将语法转换为 swift 3.0 NSFetchedResultsController答案

【问题标题】：convert syntax to swift 3.0 NSFetchedResultsController将语法转换为 swift 3.0 NSFetchedResultsController
【发布时间】：2016-09-17 03:32:04
【问题描述】：

如何将我的 NSFetchedResultsController 转换为 swift 3.0，我无法让它工作....我尝试了苹果的自动转换，但它不起作用？？

我有这个：

lazy var fetchedResultsControler: NSFetchedResultsController = {
    let fetchRequest = NSFetchRequest(entityName: "Mesages")
    fetchRequest.sortDescriptors = [NSSortDescriptor(key: "timestamp", ascending: true)]
    fetchRequest.predicate = NSPredicate(format: "user.id = %@", self.friend!.id!)
    let moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
    let frc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc, sectionNameKeyPath: nil, cacheName: nil)
    frc.delegate = self
    return frc
}()

自动转换成这个：

    lazy var fetchedResultsControler: NSFetchedResultsController = { () -> <<error type>> in
    let fetchRequest = NSFetchRequest(entityName: "Mesages")
    fetchRequest.sortDescriptors = [NSSortDescriptor(key: "timestamp", ascending: true)]
    fetchRequest.predicate = NSPredicate(format: "user.id = %@", self.friend!.id!)
    let moc = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
    let frc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc, sectionNameKeyPath: nil, cacheName: nil)
    frc.delegate = self
    return frc
}()

但它不起作用，它要求我在随机位置放置分号

【问题讨论】：

标签： ios swift core-data nsfetchedresultscontroller

【解决方案1】：

需要在括号内设置NSFetchRequestResult.

对于 swift 3.0：

lazy var fetchedResultsControler: NSFetchedResultsController<NSFetchRequestResult> = {
    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Mesages")
    fetchRequest.sortDescriptors = [NSSortDescriptor(key: "timestamp", ascending: true)]
    fetchRequest.predicate = NSPredicate(format: "user.id = %@", self.friend!.id!)
    let moc = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
    let frc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc, sectionNameKeyPath: nil, cacheName: nil)
    frc.delegate = self
    return frc
}()

【讨论】：