I found out, that UITableView modify contentSize property and I can't set it by myself.
This is my call stack. After this call contentSize is modified. I don't want it, because of that I want to hide header, so I need to scroll view a little bit down, and to make it I set contentSize little higher than visible to be able to scroll down a bit.
Any ideas how to hide table header, and keep it hidden after insertion/deletion ? By hide I mean table header initially "hidden" but show up when you scroll to the top.
I'm using NSFetchedResultsController to fetch data with CoreData.
You can implement the tableview delegate methods for the size of header and return 0. it would like this:
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{
return 0;
}
This would set the header for each section to be zero. You can also edit the footer size in the same fashion with heightForFooterInSection:
Looks like contentSize is modified by iOS private code just after controllerDidChangeContent is called.
Just for record. This is my solution (searchView is view that I want to hide):
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentSize.height <= scrollView.frame.size.height)
{
[scrollView setContentOffset:CGPointMake(0, self.searchView.frame.size.height)];
[scrollView setContentSize:CGSizeMake(scrollView.contentSize.width, tableView.frame.size.height + self.searchView.frame.size.height)];
}
}
Related
I have two table views set up side by side, and I need them to scroll at exactly the same time. So, when you scroll one, the other one will scroll at the same time.
I did some searching and I couldn't find any information, but I assume it must be possible somehow.
My table views are both connected to the same class and I differentiate between them like this:
if tableView == tableView1 {
//
} else if tableView = tableView2 {
//
}
You can get set the scrollView delegate to self on both of your tableView's scrollViews. And in -scrollViewDidScroll, take the contentOffset and set the other scrollView's contentOffset to the same value.
Like Schemetrical said you should use scrollViewDidScroll.
see the first answer of this:
Scrolling two UITableViews together
- (void)scrollViewDidScroll:(UIScrollView *)scrollView;
{
UITableView *slaveTable = nil;
if (self.table1 == scrollView) {
slaveTable = self.table2;
} else if (self.table2 == scrollView) {
slaveTable = self.table1;
}
[slaveTable setContentOffset:scrollView.contentOffset];
}
If you want them to scroll in prefect lock-step then this isn't a trivial problem. UITableView is a subclass of UIScrollview, so you could probably create a custom subclass of UITableView that overrode various UIScrollView methods and when something caused the table view to scroll, it would do the same thing to the other table view.
Edit: #Schemetrical's suggestion of using the scroll view delegate is cleaner than creating subclasses. You might have to monitor quite a few of the scroll view delegate methods and use them to match the behavior in the other scroll view.
EDIT #2:
Apparently I'm wrong and scrollViewDidScroll is called for every change in the scroll view, so it's simpler than I thought to keep them synced. I'm going to leave my answer for context even though I was wrong.
I've got a UITableView with one section and enough rows that the tableView needs to be scrolled to get to the bottom. I want to add a footer view which will stick to the bottom of the tableView and always be visible, so I have implemented viewForFooterInSection. Here's my code:
- (UIView*)tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section {
NSLog(#"Get footer view");
if (tableView == [self tableView]) {
return [self footerRowRightView];
}
else if (tableView == [self fixedColumnTableView]) {
return [self footerRowLeftView];
}
return nil;
}
The problem I am having is that the footer view only shows after the tableView has been scrolled, but I want it to be visible from the outset (i.e. always floating whether the user scrolls or not).
As soon as the controller appears and the tableView loads its data, I see "Get footer view" in the log, so I know that viewForFooterInSection is being called straight away. What I can't work out is why it doesn't display immediately, and how to get it to do so.
Thanks in advance for any help!
It is probably your height for the footer not being returned correctly.
Check what you return from heightForFooterInSection
What you need is not a tableview's footer.
Simply add the view corresponding to this header in the superview of your tableview and put it at the bottom of it. Then simply reduce the height of the frame of your tableview to fit the remaining space. And it should do it !
You can no use footer view if you want to stick the footer. Or try with grouped tableview.
Quite a few options by the looks of the other answers. Just to add a hacky workaround I have just come up with, I created duplicates of the views I will be using as footers and added them as subviews of my main view, placed exactly over the position of where the real footer views. The views are retained in properties, so that in scrollviewDidScroll I can do the following:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if ([self preScrollFooterLeftView]) {
[[self preScrollFooterLeftView] removeFromSuperview];
}
if ([self preScrollFooterRightView]) {
[[self preScrollFooterRightView] removeFromSuperview];
}
}
This way the footer appears to be displayed immediately. The fake footer is removed as soon as the user scrolls the tableView, revealing the real footer beneath it. If the tableView is scrolled below the last row, the real header sticks to the bottom of the section and bounces back to the bottom of the tableView when the user lets go.
I added a view "Header View" inside a table view (see structure in screenshot). It has fixed height. I tried to change view's frame size, view is getting smaller, but there is still empty space between header and tableview cells.
