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UIRefreshControl - beginRefreshing not working when UITableViewController is inside UINavigationController
(15 answers)
Closed 9 years ago.
I am not able to see the loading spinner when calling beginRefreshing
[self.refreshControl beginRefreshing];
My UITableViewController subclass uses a UIRefreshControl
// refresh
UIRefreshControl * refreshControl = [UIRefreshControl new];
[refreshControl addTarget:self action:#selector(refreshTableView) forControlEvents:UIControlEventValueChanged];
self.refreshControl = refreshControl;
It is working perfectly with user interaction (when the user drops the table down), then the spinner is visible.
But when i call beginRefreshing on viewDidLoad, I don't see the spinner (only when i drag the table down).
Notes:
self.refreshControl reference is right
reloadData or endRefreshing is not called immediately after beginRefreshing, but there is a long time delay (loading data through network), so I am not canceling the beginRefreshing.
Edit :
This only happens when the contentOffset property of the tableView is 0 and i call [self.refreshControl beginRefreshing]. Bug? Feauture?
It looks like a bug to me, because it only occures when the contentOffset property of the tableView is 0
I fixed that with the following code (method for the UITableViewController) :
- (void)beginRefreshingTableView {
[self.refreshControl beginRefreshing];
if (self.tableView.contentOffset.y == 0) {
[UIView animateWithDuration:0.25 delay:0 options:UIViewAnimationOptionBeginFromCurrentState animations:^(void){
self.tableView.contentOffset = CGPointMake(0, -self.refreshControl.frame.size.height);
} completion:^(BOOL finished){
}];
}
}
Your fix looks good, But I don't think this as a bug.
When beginRefreshing method is called manually,
When there is no row / cell available it makes sense for refresh control appearing automatically.
But when there are some cells available, and when we call begin refresh manually (A scenario where we refresh periodically based on timer) then It should not animate / change the content offset as it will distract the user if he is seeing / reading content in some visible cell.
Related
I'm building an app where the first view has a menu panel, and I want this panel to stick around for the life of the app. The only places the user can "go" are reachable via buttons on this panel (a UICollectionView). In case it matters, this app is landscape-only, and iOS 6-only.
In order to make this work I created a custom segue, which removes everything from the view except for the menu panel, then adds the new view controller's view as a subview, sets the new view's frame to the bounds of the superview, and sends the new view to the back (so it's behind the menu panel). I call viewWill/DidDisappear from prepareForSegue, because otherwise they don't get called.
It may sound kludgy (it does to me), but it works fine except for one thing - the new view comes up from the bottom. It looks funny.
I then tried adding my own animation block - I initially locate the view off to the left, then animate it into place. I send it to the back in the completion block for the animation. This seems perfectly logical, and the frame values are all what they should be. But this one is worse - the view comes in from the lower left corner.
Can anyone suggest a way to make this work? Here's my current perform method:
- (void)perform {
MainMenuViewController *sourceVC = (MainMenuViewController *)self.sourceViewController;
UIViewController *destinationVC = (UIViewController *)self.destinationViewController;
for (UIView *subview in [sourceVC.mainView subviews]) {
// don't remove the menu panel or the tab
if (![subview isKindOfClass:[UICollectionView class]] && [subview.gestureRecognizers count] == 0) {
[subview removeFromSuperview];
}
}
[sourceVC.mainView addSubview:destinationVC.view];
CGRect finalFrame = sourceVC.mainView.bounds;
CGRect frame = finalFrame;
frame.origin.x = finalFrame.origin.x - finalFrame.size.width;
destinationVC.view.frame = frame;
[UIView animateWithDuration:0.5 animations:^{
destinationVC.view.frame = finalFrame;
} completion:^(BOOL finished) {
// make sure it ends up behind the main menu panel
[sourceVC.mainView sendSubviewToBack:destinationVC.view];
}];
}
It turned out to be a simple error - I needed to set destinationVC's frame before calling addSubview. Setting it afterwards was triggering the unwanted animation.
