CODEWITHSUNDEEP
cocoanstableview
Giles
Giles

Reputation: 1667

How to scrollRowToVisible without animations

On a Mac, Mail and Finder have a solid looking scroll on their table views when the up or down arrow is held. The row highlight sits flush with the top or bottom of the column and the rows step through with no animation.

8 years ago it seems that it was hard to not do this. Now I can't seem to stop scrollRowToVisible on an NSOutlineView animating.

I have tried wrapping the call with NSAnimationContext.beginGrouping() or CATransaction.begin() etc to set any animation duration to 0.0 but no luck.

Is there anyway to make this call snap - or should I be using something a little lower level?

EDIT

Here is my code. The duration has no effect here. There are always a few frames of scroll animation, and the endpoint of the animation is slightly irregular (i.e. the bottom edge of the scrolled to view is not always aligned with the bottom edge).

if selectedRows != outlineView.selectedRowIndexes {
            outlineView.selectRowIndexes(selectedRows, byExtendingSelection: false)

            // I would love this not to animate like in mail, but it cannot be stopped!!!
            if selectedRows.one {
                NSAnimationContext.beginGrouping()
                NSAnimationContext.current.allowsImplicitAnimation = false
                NSAnimationContext.current.duration = 0
                outlineView.scrollRowToVisible(selectedRows.first!)
                NSAnimationContext.endGrouping()
            }
        }

Using runAnimationGroup has the same result:

NSAnimationContext.runAnimationGroup( { current in
                    current.allowsImplicitAnimation = false
                    current.duration = 0
                    outlineView.scrollRowToVisible(selectedRows.first!)
                }, completionHandler: nil)

I have variable height rows in my table but I don't see why this would make a difference. From the above code, the change in selection is always highlighted before any movement in the table, further indication that the scroll animation is not being removed.

Upvotes: 1

Views: 313

Answers (1)

nangtrongvuon
nangtrongvuon

Reputation: 36

I had this problem myself, and solved it by subclassing NSClipView and overriding func scroll(to newOrigin: NSPoint) like this: 

override func scroll(to newOrigin: NSPoint) {
    super.setBoundsOrigin(newOrigin)
}

This should disable smooth scroll entirely, which is the animation effect you are describing, for the scroll view that houses your subclassed clip view.

Upvotes: 2

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