I need to change header height dynamically in code. Any suggestions?
I suggest you move the Header View out as a subview of View, set a tag to it, then in viewForHeaderInSection, use the tag to get it. Set the proper height in heightForHeaderInSection. When height changes, refresh tableView. The reason for that is Header View is no longer a subview of the table view, it will always stick to the first table view row.
Also with the current design you can make the Header View a cell, then in the viewForHeaderInSection you can reuse the cell, if you have multiple sections this is the way to go.
In your tableview's delegate, you have to use
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return /*desired height*/;
}
EDIT
According to your comment, if you don't want to change your interface, what you can do is to set a height constraint to that view.
You then make a reference of the constraint to the header of the controller managing the view.
In the code, you can then change the height by changing the value of the constraint and updating the view :
[UIView animateWithDuration:/*animation time in seconds*/ animations:^{
yourHeightConstraint.constant = /*desired height*/;
[self.view layoutIfNeeded];
}];
[self.view updateConstraints];
I'm racking my head over this one, I know this has to be possible but after going over every bit of documentation I still can't come up with something that works well.
Basically, I have a UICollectionView in the LAST cell of a UITableView. What I want to happen is, only when the UITableView is totally scrolled to the bottom, can the UICollectionView in it's last cell start scrolling. And, if the TableView offset reaches the bottom of the CollectionView's tableviewcell during a drag / pan, any additional dragging of the current table view drag / pan should effect the collection view instead of the table view.
Also, when the collection view is scrolling, if a user starts scrolling on the collection view, if the collection view reaches the top of it's scroll (Content Y offset of 0 or less), and additional scrolling of the current pan/drag gesture in affect should cause the containing table view to scroll up.
The reason I want to achieve this effect, is because the table view cell above the last cell containing the collection view, contains a UISegmentControl that toggles the contents of the UICollectionView, and I want the user to be able to toggle this segment at any time while scrolling in the CollectionView. Meaning the collection view has to scroll but the parent table view needs to not scroll..
I've tried playing with the gesture recognizers, and doing something with
– gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:
This gets me halfway there, I can use a flag to return yes/no to this method if the collection view is to scroll into a negative offset (Past it's top offset) or if the table view has reached the end of it's total scroll.. I get sort of close to what I want to achieve, but if I scroll up slowly on the collection view, it doesn't fire the simultaneous recognizer, same happens if I scroll down on the table view too slowly.
Another issue is, I do NOT want the collection view to bounce. However setting bounces to NO totally prevents the simultaneous recognizer to fire at all. I even tried setting content offset to CGPointZero on the collection view in it's viewDidScroll if it's y offset were to dip below zero. This also doesn't work and prevents the simultaneous method from firing...
Does anyone have any idea what to do? Or something to point me in the right direction?
UPDATE -
Still trying at this, I've made little progress towards the behavior I'm trying to achieve. I've messed with toggling userInteractionEnabled in the viewDidScroll method, as have I tried in willBeginDragging. The same with scrollEnabled property.. No luck :( I get a behavior similar to what I want with this, however the parent view will not scroll up until the user lets off the screen and attempts to scroll again..
UPDATE -
Is there anyway to transition the panGestureRecognizer currently handling scroll events DURING scrolling? If I could transition the scroll handler from the child to the parent while still scrolling this would solve my issue. I've looked through apple's gesture related and uiscrollview related documentation and can't find anything close to doing that.
UPDATE -
Just got done trying something like this..
- (CGPoint)maxParentContentOffset
{
return CGPointMake(0, self.parentScrollView.contentSize.height - self.frame.size.height - 44);
}
- (void)parentScrollViewDidScroll:(UIScrollView *)parentScrollView
{
if (self.contentOffset.y > 0) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y < 0) {
scrollView.contentOffset = CGPointZero;
}
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
CGPoint translation = [scrollView.panGestureRecognizer velocityInView:scrollView.superview];
if (translation.y < 0) {
[UIView animateWithDuration:0.5f animations:^(void) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}];
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
However there is a problem... for some reason I keep getting a bad access error on the following method
- (void)parentScrollViewDidScroll:(UIScrollView *)parentScrollView
{
if (self.contentOffset.y > 0) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}
}
Specifically setting the content offset. Which is really strange, because with breakpoints I'm seeing parentScrollView and self as being set. I'm wondering if it's not a bad access but it's getting trapped in an infinite loop for some reason? Any ideas?
Even though you may manage to make it work now, embedding a collection view inside a table view (both UIScrollView subclasses) is not a good idea and it will bug as soon as apple modifies their implementation.
Try to migrate to a single UICollectionView layout. After all there's nothing you can't achieve with a collection view that a table view can.
Separate your "table view" and "collection view" in two (or more) collection view sections, then implement layoutAttributesForItemAtIndexPath: differently according to the indexPath.section.
