I have a basic implementation of NSCollectionViewLayout very similar to NSCollectionViewFlowLayout:
It places item in a horizontal row. If there's not enough room, the next item is added to the next row and so on.
My question: how can I animate a layout change when an item moves from the first row into the second row?
Here's an example:
Note how item #3 "jumps" from the first to the second row. I'd like to animate that change.
There are lots of methods to animate adding/removing items, but I was not able to figure out how to animate layout changes when no items change.
The methods you're looking to override in your layout subclass are prepare(forAnimatedBoundsChange:) and finalizeAnimatedBoundsChange().
From the documentation:
open func prepare(forAnimatedBoundsChange oldBounds: NSRect) // NSCollectionView calls this when its bounds have changed inside an animation block before displaying items in its new bounds
Prepares the layout object for animated changes to the collection view’s bounds or for the insertion or deletion of items.
open func finalizeAnimatedBoundsChange() // also called inside the animation block
Cleans up after any animated changes to the collection view’s bounds or after the insertion or deletion of items.
Related
How can you blur the whole view except a single table view cell?
The effect should be similar to the 3D touch blur effect. E.g. Mail app:
The effect of blur applies precisely to the whole screen but the selected cell in the case of the mail app.
If you only want the effect to apply to your table view, you could maybe put a blur visual view on tope of your each cell's content, and set its effect to nil
cell.blurView.effect = nil
appart when one cell is selected. To do that, play with the didSelectRow function and reload the data so that at the end you get the effect you want. (you can even animate the change with UIView.animate())
UIView.animate(withDuration: 0.5, animations: {
cell.blurView.effect = UIBlurEffect.init(style: .light)
}
The problem is that the solution I told you is not very power efficient, but I can think of another one:
Consider having two blur view that display no effect when no cell is selected, then you can as soon as the cell is selected, set the two blur view so that the first one takes the whole part of the screen at the TOP of your cell, and the other one covers the BOTTOM.
Ok last idea:
you could, in the didSelectRow method, add a blurView to the whole screen
UIApplication.shared.keyWindow?.addSubview(blurView)
and then add the cell on top of that and of course removing all this when the blur view is tapped for example
Hope it helps ;)
AppKit Release Notes for OS X v10.11 suggests that collection view items can be resized on a per-item basis:
Item size can be determined globally for all of a CollectionView’s items (by setting an NSCollectionViewFlowLayout’s “itemSize” property), or can be varied from one item to the next (by implementing -collectionView:layout:sizeForItemAtIndexPath: on your CollectionView’s delegate).
In my case, my CollectionViewItem consists of a single label that contains a string of varying length. I'm using the NSCollectionView to display an array of strings, as NSStackViews don't support array bindings, and don't flow to new lines. The array of strings is bound to the NSCollectionView's content via an array controller.
My item's nib file is properly set up, the root view and the label both have Content Hugging and Content Compression Resistance Priorities of 1000, and the edges are aligned via AutoLayout.
Now, the NSCollectionViewLayout's delegate method has this signature:
func collectionView(collectionView: NSCollectionView,
layout collectionViewLayout: NSCollectionViewLayout,
sizeForItemAtIndexPath indexPath: NSIndexPath) -> NSSize
My idea now is to grab the item itself, run a layout pass over it, and then returning the new item size.
let item = collectionView.itemAtIndexPath(indexPath)!
item.view.layout()
return item.view.bounds.size
Problem with this approach is that itemAtIndexPath returns nil. If I return a default size in the nil case, that default size is used for all cells.
How can I set a NSCollectionView to respect my item's AutoLayout constraints and for each cell, use the computed size dynamically?
There's a duplicate of this question that I answered but this is probably the one it should be directed to since it's older.
Juul's comment is correct- the items do not exist. sizeForItemAt being called is the collection asking the delegate for any specific sizing for that data entry with which it will use to help create its eventual view controller, NSCollectionViewItem. So you create a loop when you ask the collection to get you an item in the method that it uses to help get an item.
The problem we have is that we want sizing based on the appearance of that data: the length of a text label with proper formatting, not just, say, the string length. So we hit a chicken and egg problem.
The only solution I've come to, which could be prettier, is the following:
Prep
Subclass NSCollectionViewItem and ensure your collection view has a data source that returns the proper subclassed item.
Use constraints in your XIB, completely.
Your subclass should have a method that loads in the data object to be represented- both for this and of course your data source protocol methods.
