I'm trying to implement a function where there will be a somewhat permanent banner on top of my UITabBar from my TabBarController. To avoid ruining the content in the viewController.view I would like to use some kind of content-inset.
If all the viewControllers of the tabBarController were tableViews or scrollViews, then I could change their contentInset, but not all of them are.
I have tried changing the viewController.view.frame to have a shorter height (to make room for a 44px banner below view and above tabBar), but the view won't update. I'm guessing it doesn't like the idea of the 44px 'void' in the viewController itself (as nothing is below the UIView).
I have thought of a few different ways:
Somehow changing the height/origin of the actual TabBar without changing the design, making 44px extra room at the top of the tabBar, which would hopefully update the 'above' viewController's constraints
Somehow edit the viewController.view's constraints to give space between the TabBar and the bottom of the view.
Somehow change the BottomLayoutGuide programmatically
Are any of these possible? I have searched, without any luck.. Are there any other ways of doing this to a general UIViewController?
To clarify, I do have own classes for each of the ViewControllers in the TabBarController, but I would like to find a way of achieving this without having to change any code of the viewControllers. -> I want to make this change solely from the UITabBarController. (eg. (pseudo) self.viewControllers.view.frame.size.height -= 44; (not actually code, shortened)(which doesn't work))
I would advise you to use bounds property of UIView to do the trick. This is how I would do this:
Step 1 : Add a category on UIViewController to change the view controller's view down by passed in points:
UIViewController.MyAddition.h
#import <Foundation/Foundation.h>
#interface UIViewController (MyAddition)
- (void)moveViewDownBy:(CGFloat)iDownPoints;
#end
UIViewController.MyAddition.m
#import "UIViewController+MyAddition.h"
#implementation UIViewController (MyAddition)
- (void)moveViewDownBy:(CGFloat)iDownPoints {
CGRect bounds = self.view.bounds;
bounds.origin.y -= iDownPoints;
bounds.size.height = -iDownPoints;
self.view.bounds = bounds;
}
#end
Step 2 : Call this category on your ViewController's loadView method:
[self moveViewDownBy:<Height_Of_Your_Top_Banner>];
You can't change height of a viewController's frame.Because it's height/width is readonly
So,do with this tricky
CGRect frame = self.viewControllers.view.frame;
frame.size.height -=44;
self.viewControllers.view.frame = frame;
I got a view controller hierarchy with the following parent-child relationship:
UINavigationController (contains) MainViewController (contains) UIPageViewController (contains) UITableViewController
In the inner-most UITableViewController, I have automaticallyAdjustScrollViewInset set to YES, however this setting doesn't seem to work. As can be seen in the screenshot below, the table view's contentInset doesn't seem to be adjusted with the navigation bar.
My goal is to have this table view's contentInset to be automatically adjusted with the outer-most navigation bar. If the navigation bar or the status bar is hidden, I want the content inset to adjust accordingly.
How can I do that? Thanks!
The UINavigationController adjust its child view controller's topLayoutGuide automatically.
In your case it is not being propagated down far enough.
If you make sure this topLayoutGuide makes it down to your table view controller then you won't have to set the contentInset manually.
Also, your view controller hierarchy seems overly complex (I don't know the details of your project). This simplified version of what you have will give you what you are after for free.
Apparently the outer-most UINavigationController is still accessible to the inner-most UITableViewController via its navigationController property.
Because the navigation bar's frame is accessible by the inner-most view controller, we can do something like this in its viewDidLayoutSubviews.
- (void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
self.tableView.contentInset = UIEdgeInsetsMake(CGRectGetMaxY(self.navigationController.navigationBar.frame), 0, 0, 0);
self.tableView.scrollIndicatorInsets = self.tableView.contentInset;
}
I have a UIPageViewController with translucent status bar and navigation bar. Its topLayoutGuide is 64 pixels, as expected.
However, the child view controllers of the UIPageViewController report a topLayoutGuide of 0 pixels, even if they're shown under the status bar and navigation bar.
Is this the expected behavior? If so, what's the best way to position a view of a child view controller under the real topLayoutGuide?
(short of using parentViewController.topLayoutGuide, which I'd consider a hack)
While this answer might be correct, I still found myself having to travel the containment tree up to find the right parent view controller and get what you describe as the "real topLayoutGuide". This way I can manually implement automaticallyAdjustsScrollViewInsets.
