How to expand and collapse NSSplitView subviews with animation?

Question

Is it possible to animate the collapsing and expanding of NSSplitView subviews? (I am aware of the availability of alternative classes, but would prefer using NSSplitView ov

Answer 1

For some reason none of the methods of animating frames worked for my scrollview.

I ended up creating a custom animation to animate the divider position. This ended up taking less time than I expected. If anyone is interested, here is my solution:

Animation .h:

@interface MySplitViewAnimation : NSAnimation

@property (nonatomic, strong) NSSplitView* splitView;
@property (nonatomic) NSInteger dividerIndex;
@property (nonatomic) float startPosition;
@property (nonatomic) float endPosition;
@property (nonatomic, strong) void (^completionBlock)();

- (instancetype)initWithSplitView:(NSSplitView*)splitView
                   dividerAtIndex:(NSInteger)dividerIndex
                             from:(float)startPosition
                               to:(float)endPosition
                  completionBlock:(void (^)())completionBlock;
@end

Animation .m

@implementation MySplitViewAnimation

- (instancetype)initWithSplitView:(NSSplitView*)splitView
                   dividerAtIndex:(NSInteger)dividerIndex
                             from:(float)startPosition
                               to:(float)endPosition
                  completionBlock:(void (^)())completionBlock;
{
    if (self = [super init]) {
        self.splitView = splitView;
        self.dividerIndex = dividerIndex;
        self.startPosition = startPosition;
        self.endPosition = endPosition;
        self.completionBlock = completionBlock;

        [self setDuration:0.333333];
        [self setAnimationBlockingMode:NSAnimationNonblocking];
        [self setAnimationCurve:NSAnimationEaseIn];
        [self setFrameRate:30.0];
    }
    return self;
}

- (void)setCurrentProgress:(NSAnimationProgress)progress
{
    [super setCurrentProgress:progress];

    float newPosition = self.startPosition + ((self.endPosition - self.startPosition) * progress);

    [self.splitView setPosition:newPosition
               ofDividerAtIndex:self.dividerIndex];

    if (progress == 1.0) {
        self.completionBlock();
    }
}

@end

I'm using it like this - I have a 3 pane splitter view, and am moving the right pane in/out by a fixed amount (235).

- (IBAction)togglePropertiesPane:(id)sender
{
    if (self.rightPane.isHidden) {

        self.rightPane.hidden = NO;

        [[[MySplitViewAnimation alloc] initWithSplitView:_splitView
                                          dividerAtIndex:1
                                                  from:_splitView.frame.size.width  
                                                   to:_splitView.frame.size.width - 235                                                                                                             
                         completionBlock:^{
              ;
                                 }] startAnimation];
}
else {
    [[[MySplitViewAnimation alloc] initWithSplitView:_splitView
                                      dividerAtIndex:1                                                          
                                               from:_splitView.frame.size.width - 235
                                                 to:_splitView.frame.size.width
                                     completionBlock:^{          
        self.rightPane.hidden = YES;
                                     }] startAnimation];
    } 
}