At some point prior to the first sizeForItemAt call, or at the beginning of the first one if you hadn't by then, manually create an instance of your NSCollectionViewItem subclass, and use NSNib's instantiate(withOwner:topLevelObjects:) to instantiate its XIB with your subclass as an owner. Store that reference as a sort of "sizing template," so you only need to do it once. Delegate was easiest spot for me.
^Note: my first route was to attempt this through the collection's makeItemWithIdentifier, but it was more brittle as it required the collection to have items at the time of creating the sizing template. It also could not be done during an initial sizeForItemAt (accessing/making items during a reload crashes). And I was worried that because it was made with the collection it may get reused down the line and the methods below don't work or start editing visible items. YMMV.
In sizeForItemAt
Directly get the data object being represented from the datasource. Have your sizing template object represent that data object with the method I mentioned earlier.
Access the sizing template's View.FittingSize, the smallest size an item can be given its constraints/priorities, and return that.
Bam! Hasn't been stress tested or anything but no problems on my end, and its not doing a layout pass or anything, just calling FittingSize. I haven't seen this articulated anywhere online yet, so I wanted to write out the full explanation.
I did this in Xamarin.Mac, so my code won't be 1:1 and I don't want to write garbled swift and mess anything up.
TLDR: manually instantiate a NSCollectionViewItem subclass and its xib that you will store, unowned by the collection. During sizeForItem populate that item you store as a sizing reference, and return the FittingSize of the collection item's view.
I'am using autolayout with NSSpliView, the setup is as following on the picture
The split view is in a window which can resize, when it resizes, the divider is changing proportional 50:50, how to change this, so that the height of the bottom view stays and the top view gets resized (but no more than 124px) but still have the freedom also to change it manually by dragging the split?
So just to recap you have three requirements,
Bottom view stays the same size on resize
Reduce the holding priority if the top view (select the NSSplitView to get the correct inspector)
Top view cannot resize more than 124px
Add a inequality constraint which sets the height of the view to less than or equal to 124px. You can do this in IB. It will also be a good idea to create a IBOutlet for this constraint in your custom view of controller class for the next step...
When the divider is moved the top view should be able to get smaller than 124px.
I not entirely sure but checkout the NSSplitView delegate method such as splitView:resizeSubviewsWithOldSize: or splitViewDidResizeSubviews:. When you resize with the divider the delegate method should override the height constraint to be the current resized size. So something like the following in the delegate method
self.heightConstant.constant = NSHeight(topView)
Or you could just remove the constraint and re-add it later when needed.
I need to create a view based tableview in Popover as specified below:
Tableview should be placed in Popover(Popover height should be same as tableview).
Each row should contain a view.
Each row view will contain 3 labels.
Labels should be auto re sizable based on its text height.
Based on 3 labels height, Cell row height should resize.
Based on all cell rows, tableview height should resize.
Based on tableview height, Popover should resize.
I have done this in a static format, but i need to do it in more dynamic format(in future i should be able to add more rows using same classes and methods).
Main problem i am facing is, i am unable calculate the size of cell view in tableView:heigthOfRow: since i don't know the text of labels in this point of time.
So i just created tableview cells in loadView itself and saved in array, and fetching from array in tableview delegate methods. But i think this is wrong way of doing so.
Note: All data to tableview will be given while loading the view itself. Labels are not editable.
Cocoa system resizes the subviews based on superview ,I think scenario that you are looking for is to resize super view based on subview size.
Following 2 solutions i can suggest right awyay,
1.You can choose to post notification upon size change in each subview and make immediate superview observe that.
2.Use globals for size of each subview in your case 3 labels, and have an API to calculate finalRect in your view of view based table view.
Hope this helps:) have a nice day.
I have an NSOutlineView which I draw badge numbers to the right side of cells using drawAtPoint:, NSAttributedString, and of course NSBezierPath. My problem exists when resizing of the outline view occurs when within a subview of an NSSplitView. The badges move along with the resize to the left or right. When they get to the text of the cells themselves they do not stop or truncate the text under them. It just flies right over.
Is there a way to have the cell recognize the custom drawn view next to it and truncate text accordingly? I have tried the solution PXSourceList already, but that did not help either.
"PXSourceList solution" working good. You subclass NSOutlineView and overload frameOfCellAtColumn for this particular task. At this function you need to decrease width of cellFrame, returned from super call, by the width of your badge plus padding.