This is how I'm doing it:
In my table view controller (a subclass of UIViewController actually), I have this:
- (void)viewWillLayoutSubviews {
[super viewWillLayoutSubviews];
_tableView.frame = self.view.bounds;
const UIEdgeInsets insets = (self.automaticallyAdjustsScrollViewInsets) ? UIEdgeInsetsMake(self.ms_navigationBarTopLayoutGuide.length,
0.0,
self.ms_navigationBarBottomLayoutGuide.length,
0.0) : UIEdgeInsetsZero;
_tableView.contentInset = _tableView.scrollIndicatorInsets = insets;
}
Notice the category methods in UIViewController, this is how I implemented them:
#implementation UIViewController (MSLayoutSupport)
- (id<UILayoutSupport>)ms_navigationBarTopLayoutGuide {
if (self.parentViewController &&
![self.parentViewController isKindOfClass:UINavigationController.class]) {
return self.parentViewController.ms_navigationBarTopLayoutGuide;
} else {
return self.topLayoutGuide;
}
}
- (id<UILayoutSupport>)ms_navigationBarBottomLayoutGuide {
if (self.parentViewController &&
![self.parentViewController isKindOfClass:UINavigationController.class]) {
return self.parentViewController.ms_navigationBarBottomLayoutGuide;
} else {
return self.bottomLayoutGuide;
}
}
#end
Hope this helps :)
I might be wrong, but in my opinion the behaviour is correct. The topLayout value can be used by the container view controller to layout its view's subviews.
The reference says:
To use a top layout guide without using constraints, obtain the guide’s position relative to the top bound of the containing view.
In the parent, relative to the containing view, the value will be 64.
In the child, relative to the containing view (the parent), the value will be 0.
In the container View Controller you could use the property this way:
- (void) viewWillLayoutSubviews {
CGRect viewBounds = self.view.bounds;
CGFloat topBarOffset = self.topLayoutGuide.length;
for (UIView *view in [self.view subviews]){
view.frame = CGRectMake(viewBounds.origin.x, viewBounds.origin.y+topBarOffset, viewBounds.size.width, viewBounds.size.height-topBarOffset);
}
}
The Child view controller does not need to know that there are a Navigation and a Status bar : its parent will have already laid out its subviews taking that into account.
If I create a new page based project, embed it in a navigation controller, and add this code to the parent view controllers it seems to be working fine:
you can add a constraint in the storyboard and change it in viewWillLayoutSubviews
something like this:
- (void)viewWillLayoutSubviews
{
[super viewWillLayoutSubviews];
self.topGuideConstraint.constant = [self.parentViewController.topLayoutGuide length];
}
The documentation says to use topLayoutGuide in viewDidLayoutSubviews if you are using a UIViewController subclass, or layoutSubviews if you are using a UIView subclass.
If you use it in those methods you should get an appropriate non-zero value.
Documentation link:
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html#//apple_ref/occ/instp/UIViewController/topLayoutGuide
In case if you have UIPageViewController like OP does and you have for example collection view controllers as children. Turns out the fix for content inset is simple and it works on iOS 8:
- (void)viewWillLayoutSubviews {
[super viewWillLayoutSubviews];
UIEdgeInsets insets = self.collectionView.contentInset;
insets.top = self.parentViewController.topLayoutGuide.length;
self.collectionView.contentInset = insets;
self.collectionView.scrollIndicatorInsets = insets;
}
This has been addressed in iOS 8.
How to set topLayoutGuide position for child view controller
Essentially, the container view controller should constrain the child view controller's (top|bottom|left|right)LayoutGuide as it would any other view. (In iOS 7, it was already fully constrained at a required priority, so this didn't work.)
I think the guides are definitely meant to be set for nested child controllers. For example, suppose you have:
A 100x50 screen, with a 20 pixel status bar at the top.
A top-level view controller, covering the whole window. Its topLayoutGuide is 20.
A nested view controller inside the top view covering the bottom 95 pixels, eg. 5 pixels down from the top of the screen. This view should have a topLayoutGuide of 15, since its top 15 pixels are covered by the status bar.
That would make sense: it means that the nested view controller can set constraints to prevent unwanted overlap, just like a top-level one. It doesn't have to care that it's nested, or where on the screen its parent is displaying it, and the parent view controller doesn't need to know how the child wants to interact with the status bar.
That also seems to be what the documentation--or some of the documentation, at least--says:
The top layout guide indicates the distance, in points, between the top of a view controller’s view and the bottom of the bottommost bar that overlays the view
(https://developer.apple.com/library/ios/documentation/UIKit/Reference/UILayoutSupport_Protocol/Reference/Reference.html)
That doesn't say anything about only working for top-level view controllers.
But, I don't know if this is what actually happens. I've definitely seen child view controllers with nonzero topLayoutGuides, but I'm still figuring out the quirks. (In my case the top guide should be zero, since the view isn't at the top of the screen, which is what I'm banging my head against at the moment...)
This is the approach for the known guide length. Create constrains not to guides, but to view's top with fixed constants assuming guide distance will be.
