I have an NSCollectionView with a vertical NSCollectionViewFlowLayout. I display rectangular icons in it.
I also have a slider in the UI, and when that changes, I adjust the minItemSize, which I then use in collectionView:itemForRepresentedObjectAtIndexPath: to create an equally sized NSImageView to the returned NSCollectionViewItem's imageView. Then I reload the view by invoking reloadData.
After that, the view shows the icons in the new size as intended.
The problem is, provided I have more data to show than fits into the current scoll view, that when the General System Preferences are set to Show scroll bars: When scrolling, the scrollbar disappears after reloading the collection view, and trying to scroll with the trackpad leads to a bounce that's telling me that the scroll view thinks that the content is just what's visible, nothing more to scroll.
But as soon as I resize the window, which also resizes the collection view inside, the scrollbars come back.
Curiously, if the System Prefs are set to Show scroll bars: Always, then the issue does not appear and the scrolling always works, and the scrollbars always remain visible.
I've tried a lot of things to trigger the re-calculation of the scroll view, such as invalidating the layout of the collection view's layout, the scroll view itself, its content view, and also tried to set their needsLayout to true. Nothing makes this work.
Update: The potential duplicate (NSCollectionView does not scroll items past initial visible rect), neither the collectionView.setFrameSize: nor the window.setFrame: suggestions work for my case (I tried adding these line before and after reloadData).
Even if I force a resize of the window like this, it doesn't bring the scrollbars back, only a manual dragging of the window edges does:
[self.collectionView.window setFrame:NSInsetRect(self.view.window.frame, 1, 1) display:YES];
Also note that in my case, initially the scrolling works, just not after resizing and reloading.
Another finding: When I call selectItemsAtIndexPaths:scrollPosition: after reloadData, then the scrollbar comes back. But only if I pass a non-empty NSSet for the paths. And since I may not have selected any items, this isn't a permanent solution.
If no other ideas come up, I'll try to make a demo project.
I've solved it:
I had to delay the call to reloadData, e.g. by calling it from within the block code of dispatch_async(dispatch_get_main_queue(), ^{ ... });
Before the fix, I did call reloadData right from the setSliderValue: handler, which is bound to the slider's value. It appears that this didn't go well together.
Related
I making an ipad application with screen split in half. Each side contains a container and each container holds UIView.
In the left uiView i have a uiScrollView with multiple elements (customs uiview) inside, like a grid but with scroll, and each element support tap gesture.
When i tap each element they work fine and behave like they are suppose to. lets say they do a NSLog(#"tapped!").
Problem comes when i resize either the entire view that holds the scroll view or the Container like so:
navigationVC.view.frame = CGRectMake(0,0, 338,768);
The tap stops working! But if i resize back to its original frame, tap starts working again.
navigationVC.view.frame = CGRectMake(0,0, originalWidth ,768);
I thought the problem would be the elements re-arrange when i resize the scroll view, but in fact its not.
The frame is being resized when i swipe the entire application either left or right.
EDIT:
Behaviour diagram: http://i.imgur.com/4vKpHLQ.png?1
EDIT2: didnt figure it out yet, but i see now that element bound's are changing when the frame is resized.
Got it!
Problem was that when i resized the scrollView the elements.Bounds where changing too. Then i went digging why... could only be something like a anchor... i then started to change a few properties on my XIB.
Under "Simulated Metrics", changed the "Size" drop-down from "Freeform" (add 150, 45) to "Inferred".
Forced the size on initWithCoder, compiled, and it worked.
Thanks Burhanuddin Sunelwala for trying to debug this with me.
I am trying to initiate a scroll view in my UITextView and even though I seem to have selected the appropriate boxes, I can't seem to get the scrolling working. I have gone through multiple questions similar to this but none seem to have the answer.
I included an image of Xcode below:
Question 2: When I scroll down the majority of my text shows but the scrolling stops with two sentences or so left and I have to scroll down and hold it there to read. Any way I can fix this so it scrolls all the way to the bottom of the text?
