無法將我的 fetchedresultscontroller var 轉換為 swift 3

Question

我正在嘗試將其轉換為 swift 3

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.shared.delegate as! AppDelegate).managedObjectContext
    let frc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc, sectionNameKeyPath: nil, cacheName: nil)
    frc.delegate = self
    return frc
}()

但它將其轉換為：

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
}()

將分號放在隨機位置會給我帶來錯誤，你如何在 swift 3 中聲明這樣的東西

Answer 1

您需要指定ResultType

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
}()