I want a cell in UICollectionView can be tapped(not selected,because selected cell would be add to the [cllectionView indexPathsForSelectedItems]), what means: when I tap a cell I can show a detail view of the cell and it would not be add to [cllectionView indexPathsForSelectedItems].
AFAIK, there is no way to do this at this time -- other than to deselect the item after the selection is made. I spent a lot of time trying to make this happen and it just doesn't work.
The problem is this: You have to get hold of the default gesture recognizer for the collectionView tap to require it to fail, and you can't. Apple gives some instructions, but they don't work as advertised. See page 36 of:
http://developer.apple.com/library/ios/documentation/WindowsViews/Conceptual/CollectionViewPGforIOS/CollectionViewPGforIOS.pdf
The problem is that the sample code in this article doesn't work. On inspecting the default gesture recognizers, you'll find there isn't one of the class type UITapGesureRecognizer. It may be you can figure out what's going on with it, but I never could (if you figure it out, I'd sure like to know how to do it).
Ultimately, everyone workaround I tried failed, and I ended up having to settle for using a long press. There are some other posts on this subject, but I never could find anything else that actually worked. This was all on iOS 6.0.
Someone had also asked about using a double tap, and I could not get the select to consistently fail on that. At first I thought that was the solution, but found that it would sporadically select the cell that was double-tapped, and with no other workaround had to move to the long press, which seemed to work. In the end I had to scrap that work for other reasons, so I never put it in production.
Hope you can find a solution but my experience was not good.
Related
I've run into a strange UITableViewController behavior.
For explanation:
I have a quite simple UITableView. Just 3 Default Cells with a Text.
But it behaves like shown in the GIF below. (The GIF is a little bit slower than reality)
Normal "short" taps are neither highlight or select something.
A longer press highlights the cell until released.
And only after a long long tap the cell is selected.
I have no idea what can cause these issue and I don't know where to search.
Some Code: TableViewController + DataSource
Have anyone a hint where to start debugging ?
You've probably set up a tap gesture recognizer somewhere else in the view hierarchy which is eating your tap gestures.
Since you're presenting a plain vanilla table view, you really don't want to do that.
(apologies in advance to the community -- this should've been a comment but I can't comment because I've got a bad reputation)
I've got it ;)
I've found a TapGestureRecognizer within a self written sub framework.
After commenting this out it works well.
So I have to search the issue within my sub framework.
A lot of thanks to you, without your hint I never thought about it again 🙈
When returning from a ViewController where I add and save an NSManagedObject, the TableView inserts a blank cell where the new cell should be. If I back out from the tableview screen and go back, it reloads and configures everything properly.
So what I know from this is that the data is being properly saved to the store, I know the FRC delegate operations are all being called (.Insert, for instance), and I actually can see via breakpoints that my "configureCell" method is being called and is passing back a fully configured cell. The tableview is just putting in a blank one instead.
I can post code if you'd like, but I was just curious if this description rang any bells for anyone? I've been researching this problem off and on for weeks but haven't really found anything similar.
For troubleshooting purposes I:
took my custom UITableViewCell out of the mix and just had the tableview configure a generic cell... didn't help.
created a stripped-down version of the app flow in another project, including core data, FRC, custom tableview cell, etc... this actually DOESN'T display the same behavior. I've compared the two projects side by side and can't determine any meaningful difference (other than the data itself that's being displayed).
I've even gone so far as to insert a delay between the context.save() operation and dismissing the VC where I create the object, just to see if it's some sort of race condition between when the object is created and when the table configures the cell. Needless to say, that did nothing.
Is this a bug anyone else has encountered? Anyone seen this behavior before?
Thanks in advance, sorry for the wall but this is something that Google, various subreddits, and so far StackOverflow has not been able to help me with.
Well after rephrasing my question I found this from back in May.
New table view cell shows as a blank cell
No solution there, but I reached out to him via twitter and his suggestion worked. Switching my size class back to any/any seems to have solved the problem, which means this might be an autolayout bug. It needs more testing but I think I've done everything that would demonstrate the issue and I think it's resolved.
I have an uicollectionview with paging enabled. One cell per page which is full screen basically. The thing is that when I want to use scrollToItemAtIndexPath and move one cell forward/backward along with animation it will do a swipe but it will go back instantly to the cell/page where I called scrollToItemAtIndexPath. There is really nothing special besides stuff I've described. When I omit animation it's working.
