如何在基于视图的 NSOutlineView 中自定义披露单元格 [英] How to customize disclosure cell in view-based NSOutlineView

问题描述

我正在尝试在基于视图的 NSOutlineView 中自定义显示箭头外观.我看到推荐使用

I'm trying to customize the disclosure arrow appearance in my view-based NSOutlineView. I saw that it's recommended to use

- (void)outlineView:(NSOutlineView *)outlineView willDisplayOutlineCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn item:(id)item

委托方法来实现它.问题是由于某种原因没有调用此方法.我有 2 个自定义单元格视图 - 一个用于项目，第二个用于标题项目.对于基于视图的大纲视图，可能不会调用此方法?可能是 Lion 中的某些东西损坏了?

delegate method to achieve it. The problem is that this method is not called for some reason. I have 2 custom cell views - one for item and second for header item. May be this method is not called for view-based outline views? May be something became broken in Lion?

请说明一下.

推荐答案

这个答案是针对 OS X 10.7 编写的，对于较新版本的 OS X/macOS，请参考 WetFish 的回答

该方法不会被调用，因为它只与基于单元格的大纲视图相关.

That method does not get called because it is only relevant for cell based outline views.

在基于视图的大纲视图中，显示三角形是可展开行的行视图中的常规按钮.我不知道它是在哪里添加的，但它确实存在，并且 NSView 的 didAddSubview: 方法准确地处理了将视图添加到其他地方的情况.

In a view based outline view, the disclosure triangle is a regular button in the row view of expandable rows. I don't know where it gets added, but it does, and NSView's didAddSubview: method handles exactly that situation of a view being added somewhere else.

因此，子类化 NSTableRowView，并覆盖 didAddSubview:，像这样:

Hence, subclass NSTableRowView, and override didAddSubview:, like this:

-(void)didAddSubview:(NSView *)subview
{
    // As noted in the comments, don't forget to call super:
    [super didAddSubview:subview];

    if ( [subview isKindOfClass:[NSButton class]] ) {
        // This is (presumably) the button holding the 
        // outline triangle button.
        // We set our own images here.
        [(NSButton *)subview setImage:[NSImage imageNamed:@"disclosure-closed"]];
        [(NSButton *)subview setAlternateImage:[NSImage imageNamed:@"disclosure-open"]];
    }
}

当然，您的大纲视图的委托必须实现 outlineView:rowViewForItem: 以返回新的行视图.

Of course, your outline view's delegate will have to implement outlineView:rowViewForItem: to return the new row view.

尽管名称如此，NSOutlineView 的 frameOfOutlineCellAtRow: 仍然会被调用以获取基于视图的轮廓视图，因此对于三角形的定位，您可能需要子类化轮廓视图并覆盖该方法.

Despite the name, frameOfOutlineCellAtRow: of NSOutlineView still gets called for view based outline views, so for the positioning of your triangle, you might want to subclass the outline view and override that method, too.

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