I use an instance of UITextField in which the text is normally aligned to the right, but switches to left alignment when being edited. This is done by calling setTextAlignment: on the editingDidBegin event. Since the update to iOS 6 this behaves strangely: The text alignment is changed correctly from right to left, but the cursor remains at the far right of the text field until some input is performed.
Does anybody know how to restore the expected behaviour so that the cursor moves as well when the alignment is changed?
To give some context: I use the text field to show a value with a unit. The unit is removed during editing and then displayed again after the user hits enter.
Method called on event editingDidBegin:
- (IBAction)textEditingDidBegin:(UITextField *)sender
{
[sender setTextAlignment:NSTextAlignmentLeft];
[sender setText:[NSString stringWithFormat:#"%.0f", width]];
}
Method called on event editingDidEnd:
- (IBAction)textEditingDidEnd:(id)sender
{
[sender setTextAlignment:UITextAlignmentRight];
[sender setText:[NSString stringWithFormat:#"%.0f m", width]];
}
Try resigning the textView as first responder, then make it first responder right after that.
textView.textAlignment = NSTextAlignmentCenter;
[textView resignFirstResponder];
[textView becomeFirstResponder];
-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
textField.textAlignment = NSTextAlignmentLeft ;
return YES ;
}
Change the textAlignment before editing did begin. The best place I know to do this is in the UITextFieldDelegate method textFieldShouldBeginEditing.
I have some data that is fetched in another thread that updates a UICollectionView's header. However, I've not found an efficient way of reloading a supplementary view such as a header or footer.
I can call collectionView reloadSections:, but this reloads the entire section which is unnecessary. collectionView reloadItemsAtIndexPaths: only seems to target cells (not supplementary views). And calling setNeedsDisplay on the header itself doesn't appear to work either. Am I missing something?
You can also use (the lazy way)
collectionView.collectionViewLayout.invalidateLayout() // swift
[[_collectionView collectionViewLayout] invalidateLayout] // objc
More complex would be to provide a context
collectionView.collectionViewLayout.invalidateLayout(with: context) // swift
[[_collectionView collectionViewLayout] invalidateLayoutWithContext:context] // objc
You can then make a or configure the context yourself to inform about what should be updated see: UICollectionViewLayoutInvalidationContext
It has a function in there that you can override:
invalidateSupplementaryElements(ofKind:at:) // swift
Another option is (if you have already loaded the correct header/footer/supplementary view) and you only want to update the view with the new data than you can use one of the following functions to retrieve it:
supplementaryView(forElementKind:at:) // get specific one
visibleSupplementaryViews(ofKind:) // all visible ones
Same goes for visible cells with visibleCells. The advantage of just getting the view and not reloading a view entirely is that the cells retains it state. This is espically nice with table view cells when they use swipe to delete/edit/etc since that state is lost after reloading the cell.
If you feel fanatic you can of course also write some extensions to retrieve only cells/supplementary views of a given kind using generics
if let view = supplementaryView(forType: MySupplementaryView.self, at: indexPath) {
configure(view, at indexPath)
}
this assumes that you have a function that registers/dequeues views in example with their class name. I made a post about this here
I just ran into the same problem, and I ended up looking up the view using its tag to edit a label:
UICollectionReusableView *footer = (UICollectionReusableView*)[self.collectionView viewWithTag:999];
UILabel *footerLabel = (UILabel*)[footer viewWithTag:100];
Like you said it is unnecessary to reload an entire section, which cancels out any animation on cells as well. My solution isn't ideal, but it's easy enough.
Swift 3/4/5 version:
collectionView.collectionViewLayout.invalidateLayout()
Caution!
