问题
I'm attempting to reproduce the iTunes 11 behavior of navigable views within a popover. I can't seem to find a way to get my animation to happen at the same time as the popover's contentSize
change happens, though.
The basic setup I have is a custom view subclass MyPopoverNavigationView with two subviews: the old and new views that I want the popover to navigate between. The popover's contentViewController
has a MyPopoverNavigationView instance as its view
. I do this:
// Configure constraints how I want them to show the new popover view
[NSAnimationContext runAnimationGroup:^(NSAnimationContext *ctx) {
[ctx setDuration:0.25];
[ctx setAllowsImplicitAnimation:YES];
[self layoutSubtreeIfNeeded];
} completionHandler:nil];
As far as I can tell from the Auto Layout WWDC 2012 videos, this is the recommended way to animate changes to views' frames as a result of constraint changes. It works, but the animation happens in two phases:
- First, the popover's
contentSize
will change to accommodate the new view that I'm moving to (before that view becomes visible, so it partially obscures the existing content). - Second, the views animate as I expect, so that the constraints system I installed is satisfied.
From setting some breakpoints, it looks like -layoutSubtreeIfNeeded
eventually calls a private method on the popover called _fromConstraintsSetWindowFrame:
, which does the popover size animation outside my animation group. My context's duration isn't respected, and my animations don't happen until the popover's size change is complete.
How can I get my views to animate together with the popover's size change?
回答1:
Turns out the trick is to explicitly set the popover's contentSize
property outside of the animation and completion blocks. The relevant snippet from the sample GitHub project I put together to figure it out looks like:
// Configure constraints for post-navigation view layout
[NSAnimationContext runAnimationGroup:^(NSAnimationContext *ctx) {
[ctx setDuration:0.25];
[ctx setAllowsImplicitAnimation:YES];
[self layoutSubtreeIfNeeded];
} completionHandler:^{
// Tear down some leftover constraints from before the transition
}];
// Explicitly set popover's contentSize so its animation happens simultaneously
containingPopover.contentSize = postTransitionView.frame.size;
回答2:
This works fine for me on Sierra:
let deltaHeight = 8
let contentSize = popover.contentSize
NSAnimationContext.runAnimationGroup({ (context) -> Void in
context.allowsImplicitAnimation = true
popover.contentSize = NSSize(width: contentSize.width, height: contentSize.height+deltaHeight)
})
来源:https://stackoverflow.com/questions/14783711/animating-auto-layout-changes-concurrently-with-nspopover-contentsize-change