I have two Scenes in my Storyboard that are nearly identical. Both are UITableViewControllers. Both have header and footer views. The header views have a UISearchBar and the footer views have a UIView that contains a UITextField. Each have only one prototype cell. One is prototyped as a "Basic" cell and the other is prototyped as "Right Detail" cell.
Here's the problem. When I click the UITextField in the footer view on the first scene, the table resizes automatically so that the bottom of the table is at the top of the keyboard. This allows me to scroll the table up so the footer view shows and the user is able to see what they're typing. The other scene will not automatically resize the UITableView so the UITableView cannot scroll the footer view to where it can be seen and the UITextField is hidden under the keyboard. I can't even manually scroll the table far enough since the footer is always at the bottom of the UITableView.
A little added info. The scene that works has many rows of data while the one that doesn't work only has a couple. I tried adding a number of rows until the table had enough to enable scrolling and it doesn't fix the problem.
I have checked everything I can think of and I can't see anything that would allow one of the views to let the UITableView to automatically resize to work with the keyboard and the other not. I must have overlooked something but I can't seem to find it.
Any help will be greatly appreciated!
Rob
I thought this problem was caused by copy-and-pasting from one view to another, but I had the same problem once I'd (in theory) fixed it.
The answer for me turned out to be simple: I hadn't called [super viewWillAppear:animated] in my UITableViewController subclass' viewWillAppear: implementation. Make sure you've got a call to the superclass' method and hopefully the problem will go away.
I am guessing the frame of the tableview is not being resized to the smaller size in the second case.
Print out the frame and content sizes in both the cases once its loaded, that should help you see if there is an issue.
Related
I need to have iOS app with screen like this:
screen
The idea is when user start to scroll down the first UIView to move up until the second UIView reach the top where it will stick and only UICollectionView will continue to move up.
Currently I'm using this structure
UIScrollView (main scroll)
UIView (some banners)
UIView (UISegmentedControl)
UICollectionView (grid with items, scroll is disabled, main scroll is used)
I manage to do it, but I needed to set UICollectionView height constraint manually in the code (calculated based on all items in grid) in order to appear in UIScrollView (everything else is handled by AutoLayout in Storyboard). The problem with this is that UICollectionView think all cells are visible and load them, so the whole recycling & reusing thing does not work. It's even worst because I use willDisplayCell method on UICollectionView to load more data when last cell is displayed, but now it load all pages at once.
My question (actually they are 2)
How can I fix the issue above?
What is the right way to achieve this functionality? Maybe my whole approach is conceptually wrong?
Collection view is a scroll view itself. So maybe you could have same functionality only with Collection view with sections or even custom layout?
I want to add a subview to a UICollectionView in order to make a left panel that scrolls with the collectionview.
Using
[self.collectionView addSubview:myView]
all touches become disabled and I can no longer scroll the view. I've read that adding a subview to a collectionView like this is bad practice.. is this true? Why does it disable touches from reaching the collectionView event when
userInteractionEnabled = NO
I'm trying to do this: imgur link by grabbing the frame position of the first cell in each section, and adding a dot with to myView with the same y value.
Thanks for any help!
Adding subviews using the addSubview: method to a UICollectionView is very bad practice. It can cause a lot of different problems in the normal behaviour of the CollectionView. It can obstruct the views underneath it, capture the touch events, preventing them from reaching the actual scrollView inside the CollectionView, etc. The subviews added using this method will also not scroll as the other elements in the CollectionView do.
The correct way to do what you want is to implement a new type of UICollectionViewCell for the dots, and compute their locations in the prepareForLayout and layoutAttributesForElementsInRect: methods. Basically you'll have either one or two cells in each row. Which ones will have two rows will be determined by you in the methods I've mentioned.
In fact, Apple's docs have a perfect example that's even more complex than what you're trying you achieve. You should check it out from this link.
May I know the purpose of that scroll view ? Because, if you're looking for a subview that displays only a label or image etc., You can use custom collectionview cell instead if I am not wrong... Hope it helps :) :)
I have a tableview which will not budge when touched. It is very confusing to me. It is the most recently added subview (I checked - it is the last entry in my view's subviews array) and for some reason it just won't scroll up or down. If I tap multiple fingers wildly on the tableview it will one in a while highlight the cell under one of my fingers, but it will not scroll even a little. I have set the number of rows to 100 (many more than are visible on screen) and I have set the 'bounces', 'scrollEnabled', and 'userInteractionEnabled' properties to YES.
I know that I have not provided much to go on here, but if anyone could at least give some tips on how to go about debugging this I would be very grateful. Can I log from within the tableView gestureRecognizer handling method? Can I test where my touches are going?
Please help!
Thanks.
A TableView is basically a specialized ScrollView. If it's not scrolling, it seems to me it could be one of two things. Either something is on top of the TableView and is capturing the gesture events before the TableView can get them, or You have set the bounds and contentSize incorrectly. For a TableView or ScrollView, the bounds of the view should be the visible area, and the contentSize (should be handled by the TableView without you needing to do anything) is the size of all the cells in the Table.
