I have a custom view class derived from MKMapView which is overlapped at the top from an UINavigationBar to get this translucent style. I found out i must implement inside the UIViewController the TopLayoutGuide to move the top compass subview from the MKMapView in its right position to be visible. This works perfect, but i also have a custom subview inside my view and i cant figure out how i get the new top offset from the UIViewController from inside the View to position my subview correctly. How did Apple this magic for their subviews inside MKMapView?
I found a way to get the top layout guide position within an UIView to reposition subviews correctly
- (void)layoutSubviews
{
UIViewController *myController = (UIViewController*)[self nextResponder];
CGFloat top = myController.topLayoutGuide.length;
// reposition subviews
// ...
}
Related
What is the best approach for attaching a UIButton on top of UIScrollView or UITableView so when the view is scrolled, the button stays in its place.
Here examples below:
UIButton stays in the right bottom corner when the view is scrolled.
google+ app example
yahoo mail app example
I think this should work. Lay Out your button in a view that is outside of the tableviewcontroller. Then drag an outlet to the tableviewcontroller file. Then add it in code. This code would hold it at the top of the screen.
#IBOutlet var buttonView: UIView!
override func viewDidLayoutSubviews() {
self.view.addSubview(buttonView)
}
override func scrollViewDidScroll(scrollView: UIScrollView) {
var rect = self.buttonView.frame
rect.origin.y = max(0,scrollView.contentOffset.y + scrollView.contentInset.top)
self.buttonView.frame = rect
}
Thank you all for great answers!
I got it worked through storyboard by moving the button from scrollView to View itself. That way it's attached on UIView and it's independent of scrollview.
storyboard snapshot
So now the structure is:
- View
- ScrollView
- Button
Before it was:
- View
- ScrollView
- Button
There are many ways to go about doing this but two that I use most often are as follows.
One approach is embedding the view controller within a navigation controller. This will set a bar on the top and bottom if you choose that you can place bar button items upon.
Another approach is to place a UIView along the top and snap the constraints to the left, right, and top with 0 no-margin. Then set the height. I usually use 40px for the height but you can use what is applicable to your needs. After that you can place a button in that UIView and then set constraints on it to keep in in place.
In my experience, this isn't reliably possible to do with the scrollView itself.
My solution is usually to put anything that needs to float above the tableView/scrollView in a plain ViewController that also contains the tableView/scrollView parent.
If you're using storyboards with a UITableViewController scene, this will likely mean you need to use another scene with UIViewController with a container that has your UITableViewController.
For UITableView use tableHeaderView. For UIScrollView you need to create a separate view not in the scroll view's hierarchy.
Another solution is to put your UIButton in a UIToolbar, and then make the toolbar a child of the UINavigationController's view. After that, in viewDidLayoutSubviews, you can set the rect of the toolbar to sit just below the navigation bar and offset the top of the UIScrollView or UITableView.
Add button which you want in the storyboard.
Design your scrollview
self.view.sendSubviewToBack(scrollViewObj)(in the code)
This worked for me.
I have a UIScrollView that contains a bunch of view controllers, and in each view controller there is a button that if pressed, should scroll the UIScrollView to a certain position. How do I go about connecting the viewController IBAction for the button to set the scroll position of the UIScrollView?
I know I'll call contentOffset at some point, but I'm struggling with getting the ViewControllers to control the Scroll View.
One way you could do it... When you add each UIViewController.view to the UIScrollView you could also set a var in each UIViewController that references the UIScrollView.
For example, for some UIViewController, we'll call it X, put
var scrollView: UIScrollView?
in it. Then in your class that controls the UIScrollView, when you add view X to the UIScrollView, also do the following:
viewControllerX.scrollView = self.theScrollView
Now, when your IBAction method is called in viewControllerX, you have a reference to the UIScrollView and as you said, can do self.scrollView.contentOffset.y = someValueHere to change its position.
I'm working on a UITableViewController. I have to display a view with some info, that view will be added to the TableViewController programatically. This is my code of adding it:
MyNotificationView *notificationView = // some initializations;
[self.view addSubview:notificationView]; // self is the UITableViewController
notificationView.center = self.view.center;
However on UITableViewController, this code actually sets the center of my notificationView to the center of the scrollable area of the TableViewController, and my notificationView scrolls as the TableView scrolls.
What I want is to add my notificationView to the screen center and stick it there, so how can this be done?
You can make a UIViewController with an UITableView inside and the notificationView you want to keep in center, just add it to view [self.view addSubview:notificationView];
I implemented a custom UIViewController Transition in my App, which replaces the navigation controllers built in push animation.
Everything works so far, except the toplayoutguide in the newly pushed view controller is 0 although the new view controller inherited the navigation bar from the old view controller.
It should be 64.0 (Statusbar height + Navigation bar height), where it is 0.0 now.
So all objects, which are attached to the top layout guide in the storyboard now appear 64 points too high (below the translucent bar).
When I disable the custom View Transition the top layout guide will have the expected value.
