如何使NSCollectionView在包含它的视图可见之前完成绘图?

我正在尝试清理我的应用程序(为10.5构建)上的UI,有一件事相当烦人,那就是当我切换到库时,我重新加载内容,显示项目的nscollectionview在淡入新内容之前淡出旧内容。我不介意旧/新项目的淡入/淡出,但是我编程视图交换的方式应该使库在包含nscollectionview的nsview插入主窗口之前重新加载。

以前有人有过这种问题吗?

下面是应用程序不同部分到库的交换过程的简化版本:

-(void)setMainPaneToLibrary {
    if(viewState == VIEW_STATE_LIBRARY)
        return;
    [libraryController refreshDevices:self];
    [libraryController refreshLibraryContents];

    [menuController setSelectionToIndex:0];
    viewState = VIEW_STATE_LIBRARY;

    [self removeSubview]; //clear the area
    [mainPane addSubview:[libraryController view]];
}

在库控制器中:

-(void)refreshLibraryContents {
    [self loadLibraryContents:[rootDir stringByAppendingPathComponent:currentDir]];
}

-(void)loadLibraryContents:(NSString *)folderToLoad {

    int i;
    int currentSelection = [libraryArrayController selectionIndex]; //used to preserve selection and smooth folder changing

    [libraryArrayController setContent:nil];

    //expand the path to load
    folderToLoad = [folderToLoad stringByExpandingTildeInPath];

    NSFileManager * fileManager = [NSFileManager defaultManager]; 
    //load the files in the folder
    NSArray * contents = [fileManager directoryContentsAtPath:folderToLoad];

    //create two seperate arrays for actual files and folders - allows us to add them in order
    NSMutableArray * directories = [[NSMutableArray alloc] init];
    NSMutableArray * musicFiles = [[NSMutableArray alloc] init];

//... a load of stuff filling the file arrays ...

    for(i=0;i<[directories count];i++) {
    [libraryArrayController addObject:[directories objectAtIndex:i]];
    }
    for(i=0;i<[musicFiles count];i++) {
    [libraryArrayController addObject:[musicFiles objectAtIndex:i]];
    }

    if(currentSelection >= 0) {
    [libraryArrayController setSelectionIndex:currentSelection];
    }

    [directories release];
    [musicFiles release];   
}