小编Ol *_*Sen的帖子

无法弄清楚如何在swift中重写以下方法以 获得更好的学习曲线,所以我试图翻译这段代码.所以让我们选择一个更难的方法来做到这一点.它有error handling,object init并且parameter settings,一array of object pointers,selectors,nil,和self..

Objective-C的:

-(NSFetchedResultsController *)fetchedResultsController
{
    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];
    [fetchRequest setFetchBatchSize:20];

    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
    NSArray *sortDescriptors = @[sortDescriptor];
    [fetchRequest setSortDescriptors:sortDescriptors];

    NSFetchedResultsController *frC = [[NSFetchedResultsController alloc]
        initWithFetchRequest:fetchRequest
        managedObjectContext:self.managedObjectContext 
        sectionNameKeyPath:nil 
        cacheName:@"Master"];
    frC.delegate = self;
    self.fetchedResultsController = frC; …