Swifty implementation of #NachoSoto answer:
extension UIViewController {
func navigationBarTopLayoutGuide() -> UILayoutSupport {
if let parentViewController = self.parentViewController {
if !parentViewController.isKindOfClass(UINavigationController) {
return parentViewController.navigationBarTopLayoutGuide()
}
}
return self.topLayoutGuide
}
func navigationBarBottomLayoutGuide() -> UILayoutSupport {
if let parentViewController = self.parentViewController {
if !parentViewController.isKindOfClass(UINavigationController) {
return parentViewController.navigationBarBottomLayoutGuide()
}
}
return self.bottomLayoutGuide
}
}
Not sure if anyone still got problem with this, as I still did a few minutes ago.
My problem is like this (source gif from https://knuspermagier.de/2014-fixing-uipageviewcontrollers-top-layout-guide-problems.html).
For short, my pageViewController has 3 child viewcontrollers. First viewcontroller is fine, but when I slide to the next one, the whole view is incorrectly offset to the top (~20 pixel, I guess), but will return to normal after my finger is off the screen.
I stayed up all night looking for solution for this but still no luck finding one.
Then suddenly I came up with this crazy idea:
[pageViewController setViewControllers:#[listViewControllers[1]] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:^(BOOL finished) {
}];
[pageViewController setViewControllers:#[listViewControllers[0]] direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:^(BOOL finished) {
}];
My listViewControllers has 3 child viewcontrollers. The one at index 0 has problem, so I firstly set it as root of pageviewcontroller, and right after that set it back to the first view controller (as I expected).
Voila, it worked!
Hope it helps!
This is an unfortunate behavior that appears to have been rectified in iOS 11 with the safe-area API revamp. That said, you will always get the correct value off the root view controller. For example, if you want the upper safe area height pre-iOS 11:
Swift 4
let root = UIApplication.shared.keyWindow!.rootViewController!
let topLayoutGuideLength = root.topLayoutGuide.length
I've been struggling with this for quite a while now.
I have to implement an user profile similar to what Instagram has in their ios app.
When clicking on the first to buttons on that tab bar like thing all the contents downwards from it changes. The tableview that is displayed on the bottom part has dynamic size so they keep account of that also.
I have something implemented where the top part is a UIView with 5 buttons and based on them the bottom part (witch is like a container view) changes content. And these two (top uiview and bottom container view) are part of UIScrollView. But this way I can't get information back in time on the size about the tableview's size that I want to display in the bottom part in order to modify the UIScrollView's size. And I have a feeling this is a flawed way to do it.
I would really appreciate any ideas oh how to implement this king of interaction. Thank you.
I believe it's a headerView on a UITableView or a UICollectionView, depending on which view mode you have selected. When you tap one of the buttons it changes out the UITableView to a UICollectionView or vice versa.
You want to keep track of the current contentOffset for whichever is being displayed (UICollectionView and UITableView are both subclasses of UIScrollView so you will be able to get this from both) and then set the contentOffset on the view you're switching to.
Setup an ivar for the UIView header subclass so you can easily re-use it.
This is what I have. My problem is that I'm mot getting back in useful time the tableview's frame height from the tableview controller to the UserProfileViewController in order to change the latter's scrollview size. I also feel that I'm somehow doing this backwards so any suggestions are more than welcome.
This view has two parts: an upper part and a lower part. The parent view is a scroll view. What I wanted to achieve with this is having a sort of tab bar in the upper part that will controll waht will appear in the lower part.
The upper part has a flip animation when the upper left button is pressed to reveal another view.
The way this is achieved is by having 2 views: a dummy view and the back view. The dummy view has the front view as a child. The front view is the one that containes all the buttons.
The code for this animation is achieved in this way:
- (IBAction)infoButtonPressed:(id)sender
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1.0];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.hoverView cache:YES];
if ([self.headerView superview]) {
[self.headerView removeFromSuperview];
[self.hoverView addSubview:self.backOfHeaderView];
[self.infoButton removeFromSuperview];
[self.backOfHeaderView addSubview:self.infoButton];
} else {
[self.backOfHeaderView removeFromSuperview];
[self.hoverView addSubview:self.headerView];
[self.infoButton removeFromSuperview];
[self.headerView addSubview:self.infoButton];
}
[UIView commitAnimations];
}
The lower part is made out of a container view that acts as a place holder.
When a button is pressed a different view controller is displayed in the container view.
Each view controller has a container view of it's own. The specific view of that view controller (tableview) is added to it's container view when the controller is loaded. It also makes sure that if the tableview is already added to the container view it will be removed. All this is done in each specific view controller.
