Programmatically toggle resize of NSSplitViewItems - objective-c

Question

I am trying to find a way to programmatically resize NSSplitViewItems.
Say the NSWindow frame size is 500x500px.
masterViewItem has a width of 100px, while subViewItem has a width of 400px.
When FOO, I want masterViewItem to collapse to 0px (towards the left),
while subViewItem expands to fill the entire window (500px).
When BAR, I want masterViewItem to expand back to 100px, while subViewItem collapses back to the original 400px.
- (IBAction) onTapOnSomeButton:(NSButton *)sender {
NSWindow *window = [[NSApplication sharedApplication] mainWindow];
NSSplitViewController *splitViewController = (NSSplitViewController *)[window contentViewController];
NSSplitViewItem *masterViewItem =[splitViewController.splitViewItems firstObject];
NSSplitViewItem *subViewItem = [splitViewController.splitViewItems lastObject];
if (FOO) {
[NSAnimationContext runAnimationGroup:^(NSAnimationContext *context) {
// Expand subViewItem
} completionHandler:^{
}];
} else if (BAR) {
[NSAnimationContext runAnimationGroup:^(NSAnimationContext *context) {
// Expand masterViewItem while shrinking subViewItem
} completionHandler:^{
}];
}
}
I am able to animate each item so that it seems to collapse/expand,
i.e.
subViewItem.viewController.view.animator.frame = CGRectMake(0, 0, window.frame.size.width, subViewItem.viewController.view.frame.size.height);
but the divider will not move, making the two items just move individually, and does not look like the entire screen is collapsing/expanding.
How would I implement this? Thanks in advance.
UPDATE
So I have done a bit more research, and found this:
How to animate the NSSplitView while resizing?
So I made code like this:
- (IBAction) onTapOnSomeButton:(NSButton *)sender {
NSWindow *window = [[NSApplication sharedApplication] mainWindow];
NSSplitViewController *splitViewController = (NSSplitViewController *)[window contentViewController];
NSSplitViewItem *masterViewItem =[splitViewController.splitViewItems firstObject];
NSSplitViewItem *subViewItem = [splitViewController.splitViewItems lastObject];
if (FOO) {
NSMutableDictionary *collapseMainAnimationDict = [NSMutableDictionary dictionaryWithCapacity:2];
[collapseMainAnimationDict setObject: subView forKey:NSViewAnimationTargetKey];
NSRect newRightSubViewFrame = subView.frame;
newRightSubViewFrame.size.width = splitViewController.splitView.frame.size.width;
[collapseMainAnimationDict setObject:[NSValue valueWithRect:newRightSubViewFrame] forKey:NSViewAnimationEndFrameKey];
NSMutableDictionary *collapseInspectorAnimationDict = [NSMutableDictionary dictionaryWithCapacity:2];
[collapseInspectorAnimationDict setObject: masterView forKey:NSViewAnimationTargetKey];
NSRect newLeftSubViewFrame = masterView.frame;
newLeftSubViewFrame.size.width = 0.0f;
newLeftSubViewFrame.origin.x = splitViewController.splitView.frame.size.width;
[collapseInspectorAnimationDict setObject:[NSValue valueWithRect:newLeftSubViewFrame] forKey:NSViewAnimationEndFrameKey];
NSViewAnimation *collapseAnimation = [[NSViewAnimation alloc] initWithViewAnimations:[NSArray arrayWithObjects: collapseMainAnimationDict, collapseInspectorAnimationDict, nil]];
[collapseAnimation setDuration:0.3f];
[collapseAnimation startAnimation];
[splitViewController.splitView adjustSubviews];
[splitViewController.splitView setNeedsDisplay: YES];
} else if (BAR) {
// Not yet implemented
}
}
But to no effect. Any suggestions?

Answer 1

You have to resize the panes using [NSSplitView setPosition:ofDividerAtIndex:].
I have no idea what NSSplitViewController is, but presumably you can get access to the NSSplitView via its view property, or some such.

Answer 2

Rather than looking at it as a resize, it sounds like you're simply trying to collapse/uncollapse the master view item. You can just use NSSplitViewItem's collapsed property with its animator proxy to trigger the collapse:
if (FOO) {
// Expand subViewItem (collapse the master view item)
masterViewItem.animator.collapsed = YES;
And uncollapse:
} else if (BAR) {
// Expand masterViewItem while shrinking subViewItem
masterViewItem.animator.collapsed = NO;
}
}
With 10.11, there's API to designate your master view item as a "sidebar", which has additional collapse/uncollapse behavior for that item (such as overlays).