Can you check the two boxes: Bounce Horizontally and Bounce Vertically and see what's happening? Sometimes your content are actually way bigger than your view, and they are touching a invisible outer box. If you can see they actually move, that means there is nothing wrong with touch or scroll, is just the view layout problem.
For the content issue, my guess is that the content size is not right, you can programmatically adjust it with textView.frame property, set it to a proper size, such as the frame of the window or the frame of the content, which are CGRect classes. Comment below to see if this can solve your second problem.
The text view will not scroll in storyboard, only the app. And the text view will scroll once the content in the text view exceeds the frame size.
If you're using iOS 7+, you can just turn on auto layout, pin each of the sides of the text view to the edge of its parent view, and it works fine without needing to do anything in code.
I have a NSButton sibling on top of a NSImageView.
Whenever I click the window, there are some rendering issues. It looks like this:
As you can see, the white edges are the problem.
Strangely, this problem even persists if I override drawRect:.
Nothing gets rendered at all, but whenever I click it, those white edges appear.
Also, when the background-image changes, the button gets redrawn and the edges disappear.
Any idea what might cause this?
EDIT
I found out that this actually happens with every single instance of NSView
and it actually clears part of the buffer (you can see the desktop wallpaper):
EDIT 2
I also just found out that this does not happen if I layer-back the windows content-view.
Well, this question was impossible for anyone to answer.
My window had a custom contentView, which was just drawing a view with rounded corners.
Instead of using self.bounds, I used dirtyRect to draw the background.
So when the contentView wanted to redraw the background of the controls that were updated, those rounded corners were cut out.
I have a view controller that consists of two child UIContainerViews, one of which is fixed-width, and the other which dynamically adjusts its width based on portrait vs landscape mode. Both contain UITableViews.
For some reason, if the screen loads in portrait orientation it renders fine. However if it loads in landscape and then rotates to portrait, the second (dynamic) table gets all screwy and thinks it's wider than it is/should be, letting you scroll it horizontally which it should not be doing.
The cells of the tableView all size properly and stick to the left side of this "too wide" tableView. However, if I color the background of the tableview pink, I can see the whole thing is extending into this too wide zone.
It's baffling me what's going on here. Shouldn't autolayout be the same regardless of which orientation the view controller was loaded as?
If I log the widths in a viewDidRotate... handler, everything appears to have the correct width, yet it's still rendering in this bizarre way.
Is there perhaps I way I can just force the container view to re-lay it self out?
Update: It is the contentSize of the tableView that is getting messed up. All the other widths are correct when logged, but the contentSize.width is way off. The good news is I can just manually set this back to what it should be and everything works great! However it doesn't answer the question as to why it's happening in the first place or what I'm doing wrong (if anything).
Here's a screenshot:
In order to force a UITableView to (re)calculate its content size, you may use layoutIfNeeded method. It traverses through the view hierarchy and lays out the subviews immediately, so content size is set properly.
Instead of setting the size manually, call this method for your table view.
I'v encountered strange bug, and have no idea why this happens.
I have UIScrollView, in it I have 12 views. Most of them contain UISwitch button and a label. Size of views are dynamic (depending on the lenght of label.text). Everything works and shows, except two views on the bottom. They do get shown, initialize as expected. Yet UISwitches in them do not work, clicking or touching them does not do anything. Both of them are no exception to others (all of them are copy paste). I have double checked IBOutlets, they are fine. I have suspicion something is wrong with scrollView. Maybe beyond some point it doesn't recieve inputs anymore? Eventhough I can scroll up and down and everything is shown just as expected.
Any ideas what to check ?
I have switched these two views with first ones. And more bottom views get unresponsive, like there is a line, beyond which ui is not responsive. Ideas?
You say the switch is in a view (one of 12) and that view is on the scroll view,
maybe the UISwitch is out of the view bounds? Try to set that views .clipsToBounds = YES;, can you still see the switch? If no, it means the switch is out of bounds therefor you gat no touch events. Make that view larger to fix that.
Check correctly. if the UISwitch and UIscrollview user interaction are enabled.
Check whether the UISwitch is added within the UIscrollview's frame.