In the view controller of the User Profile view there is an instance of the container view and one of a UIViewController that also acts as a placeholder(named currentViewController from now on). When a specific button is pressed it checks if the an instance of the view controller that we want to display already exists. If not it will make one and will set it's tableview's frame to the bounds of the container view. After that it will remove the currentViewController's view from the superview and the currentViewController itself from the parent viewcontroller to make sure that if there is something assigned to these they will not be there. Then it goes and assigns the desired viewcontroller to the currentViewController. It also assigns the desired viewcontroller's containerView instance to the containerview in the parent viewcontroller (the User Profile viewcontroller). At the end it will add the desired viewcontroller as a child to the main viewcontroller (the User Profile viewcontroller) and desired viewcontroller's view to the containerView of the main viewcontroller.
This is the code for one of the buttons:
//Check if there is an instance of the viewcontroller we want to display. If not make one and set it's tableview frame to the container's view bounds
if(!_userWallViewController) {
self.userWallViewController = [[WallViewController alloc] init];
// self.userWallViewController.activityFeedTableView.frame = self.containerView.bounds;
}
[self.userWallViewController.containerView addSubview:self.userWallViewController.activityFeedTableView];
//If the currentviewcontroller adn it's view are already added to the hierarchy remove them
[self.currentViewController.view removeFromSuperview];
[self.currentViewController removeFromParentViewController];
//Add the desired viewcontroller to the currentviewcontroller
self.currentViewController = self.userWallViewController;
//Pass the data needed for the desired viewcontroller to it's instances
self.userWallViewController.searchURLString = [NSString stringWithFormat:#"event/user/%#/", self.userID];
self.userWallViewController.sendCommentURLString = [NSString stringWithFormat:#"event/message/%#", self.userID];
self.userWallViewController.totalCellHeight = ^(float totalCellHeight){
self.userWallViewController.numberOfCells = ^(float numberOfCells){
NSLog(#"The total number of cells: %f", numberOfCells);
NSLog(#"The total cell height: %f", totalCellHeight);
self.scrollView.contentSize = CGSizeMake(320.0, totalCellHeight + 172.0 + 33.0);
CGRect newFrame = self.userWallViewController.containerView.frame;
newFrame.size.height = totalCellHeight + 33.0;
self.userWallViewController.containerView.frame = newFrame;
NSLog(#"Container view: %f", self.containerView.frame.size.height);
NSLog(#"Scroll view: %f",self.scrollView.contentSize.height );
};
};
//Add this containerview to the desired viewcontroller's containerView
self.userWallViewController.containerView = self.containerView;
//Add the needed viewcontroller and view to the parent viewcontroller and the containerview
[self addChildViewController:self.userWallViewController];
[self.containerView addSubview:self.userWallViewController.view];
[self performSelector:#selector(changeScrollView) withObject:self afterDelay:0.5];
//CLEAN UP THE CONTAINER VIEW BY REMOVING THE PREVIOUS ADDED TABLE VIEWS
[self.userFansViewController.userSimpleTableView removeFromSuperview];
[self.fanOfViewController.userSimpleTableView removeFromSuperview];
[self.userPublishedMovellaListViewController.gridView removeFromSuperview];
[self.userPublishedMovellaListViewController removeFromParentViewController];
self.userPublishedMovellaListViewController = nil;
}
I know this answer is over a year late, but I wanted to state my hypothesis on it...just incase it might help someone else later. Im implementing a similar view and came to this conclusion. Anyone is welcomed to correct me if I'm wrong.
I think that perhaps the top view is a header view and the two options that seem like a collection view and a table view are both collection views.
Because the layout of collection views can be fine tuned to the most minute details, I think the view that looks like a table view is just a really specifically designed collection view. And when switching between the views, the collection view's data and properties are being swapped and reloaded.
I have a container view controller that consists of a navigation view at top, and a content view for the remainder of the screen. The navigation menu consists of several buttons, some of which present a popover with UITableView for secondary navigation. This all worked until I assigned a child view controller and set it's view as subview of the content view. Now, the popover appears, but has nothing inside it (no tableview, just black).
Why is this?
Here's the code I added for the child vc in container view:
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
ContentWebViewController *initialVC = [[ContentWebViewController alloc] init];
[self addChildViewController:initialVC];
initialVC.view.frame = self.view.bounds;
[self.containerView addSubview:initialVC.view];
self.currentController = initial;
}
See the screenshot below. I added a vc with a simple webview showing google (just as a placeholder for now). The popover was working fine before I assigned the child VC.
Maybe it will help other in other cases -
If you are using size classes (probably you are since you are developing this to iPad) -
Design your popover view controller in Any-Any size and it should be OK - after that you can return to your wanted size.
(You can also uninstall the size classes of any object in that view controller instead of redesign the VC)
I somehow (don't ask me how) changed the class that my table view controller was inheriting from. It should have been (obviously) UITableViewController, but was UITableViewController, so initWithStyle was not being called....