如何更改NSOutlineView DisclosureButt

NSOutlineView默认的DisclosureButton是在左边，如下图所示： 屏幕快照 2019-01-06 下午7.20.35.png

现在需要将其更改为在右边，并将其图片更改：

屏幕快照 2019-01-06 下午7.22.42.png

实现方法如下
1 自定义NSOutlineView

@interface LYOutlineView : NSOutlineView
@end

2 重写- (void)layout方法

    [super layout];
    for (NSView *view in self.subviews) {
        for (NSView *subView in view.subviews) {
            if ([subView.identifier isEqualToString:NSOutlineViewDisclosureButtonKey]) {
                // 设置图片
                NSButton *disclosure = (NSButton *)subView;
                disclosure.imageScaling = NSImageScaleProportionallyUpOrDown;
                disclosure.image = [NSImage imageNamed:@"jiantouyou"];
                disclosure.alternateImage = [NSImage imageNamed:@"jiantouxia"];
                // 设置frame
                CGFloat x = view.frame.size.width - 100;
                CGFloat y = disclosure.frame.origin.y;
                [disclosure setFrameOrigin:NSMakePoint(x, y)];
            }
        }
    }