Swift 一元运算符'';不能应用于类型为';()';
一元运算符'!'无法应用于“()”类型的操作数 在Swift 2迁移中获取此错误Swift 一元运算符'';不能应用于类型为';()';,swift,unary-operator,Swift,Unary Operator,一元运算符'!'无法应用于“()”类型的操作数 在Swift 2迁移中获取此错误 func saveContext() { if let foregroundMO = VPDataManager.sharedInstance.persistentStack.managedObjectContext { var error:NSError? = nil; let managedObjectContext: NSManagedObjectConte
func saveContext() {
if let foregroundMO = VPDataManager.sharedInstance.persistentStack.managedObjectContext
{
var error:NSError? = nil;
let managedObjectContext: NSManagedObjectContext = foregroundMO
managedObjectContext.mergePolicy = NSOverwriteMergePolicy
if (managedObjectContext.hasChanges) && !(managedObjectContext.save())
{
VPAnalytics.leaveBreadcrumb("AppDelegate saveContext critical error: \(error), \(error?.userInfo)")
logError("Unresolved issue: \(error), \(error?.userInfo)")
abort()
}
}
}
错误发生在if(managedObjectContext.hasChanges
..上,因为该方法没有返回值:
func save() throws
失败时会抛出一个错误,因此您可以像这样检查save
是否成功:
func saveContext () {
if managedObjectContext.hasChanges {
do {
try managedObjectContext.save()
} catch {
// 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.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
}
}
.save()
是否返回bool
?请注意,额外的括号使错误消息复杂化。