on top of or in front of the nav bar and it looks quite strange. So I tried to push the nav bar to the top of the index stack using:
[self.view bringSubviewToFront:_navBar];
As far as the animation is concerned, it works perfectly. The search results no longer slide over the nav bar but they are in front of the content area. When the child of _content is a UIView it seems to be OK. However, when the child of _content is a UIScrollView, this seems to have introduced a 20px margin between the nav bar and the content area. Honestly, the space seems to be very close in size to the status bar although the nav bar has stayed the same height. I've tried bringing the nav bar to the front using many different techiniques but as soon as the nav bar and the content area are on different planes, it seems to break the autolayout constraint of 0px that is defined above.
Here is a sample project to show the bug. Look at the third item, "bringSubViewToFront bug".
Does anyone know what's going on?
The 20 point space seems like it would have something to do with the status bar, but I'm not sure why bringing the navigation bar to the front would apparently cause the scroll view to inset its content. Anyway, I was able to fix it by adding this line, after you bring the navigation bar to the front,
_scrollView.contentInset = UIEdgeInsetsMake(-20, 0, 0, 0);
I have a UINavigationController with standard UINavigationBar. When presenting certain UIViewControllers and orientations, the UINavigationBar may or may not appear and it may or may not have a prompt element. This means that the bar height changes frequently.
I have some subviews below the UINavigationBar set with NSLayoutConstraints to topLayoutGuide. It generally lays out as expected, adjusting vertical position of the subviews appropriately based on the height of the UINavigationBar. What it does not do is move the subviews at times when the UINavigationBar is animated after the view is already displayed.
Specifically, coming from a state with UINavigationBar hidden, transition to a UIViewController which does not hide the navigation bar to one which does. The view displays, then navigation bar animates into place. The subviews do not move down. If I rotate the device, every things lays out appropriately again. Only when animating the navigation bar in and out or to display/hide the prompt I not find a hook to reevaluate the constraints.
I tried [self.view updateConstraints] and [self.view updateConstraintsIfNeeded] in various places such as viewDidAppear, viewDidLayoutSubviews. Nothing seems to update that topLayoutConstraint.
I am familiar with edge restraints, translucent navigation bar and other various methods of keeping the entire view from appearing under the navigation bar. I do want to keep view full size and I want the translucent bar so these are not solutions for me. It seems the constraints should handle this automatically, hence the "auto" in auto layout.
To simplify, for recreation, UINavigationController with rootViewcontroller showing normal navigation bar with just a title. In viewDidLoad of the next presented viewController I have [self.navigationContoller setPrompt:self.myPrompt]. The view is presented, when the prompt is set, the navigation bar grows larger. Some labels below the bar are set with relation to topLayoutGuide, which places them correctly initially. I expect they would move down when the bar grows. Rotate device back and forth, they now layout correctly. Pop the viewController and push back to top, repeats as above.
So, it turns out it was all me. After trying all manner of forcing layout updates in all sorts of ways, the solution was to move the [myView setPrompt:myPrompt] out of viewDidLoad and call it in viewDidAppear instead.
Works completely as expected. Navbar grows, subviews shift and shrink as needed. Now I have to hunt down all the experimental code I plastered everywhere trying to do it wrong.