NSOutlineView数据源

Question

我在Xcode中创建了一个NSOutlineView(源码列表)，为它提供了一个插座，并让我的类实现了NSOutlineViewDataSource。然后我使用[outlineview setDataSource:]，我看到它创建的单元格具有我的数组中的项数，但它们都是空的。

sub1 = [NSArray arrayWithObjects:@"General Data",@"Most Played", @"Misc",@"Log", nil];
sub2 = [NSArray arrayWithObjects:@"General Data", @"Most Played", @"Misc",@"Log", nil];

items = [NSArray arrayWithObjects:sub1,sub2,nil];

[outlin setDataSource:self];
[outlin reloadData];

- (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item
{        
    return [self outlineView:outlineView numberOfChildrenOfItem:item] != 0;
}

- (NSInteger)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item
{    
    if (item)
        if ([item isKindOfClass:[NSArray class]])
            return [item count];
        else
            return 0;
    else
        return [items count];
}

- (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index ofItem:(id)item
{
    if (item) {
        return [item objectAtIndex:index];
    }
    else
        return [items objectAtIndex:index];
}

- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)theColumn byItem:(id)item
{
     if (item) {
         if ([item isKindOfClass:[NSArray class]])
             return @"YES"; // Return name for this node
         else
             return item;
     }
     else
         return @"List Root";
}

一切看起来都井然有序，有点像是在工作，除了所有的文本都是空白的。它创建所有的根项目，等等，只是没有文本。

Answer 1

也许您忘记为您的NSOutlineView构建一个表列，如下所示：

NSTableColumn *titleColumn = [[[NSTableColumn alloc] initWithIdentifier:@"identifier"] autorelease];
[[titleColumn headerCell] setStringValue:@"Header"];
[self addTableColumn:titleColumn];
[self setOutlineTableColumn:titleColumn];