所以,将我的代码迁移到
Swift 3有点卡住了.现在NSBatchDeleteRequest需要iOS 10吗？我可以使用以下代码段构建代码的唯一方法是：
func removeAllChargerData(){
// Remove all charging data from persistent storage
let fetchRequest: NSFetchRequest<NSFetchRequestResult> = ChargerPrimary.fetchRequest()
let entity = NSEntityDescription.entity(forEntityName: "ChargerPrimary",in: self.secondMoc)
fetchRequest.entity = entity
let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
do {
try self.secondMoc.execute(deleteRequest)
} catch {
let deleteError = error as NSError
NSLog("\(deleteError),\(deleteError.localizedDescription)")
}
}
但是,会显示一条警告,指示fetchRequest()仅在iOS 10和更高版本中可用.如果我以下列方式定义fetchRequest,我会收到一个错误,因为它希望fetchRequest具有一个NSFetchRequestResult参数类型：
let fetchRequest = NSFetchRequest<ChargerPrimary>(entityName: "ChargerPrimary")
解决方法
您只需要为通用指定正确的类型：
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ChargerPrimary")