For some reason, my UICollectionView animates the transition inside the visible cell when calling reloadData.
From what I understood it shouldn't do that, and that's what I am trying to do.
Why would the collection view animate on reload data? And how could I stop it?
I will be eventually using [UIView setAnimationsEnabled:YES/NO], but I would be hoping to fix it without too much extra code.
[UIView performWithoutAnimation:^{
[self.collectionView reloadSections:[NSIndexSet indexSetWithIndex:0]];
}];
Related
I have UICollectionView cells with a rounded button inside, when I perform reloadData every rounded button goes from the left to the right. To avoid it, I'm using:
[UIView performWithoutAnimation:^{
[self.collectionView reloadData];
}];
but it doesn't seem to work anymore on iOS 14, can someone help me?
This is the correct way to do it:
[UIView performWithoutAnimation:^{
[self.collectionView reloadData];
[self.collectionView layoutIfNeeded];
}];
I need to reload tableview, but in somehow I want to keep the scroll position. Any way to do it? Maybe store content offset and in viewDidLayoutSubviews I should reset it?
TableView does not reset scroll position. It maintains content offset even after reloadData function is called. So no need to do anything, if you want to keep pixel position.
If you are changing row height at the time of reloading data or changing datasource then you can use scrollToRowAtIndexPath:atScrollPosition:animated: method.
You can save your current offset before reloading the table use this method to save your current offset
self.tableView.contentOffset.y
Or you can Reload like this it will Reload your table from your current Offset
Try this:
[UIView animateWithDuration:0.1 delay:0 options:0 animations:^{
self.tableView.contentOffset = CGPointMake(0, currentOffset);
} completion:^(BOOL finished) {
[self.tableView reloadData];
}];
After reloading the table view you need to call the TableView's method scrollToRowAtIndexPath:atScrollPosition:animated:
Just provide the index path, scroll position which could be one of the following
UITableViewScrollPositionNone,
UITableViewScrollPositionTop,
UITableViewScrollPositionMiddle,
UITableViewScrollPositionBottom
and YES/ NO in animated parameter.
just call scrollToRowAtIndexPath:atScrollPosition:animated: before you use reloadData (with animation:NO)
Also, be carefull in case you have less cells in the updated tableview to prevent crashes.
Hope it helps
It has been suggested that one scroll to the desired row in viewWillAppear, but this does not work with iOS 7. I have only been able to make this work in iOS 7 in the viewDidAppear callback. Unfortunately, you see the desired row scroll into view. I don't want to see any scrolling, I simply want the row to be visible when loaded. Can anyone suggest the proper way to do this in iOS 7?
It probably did not work in viewWillAppear, because that table had no data at this point.
Add [tableView reloadData];and it should work.
Let me get this straight: you want your table view to show a certain row at the top when the view apperas? Yes?
If so, you want:
- (void)scrollToRowAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UITableViewScrollPosition)scrollPosition animated:(BOOL)animated
with your cell indexPath, UITableViewScrollPositionTop as scrollPosition and animated NO like so
[tableView scrollToRowAtIndexPath:myExampleindexPath atScrollPosition:UITableViewScrollPositionTop animated:NO];
If you know the cell index then it's as simple as:
[tableView setContentOffset:CGPointMake(cellLocation.x,cellLocation.y) animated:NO];
Call that just after you load your tableView data and it will scroll to your cell being on top. There are other options as well:
[tableView selectRowAtIndexPath:[NSIndexPath indexPathForRow:currentRow inSection:currentSection] animated:NO scrollPosition:UITableViewScrollPositionTop];
Use this code with whatever scrollPosition you would like and Apple takes care of the bounding to the table (whereas setting the scrolling position is all user defined, it could be out of the table's view).
EDIT:
You could surround your selecting code with a call to UIView setting no animations allowed. That has worked for me in the past with different things, but I have never tried it in viewDidLoad.
[UIView setAnimationsEnabled:NO];
//Scroll the tableview
[UIView setAnimationsEnabled:YES];
I have a timer that fires every second to refresh data on a UICollectionView cell, sometimes (especially when I rotate the device), the cell starts to blink every second. I want to stop this blink animation. However, I have another animation going on inside the collection view cell, so I don't want to disable all animations on it as this code does:
[UIView setAnimationsEnabled:NO];
[collectionView performBatchUpdates:^{
[collectionView reloadItemsAtIndexPaths:indexPaths];
} completion:^(BOOL finished) {
[UIView setAnimationsEnabled:YES];
}];
If you don't want animation on reloading collection view, why don't you just call
[collectionView reloadData];
It only reloads all visible cells.
For the animation inside of the collection view cell, why not code more in the cell object?
How can I cause action to be taken upon completion of a UITableview's animation?
I'm attempting to shrink a UITableview cell and remove a subview of the cell that's not visible after the shrinkage. To shrink the cell, I'm calling [tableview beginUpdates] and [tableview endUpdates], and changing the height of the cell as returned by theheightForRowAtIndexPath datasource method of the UITableview.
The challenge is, i need the tableview to complete shrinking so the subview is out of sight before I can remove the subview. if I put the code to remove the subview from the cell right after (or before or between) the to call [tableview endUpdates] then the subview is removed too soon (it doesn't wait for the animation) and it looks funny.
My thought is i'd like to be able to setup a callback that runs upon completion of the animation, and remove the subView in the callback
What about this?
[CATransaction begin];
[CATransaction setCompletionBlock:^{
// animation has finished
}];
[tableView beginUpdates];
// shrink the cells
[tableView endUpdates];
[CATransaction commit];
Try Using NSNotifications class. Post Notifications when something is about to happen, and later after something has happened. You can use a bool in the same notification method to toggle between 'about to happen' and 'has happened'.