For faster debugging I've setup test project on github - ScrollToItem
EDIT: This might be a bug. Bugreport (18864560) submitted. If someone can provide me a workaround or even solve this issue it will be still appreciated.
Have a strange issue where about 15% of the time, when selecting a cell with a UITableView the cell highlight flashes quickly and didSelectRowAtIndexPath is not called. The rest of the time it is working fine.
Tested how it was being selected (fast / slow finger nail, etc), but this does not seem to be the case. Looks semi-random.
Any thoughts one what might be causing this?
IOS 6.x
[Addition]
Thanks for the comments so far.
If while clicking the mouse (simulator) is moving, the problem can be duplicated. Even if the table is set to .scrollEnabled = false it is still happening. Also, the didHighlightRowAtIndexPath does fire and the didSelectRowAtIndexPath does not in the "quick" case.
Same thing happens on IOS 5.x also...
[Conclusion]
Well, it turns out that the scrolling was turned off for the table and it seems to be even more picky with the "moving tap" Turning the scrolling on actually made the "moving tap" less picky. There were a couple of other postings that I just found that pretty much said the same thing. This is a strange conclusion for a table view that has scrolling disabled and produces a "quick highlight" with no selection. Looks like this is why they added the didHighlight in IOS 6 to try and get around this "issue".
is it possible that a view from with in the cell is absorbing the touch rather than the cell ?
maybe you have a gesture recognizer in the cell, those take priorities over simple touch events
It seems that for some reason your cell is disabled. Try setting cell.enabled = TRUE; right before the cell is displayed and see if it fixes anything.
You're moving your finger up or down slightly, causing the table to scroll. Your item will not be selected, and the highlight will disappear. I've dealt with this before by tracking the row in tableView:didHighlightRowAtIndexPath, and then doing the action in tableView:didUnhighlightRowAtIndexPath: . You might also be able to solve your problem by making the tableView not scrollable if that's an option in your ui.
I've noticed a problem when using UIPickerView, and I'm wondering if anyone has ever encountered it before: Sometimes when scrolling one of the wheels, it gets stuck between two rows (after touches have ended), and just stays like that indefinitely. Dragging the wheel again slightly and releasing always corrects the problem, but regardless, I'm puzzled as to why this is happening in the first place. It occurs when testing both in the simulator and on an actual device.
The problem isn't so much the annoyance of having to re-adjust the wheel when it gets stuck, but rather that sometimes it gets stuck when it's extremely close to selecting a row (but hasn't actually selected it) which can give the user the impression that they have chosen a given row, when really they haven't.
Has this happened to anyone else, and if so, is there a way to fix it?
Thanks,
Chris
Still haven't figured out a good way to solve this... the best solution I've been able to think of is including the following line in the pickerView:didSelectRow:inComponent: method:
[pickerView selectRow:[pickerView selectedRowInComponent:0] inComponent:0 animated:YES];
This will make the specified component roll back onto the correct row, ensuring that the user is always seeing an accurate representation of what's selected, however it sometimes looks strange when you think the component is going to stop on a certain row, only to see it animate backwards in the opposite direction before stopping.
I had an issue very similar to this. The UIPickerView would scroll and stop between rows. Normally this view will not stop between rows it will scroll itself to the next row even if you try to stop it in-between two items. I have many apps that did not show the problem even though they used the same code to instantiate UIPickerView.
After much investigation I found my problem was over usage of CPU. My application is an OpenGL game, so I have a game loop running as fast as possible to update the frames. Admittedly my game was CPU bound and not achieving a full frame rate. I was leaving the game running in the background while the pickerView popped up to allow the user to make a selection. This seems to have left no CPU for the UIPickerView to detect it had stopped between rows and pull itself to the nearest row.
My simple solution is to pause the game while the picker view is up.
I see this answer is a year late, but it took me a while to figure out so hope it helps someone.
I think I've figured it out. When the view that you are using the UIPickerView in loads, you need to set the pickers delegate, like this:
picker.delegate = self;
That should fix the issue and cause the picker to automatically center on a value rather than floating between rows.
you should check frames of the subviews in pickerview delegate method (pickerView:viewForRow:forComponent:reusingView:). frames height should should not exceed from content view's height.