I'm having a problem adjusting a parent view's layout when orientation changes for it's child view. I have a collection view controller that, when one of the cells are tapped, pushes a child view on top. If an orientation change occurs while the child view is visible and it is dismissed, the parent view's collection view cells haven't adjusted for the new width.
I should note that this works fine if the parent view is visible.
The only thing that has fixed this for me is in the viewDidAppear method of the parent view controller invalidates the collection view layout, but for me it's too late as the user sees the animation of the collection view cells snap into place.
- (void) viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[self.collectionView.collectionViewLayout invalidateLayout];
[self.collectionView reloadData];
}
I would have preferred to use viewWillAppear, but that doesn't seem to do anything. It sounds like it can only adjust the cells when the parent view is visible.
Is there a way around this?
Referring to this answer, iOS does not send orientation change events to offscreen view controllers, making them an unreliable way to determine whether the view has been resized.
viewWillAppear: isn't working in your case because iOS doesn't resize the offscreen view controller's view until after it calls the method, so your invalidate and reload are being pulled off the wrong values.
I believe the iOS8+ viewWillTransitionToSize:withTransitionCoordinator: method fires even when offscreen, but I'm not positive. In my experience, the size it provides does not reflect the actual size of the view. What I personally like to hook into is viewWillLayoutSubviews, usually guarded with a width check:
#property (nonatomic) CGFloat lastWidth;
- (void)viewWillLayoutSubviews
{
[super viewWillLayoutSubviews];
if (self.lastWidth != CGRectGetWidth(self.view.bounds)) {
self.lastWidth = CGRectGetWidth(self.view.bounds);
// Update your collection view here.
}
}
This way, whenever your view is going to resize (on display, inside an orientation change animation) you can update the size information.
try overriding -(void)viewWillLayoutSubviews: method in your parent view controller. In your case,it goes like this
-(void)viewWillLayoutSubviews {
[self.collectionView.collectionViewLayout invalidateLayout];[self.collectionView reloadData];
}
You could try invalidating your layout and reloading in the rotation handler methods.
For pre-iOS 8
willRotateToInterfaceOrientation:duration:
And for iOS 8+
viewWillTransitionToSize:withTransitionCoordinator:
Related
Am using xib to design my view using auto layout.Run time I want to change the content size of my scrollview in viewDidLayoutSubviews method but its not working.On orientation change the code written inside viewDidLayoutSubviews works but on load its not working.Please advice what could be the issue?
- (void)viewDidLayoutSubviews
{
scroll.contentSize = CGSizeMake(scroll.frame.size.width, attBtn.frame.origin.y+attBtn.frame.size.height+40);//atnBtn is added programatically
}
Usually when you want to have a view redraw you should call:
[self setNeedsDisplay: YES];
Granted I have never build on iOS, on OSX this code works every time. Also, for example, if you want your delegate to call a redraw for a view named someView:
[someView setNeedsDisplay: YES];
So, I want to do some basic animations of labels and later views.
I have a label, I'm trying to get it to move when a view loads, so I call the following method at the end of viewDidLoad:
- (void)animateView {
NSLog(#"animateView");
[UIView animateWithDuration:20 animations:^{
// set new position of label which it will animate to
self.dcFirstRunDaysLabel.frame = CGRectMake(20,320,280,215);
}];
}
Instead of animating, the label appears in position.
I've tried every tutorial and read through the docs. I get no errors.
Any thoughts?
Cheers.
Try calling your animateView method in viewDidAppear. Because in viewDidLoad your view isn't visible yet.
viewDidLoad:
Called after the controller’s view is loaded into memory.
viewDidAppear:
Notifies the view controller that its view was added to a view hierarchy.
So I realized this myself and found this answer to confirm:
Prevent contentSizeForViewInPopover from animating
Basically I am in a similar boat in that I want to dynamically resize my popover, depending on how much data I have to display. I am also getting this animation action where the popover view moves into place. The problem is, I can't set the popover's content size in the caller/parent, because neither the size of the content view for the text view nor the frame for the text view in my popover is known until viewDidAppear or viewDidLayoutSubviews is called, but of course at this point it's too late, the popover is already on its way to being visible, thus I am getting this unwanted animation.
I am dynamically setting the size of the text views in the popover view controller class to fit the amount of data the text views are displaying, and this only works at the point where their frame size is defined/known/however you want to word it when it hasn't gotten to that point yet in the view lifecycle.
I should mention that I have my view controllers and view all done in a storyboard.
Does this make sense? Hope I'm explaining it well. Any help or suggestions greatly appreciated.