If you change the number of collectionView items at the same time (for example you show the footer only if all cells were loaded), it will crash. You need to reload the data first, to make sure that the number of items is the same before and after invalidateLayout():
collectionView.reloadData()
collectionView.collectionViewLayout.invalidateLayout()
I got the same problem. I tried #BobVorks's answer and it is working fine, if only the cell was reused else it won't. So, I tried finding a more cleaner way to achieve this and I came up reloading the whole UICollectionView after the performBatchUpdate (completion block) and it is working great. It reloads the Collection Without any cancellation of animation in the insertItemsAtIndexPath. Actually I personally up voted recent 2 answers cause i find it working but in my case, this is the cleanest way to do it.
[self.collectionView performBatchUpdates:^{
// perform indexpaths insertion
} completion:^(BOOL finished) {
[self.collectionView reloadData];
}];
[UIView performWithoutAnimation:^{
[self.collectionView reloadSections:[NSIndexSet indexSetWithIndex:4]];
}];
[UIView performWithoutAnimation:^{
[self.collectionView reloadData];
}];
Here are two ways you could do it.
1.
Create a mutable model to back the data that will eventually be available. Use KVO in inherited class of UICollectionReusableView to observe the changes and update the header view with the new data as it comes available.
[model addObserver:headerView
forKeyPath:#"path_To_Header_Data_I_care_about"
options:(NSKeyValueObservingOptionNew |
NSKeyValueObservingOptionOld)
context:NULL];
then implement listener method in header view
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
2.
add notification listener to the view and post a notification when the data has successfully come available. Downside is that this is application wide and not a clean design.
// place in shared header file
#define HEADER_DATA_AVAILABLE #"Header Data Available Notification Name"
// object can contain userData property which could hole data needed.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(headerDataAvailable:) name:HEADER_DATA_AVAILABLE object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:HEADER_DATA_AVAILABLE object:nil];
let headerView = collectionView.visibleSupplementaryViews(ofKind: UICollectionView.elementKindSectionHeader)[0] as! UICollectionReusableView
I've used above method to get current header, and successfully updated subviews on it.
Here's what I did to update only the section headers that are currently loaded in memory:
Add a weakToStrong NSMapTable. When you create a header, add the header as the weakly held key, with the indexPath object. If we reuse the header we'll update the indexPath.
When you need to update the headers, you can now enumerate the objects/keys from the NSMapTable as needed.
#interface YourCVController ()
#property (nonatomic, strong) NSMapTable *sectionHeaders;
#end
#implementation YourCVContoller
- (void)viewDidLoad {
[super viewDidLoad];
// This will weakly hold on to the KEYS and strongly hold on to the OBJECTS
// keys == HeaderView, object == indexPath
self.sectionHeaders = [NSMapTable weakToStrongObjectsMapTable];
}
// Creating a Header. Shove it into our map so we can update on the fly
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
PresentationSectionHeader *header = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:#"presentationHeader" forIndexPath:indexPath];
// Shove data into header here
...
// Use header as our weak key. If it goes away we don't care about it
// Set indexPath as object so we can easily find our indexPath if we need it
[self.sectionHeaders setObject:indexPath forKey:header];
return header;
}
// Update Received, need to update our headers
- (void) updateHeaders {
NSEnumerator *enumerator = self.sectionHeaders.keyEnumerator;
PresentationSectionHeader *header = nil;
while ((header = enumerator.nextObject)) {
// Update the header as needed here
NSIndexPath *indexPath = [self.sectionHeaders objectForKey:header];
}
}
#end
This question is very old but a simple way to do it is to just set a delay that covers the time your view is animating and disabling the animation while you update the view...usually a delete or insert takes about .35 seconds so just do:
delay(0.35){
UIView.performWithoutAnimation{
self.collectionView.reloadSections(NSIndexSet(index: 1))
}
My problem arose when frame sizes for the supplementary views changed upon invalidating the layout. It appeared that the supplementary views were not refreshing. It turns out they were, but I was building the UICollectionReusableView objects programmatically, and I was not removing the old UILabel subviews. So when the collection view dequeued each header view, the UILabels would pile up, causing erratic appearance.
