Good Morning,
I have a PDFView in an NSSplitView. I've implemented zooming and scrolling, using trackpad gestures. However whenever I reload the PDF, the scroll position resets to the top left corner. This is ok if the full page is shown, but if the PDF is zoomed and only partly visible, this can move the section of interest out of the view.
I've tried using enclosingScrollView but that returns nil. I've tried digging through the subviews to find the NSScrollView, the NSScrollers, NSClipView many of the displayRect and related properties are readonly. I've tried reading the verticalPageScroll and verticalLineScroll but they only every return 10.0.
I seem to be left with systematically going through the class properties and methods of each subview and see if they contain the data.
I'm sure someone knows how to get and set this.
Thanks.
Mark
Related
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.
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 problem in playing with the UIScrollView i am using a customImage Object class to display images on scroll view and event fire on each image i achived it all but i have to do a extra work on it as the giving image showing that the middle image is pop out and fire event for that popout image...
i am confuse in it can anyone tell me how to achive this ....
please told me some steps to start with it..
You should be implementing the UIScrollViewDelegate protocol in the controller which should be handling the UIScrollView.
In there you will get a plethora of delegate callbacks such as when the scrollView moves or is decelerating towards a complete stop etc.
"UIScrollViewDelegate iOS reference"
You can implement any of the methods to suit your exact needs and modify the image's properties. To find which image is in the middle you would be comparing the contentOffset property of the scroll view o image locations.
Couldn't find anything on the net about this and wondered if anyone on SO has a solution.
I have an NSView with several subviews that are centered by removing the left and right anchor points. When I resize my view, programatically or with the mouse, to a smaller width than the subviews: it pushes them off center. Has anyone come across this before and do you have a solution?
EDIT: I want to be able to resize my view to a zero width. The reason being, the view is actually part of a split view and I have hooked up a button to 'collapse' it. When it collapses all of the subviews are pushed off-center and aren't re-centered when the view is resized, effectively un-collapsing it.
I have solved my problem now and thought I would share incase anyone comes across this issue in the future.
No amount of playing with autosizing options or view layouts in Interface Builder seemed to stop my subviews from getting moved off center. I did manage to find this link here and from this page, the advice:
Springs and struts, as currently
implemented, are really no good for
anything but keeping either one or
both sides of a view "stuck" to the
nearest edge. Any sort of centering
behavior, division of gained/lost area
between multiple views, etc. has to be
done by hand.
Based on this I overrode my view's setFrame: method and manually laid out my subviews using their setFrame: method. This works great and gives me the results I'm looking for.
There is the same issue using NSSplitView, resizing here one Subview to be smaller than the Subview Subviews makes sense,e.g. having small charts in the upper subview, and an rss reader in the lower subview.
If you want to show only the rss reader in the lower subview, you can "hide" the upper subview, but after resizing the upper subview the NSImageView are not layed out the same as in the beginning. Check this nib/xCode Project and the following screenshot to see this behaviour.
Only workaroung is to override the resize function to stop getting smaller.
I have an NSScrollView with an IKImageView inside to display images. This seems to work.
However, if I make the window smaller than the image, the scrollbars appear as they should, but the BOTTOM of the image is locked to the bottom of the window, instead of the top of the image being locked to the top of the window. In other words, I want the image to not move on the screen when I re-size the window from the bottom right.
I understand why this is, because in All of these classes, the origin is in the lower left, not the upper left. However, It's still behaving wrong. If you look at any other product (including Preview, which I assume is written with some of these libraries) the image/content/whatever, is locked to the top not the bottom.
How do I do this?
I've looked for methods in the NSScrollView and IKImageView. I've considered capturing the scroller events and manually moving the image down or up as appropriate, but I haven't seen a way to do this (Set the selector to a method I write in the controller?) and anyway, that seems very messy...
Is there an easy way to do this?
thanks.
Solution for future reference:
Make a subclass of IKImageView with only one over-ridden method:
-isFlipped()
{
return YES;
}
This subclass will also prove useful if I find that I need to re-implement the rotate:(id) method and the setImage:(NSImage) method which exist in the class (and in the case of rotate are USED IN THE DEMO supplied by Apple) but not documented, and therefore not officially supported...