objective-c - 如何在 NSOutlineView 中重新加载自定义 NSTableRowView？

Question

当行展开/折叠时，我正在尝试修改我的 NSOutlineView 中使用的自定义 NSTableRowView 的外观。我的 NSOutlineViewDelegate 包括:

- (NSTableRowView *)outlineView:(NSOutlineView *)outlineView rowViewForItem:(id)item
{
    ...
    return rowView;
}

- (void)itemDidExpand:(NSNotification *)notification
{
    NSDictionary *userInfo = [notification userInfo];
    id item = [userInfo objectForKey:@"NSObject"];
    NSOutlineView *outlineView = [notification object];
    [outlineView reloadItem:item];
}

不幸的是，这不会重新加载自定义行 View 。

重新加载整个 NSOutlineView 的数据:

- (void)itemDidExpand:(NSNotification *)notification
{
    [outlineView reloadData];
}

但是对于大量数据，这可能会非常耗时，并且通常会导致旋转的沙滩球。

是否可以为单个顶级项目重新加载自定义行 View ？

Answer 1

试试下面的方法:

-(void)outlineView:(NSOutlineView *)outlineView didAddRowView:(NSTableRowView *)rowView forRow:(NSInteger)row {
    aColor = [NSColor colorWithCalibratedRed:(r/255.0f) green:(g/255.0f) blue:(b/255.0f) alpha:1.0];
    [view setBackgroundColor:aColor];
}

您可以进一步推进此操作以获取行对象，然后确定特定行所需的颜色。

-编辑-

如果您希望更改父单元格 View 以显示它已展开，那么您为 NSOutlineview 实现了错误的方法。实现如下方法:

-(void)outlineViewItemWillExpand:(NSNotification *)notification {
    id theObject = [[notification userInfo] objectForKey:@"NSObject"];

    NSInteger row = [theOutlineView rowForItem:theObject];
    NSTableRowView *theRowView = [theOutlineView rowViewAtRow:row makeIfNecessary:NO];

    int r = 110;
    int g = 110;
    int b = 110;

    NSColor *aColor = [NSColor colorWithCalibratedRed:(r/255.0f) green:(g/255.0f) blue:(b/255.0f) alpha:1.0];
    [theRowView setBackgroundColor:aColor];
}