So I would check the bounds of the table view and make sure you are setting that to the contentSize, since that would cause it nor to scroll.
Just to make sure it's on the top, try calling
[view bringSubviewToFront:tableView];
In my case tableview "User Interaction" was disabled. I just enabled it & works.
In my case, tableView "canCancelContentTouches" was not enabled. I set it to true in the storyboard.
Can you check the frame of the parent on which the tableview is added? Make sure the parent view have correct frame to include the table view. I have faced this issue sometime back my table view was not responding to touches and there was some problem with frame size. Also do check the bounds and frames of your tableview
-anoop
Please check tableview scroll is enabled.
I just hate XIB and Storyboard. After 30 mins of debugging it come to know that scroll was not enable in XIB.
Thanks
Basically, Table view is just a kind of scrollview. So in case it is not scrolling You should be sure that if the frame size of your table view is less than the contentSize of your table view. For this just log the frame and content size of tableView's scroll view. If you found that frame size is greater or equal to your content size, just correct your layout constrain of your view. And I hope it will work.
My UITableView has a bunch of reusable cells, and when I tap on one of them, it takes me to another view controller (via push segue) showing the details of that cell (let's say it's an item, so it would show details about an item - name, price, image, etc...). When I pop that view controller (by tapping on the back button), the UITableView has a strange behavior:
a) if it's scrolled all the way to the bottom, it will scroll automatically tad up (around 50 points), leaving the last cell barely visible, so I have to scroll back down again. My cell all have 60 points for height.
b) the scrollbar always shows and then disappears, indicating that something is moving that UITableView (although if not scrolled to the bottom, the content will not move automatically).
This happens in multiple UITableView's I have in my app. I am not forcing a reload of the table view in viewWillAppear, so I don't understand what is happening. My content is static after loading from the server (unless the user changes it, and then the reload is executed). But simply showing details of an item and popping that VC doesn't change anything in the table view.
Edit: Okay, I've figured what the problem is: I'm hiding a UIToolbar when pushing that segue. If I keep it always visible (which I don't want), it still shows the scrollbars animating when popping in my table view but doesn't scroll the table view if on the last few rows.
Add the following to viewDidLoad.
self.automaticallyAdjustsScrollViewInsets = NO;
This solved my problem of table view moving down after navigating back to view controller.
I managed to fix the first issue. It seems like the tableview is not taking into account the 44 points of the UIToolbar.
Save the tableview offset in prepareForSegue: (save it in a CGPoint property)
self.tableViewScrollOffset = self.tableView.contentOffset;
Then, in viewWillAppear:, check if it has been modified. If so, restore it.
if(self.tableView.contentOffset.y != self.tableViewScrollOffset.y) {
[self.tableView setContentOffset:self.tableViewScrollOffset];
self.tableViewScrollOffset = CGPointZero;
}
This behavior is indeed a bug in iOS 8.x.
All answers given so far can not really solve the issue. The issue is, that iOS forgets (or doesn't) consider the previously calculated cell sizes, when a table is being redrawn for instance when the view is being pushed.
One approach to solve this can be found here: UITableView layout messing up on push segue and return. (iOS 8, Xcode beta 5, Swift) (so this question is even a duplicate to this one).
However, the solution provided there is overkill and there are certain situations why this caching will fail (for instance a UIContentSizeCategoryDidChangeNotification is not regarded)
But there is a quite simpler solution even though it is odd:
If you are using a manual performSequeWithIdentifier in didSelectRowAtIndexPath, just add a [self.tableView reloadData] just before.
If you are using a IB seque from the cell, just add [self.tableView reloadData] in your prepareForSeque code.
The reason, why this solves the issue is, that this will force iOS to re-estimate the visible cells and so it no longer scrolls the content to another location. Fortunately, tableView reloadData doesn't cost too much overhead here as only the visible cells will be re-estimated.
Just a hunch, have you got a rogue scrollToRowAtIndexPath:atScrollPosition:animated hanging around?
I was also facing this issue. I managed to find it out. The reason in my case is tableview header height was calculating based text and text height was negative due to which tableview was shifting down even though the contentinset and scrollinset are zero.
This was only occurring for first time. Next time it is calculating correct. One weired thing i found is that when Class A (having tableview) have pushed another Class B from init. When keyboard from Class B is opened viewDidLoad of Class A is called. and before Class B is unloaded from navigation controller. Tableview is reloaded for Class A.
Setting the automaticallyAdjustsScrollViewInsets as suggested above did not work neither did caching and setting the tableViewScrollOffset work.
Hence came up with an workaround which worked like a charm for me.
The workaround was to add an Dummy UIView which has height of 1px and width of 320px and place it between the "Top Layout Guide" and the UITableView. This view's background could be set to clear so that it is invisible.
Now using Autolayouts, fix the Dummy View's top to the Top. Now set the tableview's top constraint with respect to Dummy View. Found that this resolved the issue of the tableview's misplacement.
Screenshot of the Dummy View along with the autolayout constraints have been provided for easy reference. The Dummy View has been set to a larger height and red background colour for illustration purpose only.
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