我观看了 WWDC 会议，阅读了有关 Swift 的新程序员书籍，并阅读了我能找到的有关 Stack Overflow 的所有相关问题。从 Swift 1.2 迁移到 Swift 2.0 后，我修复了我的应用程序中的大多数错误。
但是，仍有一些我没有设法解决。
向下转换 AnyObject
错误：
无法从“[AnyObject]”向下转换为更可选的类型“[NSManagedObject]”
代码：
let fetchRequest = NSFetchRequest(entityName: formulaEntity)
var error: NSError?
do {
let fetchedResults = try managedContext.executeFetchRequest(fetchRequest) as! [NSManagedObject]?
if let results = fetchedResults {
stocks = results
} else {
print("Could not fetch \(error), \(error!.userInfo)")
}
} catch {
print("ERROR: \(error)")
}
显示的错误发生在该let fetchedResults = try...行中
我遇到的另一个奇怪错误是在我的 AppDelegate 中：
错误：
'NSMutableDictionary' 不能转换为 '[NSObject : AnyObject]'
代码：
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("Stocks.sqlite")
var error: NSError? = nil
var failureReason = "There was an error creating or loading the application's saved data."
do {
try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch var error1 as NSError {
error = error1
coordinator = nil
// Report any error we got.
let dict = NSMutableDictionary()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error
error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict as [NSObject : AnyObject])
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
} catch {
fatalError()
}
return coordinator
}()
我从来没有接触过上面的代码。所以我不知道为什么苹果的迁移工具没有正确迁移它。
我的 AppDelegate 中的另一个错误：
二元运算符 '&&' 不能应用于两个 Bool 操作数
调用可以抛出，但它没有标记'try'并且错误没有被处理。
代码：
func saveContext () {
if let moc = self.managedObjectContext {
var error: NSError? = nil
if moc.hasChanges && !moc.save() {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
}
}
}
同样，我还没有触及 AppDelegate 的这一部分，并且不确定上面的代码到底有什么问题。