The solution was to build each UICollectionReusableView completely inside the viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath method, starting by a) removing all subviews from the dequeued cell, then b) getting the frame size from the item's layout attributes to allow adding the new subviews.
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
yourClass *header = (yourClass *)[collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:#"identifier" forIndexPath:indexPath];
[[header viewWithTag:1] removeFromSuperview]; // remove additional subviews as required
UICollectionViewLayoutAttributes *attributes = [collectionView layoutAttributesForSupplementaryElementOfKind:kind atIndexPath:indexPath];
CGRect frame = attributes.frame;
UILabel *label = [[UILabel alloc] initWithFrame: // CGRectMake based on header frame
label.tag = 1;
[header addSubview:label];
// configure label
return header;
}
I have got a Perfect solution:
let footerView = self.collectionView.visibleSupplementaryViews(ofKind: UICollectionView.elementKindSectionFooter)
Now you can access all subview of footerView by using:
footerView[0].subviews[0]
If you have label in your footerView then :
let label: UILabel = footerView[0].subviews[0] as? UILabel ?? UILabel()
Final Step:
label.text = "Successfully Updated Footer."
if let footerView = collectionView.subviews.first(where: {$0 is LoadingFooterCell}) as? LoadingFooterCell {
footerView.isLoading = .loading
}
I want to implement pull-down-to-refresh in a UICollectionViewController under iOS 6. This was easy to achieve with a UITableViewController, like so:
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:#selector(startRefresh:)
forControlEvents:UIControlEventValueChanged];
self.refreshControl = refreshControl;
The above implements a nice liquid-drop animation as part of a native widget.
As UICollectionViewController is a "more evolved" UITableViewController one would expect somewhat of a parity of features, but I can't find a reference anywhere to a built-in way to implement this.
Is there a simple way to do this that I'm overlooking?
Can UIRefreshControl be used somehow with UICollectionViewController despite the header and docs both stating that it's meant to be used with a table view?
The answers to both (1) and (2) are yes.
Simply add a UIRefreshControl instance as a subview of .collectionView and it just works.
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:#selector(startRefresh:)
forControlEvents:UIControlEventValueChanged];
[self.collectionView addSubview:refreshControl];
That's it! I wish this had been mentioned in the documentation somewhere, even though sometimes a simple experiment does the trick.
EDIT: this solution won't work if the collection is not big enough to have an active scrollbar. If you add this statement,
self.collectionView.alwaysBounceVertical = YES;
then everything works perfectly. This fix taken from another post on the same topic (referenced in a comment in the other posted answer).
I was looking for the same solution, but in Swift. Based on the above answer, I have done the following:
let refreshCtrl = UIRefreshControl()
...
refreshCtrl.addTarget(self, action: "startRefresh", forControlEvents: .ValueChanged)
collectionView?.addSubview(refreshCtrl)
Not forgetting to:
refreshCtrl.endRefreshing()
I was using Storyboard and setting self.collectionView.alwaysBounceVertical = YES; did not work. Selecting the Bounces and Bounces Vertically does the job for me.
The refreshControl property has now been added to UIScrollView as of iOS 10 so you can set the refresh control directly on collection views.
https://developer.apple.com/reference/uikit/uiscrollview/2127691-refreshcontrol
UIRefreshControl *refreshControl = [UIRefreshControl new];
[refreshControl addTarget:self action:#selector(refreshControlAction:) forControlEvents:UIControlEventValueChanged];
self.collectionView.refreshControl = refreshControl;
mjh's answer is correct.
I ran into the issue where if the the collectionView.contentSize was not larger then the collectionView.frame.size, you can not get the collectionView to scroll. You can not set the contentSize property either (at least I couldn't).
If it can't scroll, it won't let you do the pull to refresh.
