UITableView contentOffset changes on drag - ios

I have an UITableView and I want to hide a part of it's header (kind of pull to refresh). I did it with contentOffset and it works fine when the content is larger than the screen. It hides when needed and show when needed but when the content takes up less space than the screen, it changes the contentOffset from (0,50) to (0,25.5) every time I start to scroll. I think it i not related to my code because I commented out everything that had something to do with contentOffset except the viewWillAppear method what sets the contentOffset the first time. Any idea?

On attribute inspector, unchecked Adjust Scroll View Insets as show in image below

Related

Nested UIScrollviews behaving strangely

I have the following autolayout-driven setup:
Main viewController, with a scrollview inside it. Scrollview pinned to superview edges. This one scrolls up and down.
A few normal, fixed size views at the top of the scrollview
Another scrollview. This one scrolls left and right. The second scrollview contains a couple of tableviews, side by side. The idea is that the user can switch between them. They both contain a handful of cells, all the same width as the screen and 72pts tall.
The problem I'm trying to solve is that the tableview contents are not the same size. The left one has say, 6 cells, and the right one has 3.
My first approach was to dynamically change the second scrollview height to match which ever tableview was currently visible. What ended up happening was that switching between the two tableviews (by doing setContentOffset:animated:) went extremely wrong if animated was set to true - it would adjust the content offset so everything was offscreen. In fact it would set the content offset to and then as I switched, about a dozen times, then it'd reset. It was weird, I gave up.
Now I'm trying to just adjust the content inset of the main scrollview to offset the gap in the content of the current tableview, and it's also being weird. When I set the bottom content inset in viewDidLoad, it works fine. When I set it at the time the tableview becomes current, it does nothing.
What gives? What scenarios would lead to these view interactions not behaving properly?
Use different tableViewController for each table.
Embed them in pageViewController.
Add those few normal, fixed size views at the top of the pageViewControllers view.
Conform scrollViewDelegate in pageViewController.
Pass scrollViewDidScroll from tableViews to pageViewController.
Set tableViews inset to match those fixed size views at top.
Change height according to the scroll.
This is the way you can achieve the functionality you want.
I hope it helps.

Have a UITableView extend its footer beyond its height?

I have a UITableView at the bottom of the screen that pulls up and then snaps back down. When it is pulled up, though, you can see the view behind it because the tableview's height is finite and less than the size of the screen.
I tried using a large footer, but that affects the snap-back of scrolling the table up.
I also tried setting a fixed height for heightForFooter and returning a large view from viewForFooterInSection, but that view gets cut off after it reaches the height returned by heightForFooter
How can I display fixed content beneath my table without affecting its scrolling?
Add a background view to your table view, and then add a subview to that view with the color you need. You can position the subview around table/section headers.
In viewDidScroll, update the y position and height of the subview.

TableView height change while scrolling resets contentOffset

I encountered an animation flicker that occurs when dragging down a UITableView. If the height of a UITableView changes during a 'rubber banding' drag, the contentOffset gets set to the contentInset when the table height change animation completes.
Here's a project reproducing the issue, as well as a bad work around. If you drag the table down, you should see the table contents flicker back to the top momentarily.
Anyone have any ideas for a better workaround?
https://github.com/KingOfBrian/AppleBugs/blob/master/ContentOffsetBug/ContentOffsetBug/RZViewController.m

UITableView stops scrolling enough after I add/remove a view to the superview of table view

Here is the problem that I'm facing. I have UITableView inside main view. When user taps menu button, view is added to the view hierarchy of superview, and this view covers all screen, except the menu button. That is I call
[self.view insertSubview:self._menuView belowSubview:self._menuButton]
After user clicks the menu button again I call
[self._menuView removeFromSuperview]
However, after this, the UITableView stops scrolling, actually it scrolls, but just a little, couple of pixels, and then bounces back to the location on which it was before I inserted _menuView. I've monitored the menu hierarchy after inserting and removing the _menuView, it is actually removed, and also there is no view which covers the UITableVIew, so there is no chance that some other view steals touches from UITableView. What can be the problem? Any ideas?
EDIT 1: I've noticed besides not being able to scroll, another strange thing happens. When I show menuView, the tableView is scrolled to top, without animation. (the menuView is half opaque only, so I can see the tableView underneath it)
EDIT 2: I've monitored contentSize and contentOffset of tableView before and after inserting _menuView, the reason for not being able to scroll is that somehow contentSize is being changed.
TABLE VIEW BEFORE INSERTING MENU - contentSize:{Width=320, Height=10519} contentOffset:{X=0, Y=3980}
TABLE VIEW AFTER INSERTING MENU - contentSize:{Width=320, Height=44} contentOffset:{X=0, Y=0}
As You can see, the height is changed to 44 that's why I'm not able to scroll. And Also, as I've said in EDIT 1: tableView is scrolled to top - so as you can see contentOffset is also zeroed. Any ideas why content size changes automatically?
Thanks in advance.
i think there is problem with your tableview frame. right after removing subview, try to set frame of your tableview at its original frame.may this will solve your problem
Content in the UITableView organized automaically and designed only to show cells & header/footer elements. To proper working you should wrap your table into parentView and add your menu to that parentView rather than to the UITableView. You can also try to call reloadData method on table since it can restore the content size of the view.

UITableView Section Headers not visible when table in visible rect

I have a UIScrollView with 3 UITableViews stacked horizontally. I switch between these tableviews using a tab-controller on top. However, when I switch to the 2nd or 3rd tab and switch back quickly to 1st the section headers don't show. They display when I scroll the tableView. These are custom headers (jfyi). I tried calling setNeedsDisplay when the tableView is visible, but that does not help because as per Apple Docs :
If you simply change the geometry of the view, the view is typically not redrawn. Instead, its existing content is adjusted based on the value in the view’s contentMode property. Redisplaying the existing content improves performance by avoiding the need to redraw content that has not changed.
Since, only the geometry of the view is changing here, it does not help. Also this happens on all versions iOS 5~6.1 and on simulator and device. Thankfully, this does not crash the app, but its a problem nevertheless. Could someone help? I am attaching pictures for reference. First shows the problem, second: after scrolling the "head(er)less" tableview
EDIT:
I am using simple scrollRectToVisible:animated: to switch between tableviews. This does the trick but I just observed that when I set ...animated:NO all is okay. The problem happens when ...animated:YES
It seems the issue of displaying and scrolling taking place simultaneously for the respective tableview. So what you can do here is:
Remove the scroll animation
or
Just scroll the tableview to top on the tab press event
or
simply reload the tableView which is made visible

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