To make it table view-like you'll want to return frames whose width are the same as the collection view.
If your layout is simpler then you could use a UICollectionViewFlowLayout (maybe your already are) and implement collectionView:layout:sizeForItemAtIndexPath: as described above.
Figured this out after a good 8 hours.. I had a confliction due to infinite setting of the parent scroll view offset, since I had multiple objects that were of the same class that received a call whenever their parent view scrolled, both trying to set the same parent view offset to zero, which caused the other class to see scroll changing, and calling their method to change offset, and the process happening infinitely causing a crash.
This code however, solved everything and functions exactly as I was desiring. Hopefully this helps anyone else in the future looking to get congruent scrolling between a parent and child scroll view.
- (CGPoint)maxParentContentOffset
{
return CGPointMake(0, self.parentScrollView.contentSize.height - self.frame.size.height - 44);
}
- (void)parentScrollViewDidScroll:(UIScrollView *)parentScrollView
{
if (self.contentOffset.y > 0 && self.isDragging) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.y < 0) {
scrollView.contentOffset = CGPointZero;
}
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
CGPoint translation = [scrollView.panGestureRecognizer velocityInView:scrollView.superview];
if (translation.y < 0) {
[UIView animateWithDuration:0.5f animations:^(void) {
self.parentScrollView.contentOffset = [self maxParentContentOffset];
}];
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
In an application that I've worked, we needed something close to that, we wanted to have a uitableview inside the first cell of another uitableview, which should be scrollable (you can check the app here)
Our approach was quite different, and we thought about doing it your way, but that way was a bit overkill for the time we had, and needed too much custom control instead of using what apple already gives us.
I'll share our method just for you to have another way to solve your problem, since I can't figure out what is wrong in that method call.
On the outer tableview's datasource lifecycle, we were able to know how our inner table view would be, allowing us to feed our inner table view with all the data, which would then gave us the total content size of the inner table view.
With this info, and since we knew (and in your case, you know) the actual cell where the inner table view would be placed, we make that cell's height equal to the height of the inner tableview content size. With this, the inner table view is 'totally visible'(in your case, the collection view) inside the outer table view cell, but since the cell is so big, it looks like we are scrolling the inner table view when we are simply scrolling a really big, special, cell.
And it won't bounce, if you don't want it too.
In our case, this worked, and the implementation was pretty straight forward.
In your case, and since you have a UISegmentedController, you should do a beginUpdates endUpdates and a 'reloadData', upon press in the UISegmenedController, in your outer table view in order to be able to recalculate the collection view's content size and resize the last cell, but that is pretty straight forward.
I know I'm not answering your question, but this method allowed us to achieve something so similar in such a fast and straight forward way that I thought it was worth sharing.
Hope it helps.
I have a UITableView in the grouped style, and only one section. However there is some blank space above and below the table view that is shown when the user scrolls too far. How can I remove this blank space?
You can do this by altering the contentInset property that the table view inherits from UIScrollView.
self.tableView.contentInset = UIEdgeInsetsMake(-20, 0, -20, 0);
This will make the top and bottom touch the edge.
Add this code:
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return 0;
}
- (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section
{
return 0;
}
Actually this question answered my question.
Reducing the space between sections of the UITableView.
UIView can be inserted at the top and bottom of the table(drag and drop). Set their properties as transparent and height of 1 px. This is to remove the extra padding in front of the cells.
you can also use this code for removing space between first cell of uitableview..
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return 0.002f;// set this...
}
Uncheck Extend Edges Under Top bar.
This answer comes quite late, but I hope it helps someone.
The space is there because of the UITableView's tableHeaderView property. When the the tableHeaderView property is nil Apple defaults a view. So the way around this is to create an empty view with a height greater than 0. Setting this overrides the default view thereby removing the unwanted space.
This can be done in a Storyboard by dragging a view to the top of a tableView and then setting the height of the view to a value of 1 or greater.
Or it can be done programmatically with the following code:
Objective-C:
CGRect frame = CGRectZero;
frame.size.height = CGFLOAT_MIN;
[self.tableView setTableHeaderView:[[UIView alloc] initWithFrame:frame]];
Swift:
var frame = CGRect.zero
frame.size.height = .leastNormalMagnitude
tableView.tableHeaderView = UIView(frame: frame)
Comments
As others have noted you can use this same solution for footers.
Sources and Acknowledgements
See the Documentation for more details on the tableHeaderView property.
Thanks to #liushuaikobe for verifying using the least positive normal number works.
My original answer: https://stackoverflow.com/a/22185534/2789144
In my case issue was with the constraints i was applying. I have to change them in order to show 2 rows in my case while bottom of table touching last row.
Use the bounces property of UIScrollView:
[yourTableView setBounces:NO];
This will remove what seems to be an extra padding at the top and bottom of your UITableView.
Actually, it will just disable the tableview's scrollview to scroll past the edge of the content.