EDIT Here is my viewDidLayoutSubviews method from the view controller I am loading in the popover - hopefully this makes it clear. The first time this loads, if I don't do this in viewDidLayoutSubviews or viewDidAppear the frame for my 2 text views are CGRectZero, the text views don't resize for the content correctly and the popover size isn't right either:
- (void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
self.physicianDataNewValueTextView.text = self.physicianDataNewValue;
CGRect frame = self.physicianDataNewValueTextView.frame;
frame.size.height = self.physicianDataNewValueTextView.contentSize.height;
self.physicianDataNewValueTextView.frame = frame;
self.physicianDataOldValueTextView.text = self.physicianDataOldValue;
frame = self.physicianDataOldValueTextView.frame;
frame.size.height = self.physicianDataOldValueTextView.contentSize.height;
self.physicianDataOldValueTextView.frame = frame;
self.contentSizeForViewInPopover = CGSizeMake(384.0f, self.physicianDataOldValueTextView.frame.size.height + 75.0f);
}
So I decided to use delegation. Instead of resetting the content size in the view controller for the popover, I call my delegate (which is the containing view controller) with the new size so I can set it there with the animated property set to NO. Works well.
In my iPad app I have an UITableView. Table's frame size is less than screen size, so to make search functionality look nice I have to adjust searchResultTableView's frame to fit my TableView. I'm doing it in my UISearchDisplayDelegate's -searchDisplayController:willShowSearchResultsTableView: method.
Everything works fine except dimming view. When I'm starting search dimming view's width is equal to screen width:
When I start entering search string or clear textfield my searchResultsTableView resizes properly and everything works as it should:
I tried to change searchResultsTableView frame inside -searchDisplayControllerWillBeginSearch: method using this line
controller.searchResultsTableView.frame = myFrame;
but it doesn't work as well. Any suggestions besides implementing my own search display controller?
I also needed to change the frame of the dimming view but for a different reason. In my case I created a UISearchDisplayController and UISearchBar programmatically in a regular UIViewController not a UITableViewController. I was also using MFSideMenu which added to the complexity of the problem. What ended up happening was the dimming view was in the correct position initially but the next time the search was cleared the dimming view shifted leftwards and upwards by exactly half of it's size. Given the UISearchDisplayController you can find the dimming view like so.
for(UIView * v in controller.searchContentsController.view.subviews)
{
if([v isMemberOfClass:[UIControl class]])
{
v.frame = newFrame; //This frame should account for the UISearchBar
}
}
To handle for the initial incorrect frame you should change it in this delegate method:
- (void) searchDisplayController:(UISearchDisplayController *)controller didShowSearchResultsTableView:(UITableView *)tableView;
To handle for an incorrect frame on any subsequent clears you should change it in this delegate method:
- (void) searchDisplayController:(UISearchDisplayController *)controller didHideSearchResultsTableView:(UITableView *)tableView;
Note: this solution runs through the subviews of the searchContentsController which is one of the reasons I used isMemberOfClass instead of isKindOfClass (UIButton is a subclass of UIControl). Further discrimination would be required if you added a UIControl instance into your view (you could use tags to help determine which ones are yours).
I have a problem with my table view. When dismissing a modal view controller presented on top of it, it always scrolling to the top . I have tried observing the changes to contentOffset using KVO, but the one that messes my view goes behind it.
From the UITableViewController, when user finishes his task in the modal dialog, self.tableView.contentOffset is , I call:
[self dismissModalViewControllerAnimated:YES]
Subsequently, when the viewWillAppear:(BOOL)animated is called, the self.tableView.contentOffset is already set to 0,0.
Is this supposed to be happening? I am able to work around the issue by remembering the scroll position before presenting the modal view and restore it back in viewWillAppear after dismissing the modal view. But it seems wrong. Am I missing something?
I have found similar problem described in Dismiss modal view changes underlying UIScrollView.
It looks like this is default behavior of UITableViewController. I tested it in very simple app and It worked exactly as you said. If you don't like it, use UIViewController instead.
Here is how I work around this problem, so that the table view maintains the original scroll position. In my subclass of UITableViewController I have added:
#property (assign) CGPoint lastScrollPosition;
Then in the implementation, I have overridden the following:
- (void)viewWillAppear:(BOOL)animated
{
self.tableView.contentOffset = self.lastScrollPosition;
}
- (void)dismissModalViewControllerAnimated:(BOOL)animated
{
self.lastScrollPosition = self.tableView.contentOffset;
[super dismissModalViewControllerAnimated:animated];
}
If you want your table to initially appear scrolled to non-zero position, as I did, don't forget to initialize the lastScrollPosition in your viewDidLoad.