Ios 无法将我的fetchedresultscontroller变量转换为swift 3

我想把它转换成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
}()

但它将其转化为：

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
}()

lazy var fetchedResultsController:NSFetchedResultsController={（）->in
let fetchRequest=NSFetchRequest（entityName:“Mesages”）
fetchRequest.sortDescriptors=[NSSortDescriptor（键：“timestamp”，升序：true）]
fetchRequest.predicate=NSPredicate（格式：“user.id=%@”，self.friend！.id！）
让moc=（UIApplication.shared.delegate为！AppDelegate）.managedObjectContext
设frc=NSFetchedResultsController（fetchRequest:fetchRequest，managedObjectContext:moc，sectionNameKeyPath:nil，cacheName:nil）
frc.delegate=self
返回frc
}()

---

在随机位置放置分号会产生错误，您如何在swift 3中声明类似的内容？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
}()

惰性变量fetchedResultsController:NSFetchedResultsController={
let fetchRequest=NSFetchRequest（entityName:“Mesages”）
fetchRequest.sortDescriptors=[NSSortDescriptor（键：“timestamp”，升序：true）]
fetchRequest.predicate=NSPredicate（格式：“user.id=%@”，self.friend！.id！）
让moc=（UIApplication.shared.delegate为！AppDelegate）.managedObjectContext
设frc=NSFetchedResultsController（fetchRequest:fetchRequest，managedObjectContext:moc，sectionNameKeyPath:nil，cacheName:nil）
frc.delegate=self
返回frc
}()

尽管您需要在谓词中永久性地展开它，但为什么要将

友元

及其

id

声明为可选？