I tried to call layoutSubviews and updateConstraints "all over the place". In the view controller as well as in the navigationcontroller.
As I understand the navigationcontroller (parentviewcontroller) should update the toplayoutguide of the new view controller, but apparently I am missing something in my custom transitioning code, which triggers the update to the correct value for the toplayoutguide.
Here's my custom transition code which is an object set as delegate of the navigationcontroller:
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
return 0.7;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIView *animationContainerView = [transitionContext containerView];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *toView = [toVC view];
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIView *fromView = [fromVC view];
CGRect endFrame = [transitionContext finalFrameForViewController:toVC];
CGRect startFrame;
startFrame = CGRectOffset(endFrame, 0, endFrame.size.height);
if (self.operation == UINavigationControllerOperationPop) {
[animationContainerView insertSubview:toView belowSubview:fromView];
[toView setFrame:endFrame];
}
else{
[toView setFrame:startFrame];
[animationContainerView insertSubview:toView aboveSubview:fromView];
}
[UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 usingSpringWithDamping:0.7 initialSpringVelocity:0.8 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
if (self.operation == UINavigationControllerOperationPop) {
[fromView setFrame:startFrame];
[fromView layoutIfNeeded];
}
else{
[toView setFrame:endFrame];
[toView layoutIfNeeded];
}
} completion:^(BOOL finished) {
[transitionContext completeTransition:YES];
}];
}
Nothing really fancy happens there. Just the view sliding from the bottom up with some built in dynamics.
The problem is, that the objects attached to the top layout guide now are under the navigation bar, as the top layout guide length == 0.
I can't figure out what I need to do, so that the view controller's toplayoutguide is set to the correct value.
The push navigation is performed "plain vanilla" with a push storyboard segue. All I do, before calling performSegueWithIdentifier is to set the navigationcontrollers delegate.
Here's the code:
self.navigationController.delegate = [[My_CustomNavigationTransitionDelegate alloc] init];
[self performSegueWithIdentifier:#"infosSegue" sender:nil];
What do I miss?
I was having an issue where the bottomLayoutGuide property would set itself to zero length and then would cause my buttons above the tab bar to fall below to tab bar with the autolayout.
Have you looked at doing this
[self.navigationController.view setNeedsLayout]
I put it into my viewwillappear and I stopped getting a zero length on the bottomLayoutGuide property. Maybe that would help you out with your topLayoutGuide property too.
I was able to work around this, with the following view hierarchy:
UIView
UIScrollView
<content, constrained to UIScrollView>
Constrain the UIScrollView to match the UIView's top, leading, trailing, and bottom edges. Interface Builder might want you to use the topLayoutGuide and bottomLayoutGuide for the UIScrollView, or it might not. Maybe it's dependent on the version of Xcode, but some of our View Controllers used the superview, others used the layout guides.
For the views where Interface Builder didn't want to constraint the scroll view relative to its superview, I opened the storyboard in a text editor and adjusted the constraints on the scroll view by hand.
Finally, on the View Controller, make sure that extend edges under top bar is YES, and so is Adjust Scroll View Insets.
Basically, I'm avoiding using the topLayoutGuide, and instead relying on the scroll view insets, which does work.
Where I didn't have a UIScrollView in the hierarchy, like you, NOT extending edges under the top bar worked for me.
I ran into the exact same problem. My custom navigation controller's container view didn't have constraints. The minute I added vertical spacing constraints from the container view to its superview's layout guides (albeit the two were identical in size), and set the top/bottom/status bar appearance on the container view everything was ok and the layout guides of the pushed controllers were in the correct position. Hope that helps.
Update: From the official documentation on topLayoutGuide
A view controller within a container view controller does not set this property's value. Instead, the container view controller constrains the value to indicate:
The bottom of the navigation bar, if a navigation bar is visible
The bottom of the status bar, if only a status bar is visible
The top edge of the view controller’s view, if neither a status bar nor navigation bar is visible
So the container view needs to implement correct constraints and hide/show bars and such for the effects to work. AFAIK there is no API to do this in custom container view controllers.
I found a way. First uncheck "Extend Edges" property of controller after that navigation bar will get in dark color. Add a view to controller and set top and bottom LayoutConstraint -100. Then make view's clipsubview property no (for navigaionbar transculent effect). My english is bad sorry for that. :)
I am trying to add a hovering subview to a UIPopoverController. I have a table view controller as a content view controller inside the popover. I tried to add it as a normal subview:
UIPopoverController* popoverController = [[UIPopoverController alloc] initWithContentViewController:myTableViewController];
UIView* mySubview = ...
[popoverController.contentViewController.view addSubview:mySubView];
It is displayed correctly but unfortunately scrolls up and down with the table view. I would like to have its position fixed.
I also tried to update the position of the subview by the y offset of the scrollview in the scrollViewDidScroll: method of the table view controller, but would like to avoid this solution if possible.
You have to make the content controller a UIViewController subclass rather than a UITableViewController subclass.