My solution was to subclass UICollectionViewFlowLayout and overide the method:
- (CGSize)collectionViewContentSize
{
CGFloat height = [super collectionViewContentSize].height;
// Always returns a contentSize larger then frame so it can scroll and UIRefreshControl will work
if (height < self.collectionView.bounds.size.height) {
height = self.collectionView.bounds.size.height + 1;
}
return CGSizeMake([super collectionViewContentSize].width, height);
}
I want to display a MPMoviePlayerViewController in full screen mode, but when the fullscreen button of the movieplayercontroller view is beeing pressed, first the MPMoviePlayerWillEnterFullscreenNotification gets called, as expacted, but than the MPMoviePlayerPlaybackDidFinishNotification is also beeing sent. As a reason it says MPMovieFinishReasonPlaybackEnded and i don't know, what i'm doing wrong. (In addition, i use iOS 6.0 and XCode 4.5.1)
My expactations are, that only the MPMoviePlayerWillEnterFullscreenNotification is beeing called.
Short explanation to the code below:
The MovieplayerViewController's view is beeing displayed in a tiny subview in my content view. When tapping the fullscreen-button, it first gets displayed as fullscreen but than also calls the exit button and stops playing (no crashes, nothing else).
MPMoviePlayerViewController *playerViewController = [[MPMoviePlayerViewController alloc] initWithContentURL:url];
[playerViewController.moviePlayer setControlStyle:MPMovieControlStyleEmbedded];
[playerViewController.moviePlayer setScalingMode:MPMovieScalingModeFill];
CGRect rect = videoView.frame;
rect.origin = CGPointZero;
[playerViewController.view setFrame:rect];
[playerViewController.moviePlayer prepareToPlay];
//movie this is my contents subview, where i add the viewcontroller's view as a subbview
[self.videoView addSubview:playerViewController.view];
[self.videoView setHidden:NO];
playerViewController.moviePlayer.useApplicationAudioSession = NO;
[playerViewController.moviePlayer play];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(moviePlayerDidFinishNotification:)
name:MPMoviePlayerPlaybackDidFinishNotification
object:playerViewController.moviePlayer];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(moviePlayerWillEnterFullscreenNotification:)
name:MPMoviePlayerWillEnterFullscreenNotification
object:playerViewController.moviePlayer];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(moviePlayerWillExitFullscreenNotification:)
name:MPMoviePlayerWillExitFullscreenNotification
object:playerViewController.moviePlayer];
//i store the movieplayer in a property, so i can use it for further operations
self.myPlayer = playerViewController;
[playerViewController release];
And thats it!
When the resize (or fullscreen) button is being pressed, the moviePlayerDidFinishNotification: method also is being called
- (void)moviePlayerDidFinishNotification:(NSNotification*) aNotification {
int reason = [[[aNotification userInfo] valueForKey:MPMoviePlayerPlaybackDidFinishReasonUserInfoKey] intValue];
if (reason == MPMovieFinishReasonPlaybackEnded) {
//movie finished playin
//in debug mode, it stops right at the NSLog
NSLog(#"");
}
else if (reason == MPMovieFinishReasonUserExited) {
//user hit the done button
}
else if (reason == MPMovieFinishReasonPlaybackError) {
//error
}
.. }
Is there something i do wrong or is there probably a change since iOS 6.0?
Ok, seems to be that there are some problems in the MPMoviePlayerViewController. What helped is to simply us the MPMoviePlayerController only.
For future reference the reason that your player showed in a small window was because you were setting:
[playerViewController.moviePlayer setControlStyle:MPMovieControlStyleEmbedded];
[playerViewController.moviePlayer setScalingMode:MPMovieScalingModeFill];
CGRect rect = videoView.frame;
rect.origin = CGPointZero;
[playerViewController.view setFrame:rect];
[playerViewController.moviePlayer prepareToPlay];
//movie this is my contents subview, where i add the viewcontroller's view as a subbview
[self.videoView addSubview:playerViewController.view];
[self.videoView setHidden:NO];
When you use an MPMoviePlayerViewController it creates it's own view controller. These calls are not necessary and will only create bizarre behavior. That's why the MPMoviePlayerController worked properly because it's designed to work inside another view controller.