对于如何快速删除所有核心数据,我有点困惑。我创建了一个带有 IBAction
链接的按钮。单击按钮时,我有以下内容:
let appDel: foodforteethAppDelegate = UIApplication.sharedApplication().delegate as foodforteethAppDelegate
let context: NSManagedObjectContext = appDel.managedObjectContext
然后我弄乱了各种方法来尝试删除所有核心数据内容,但我似乎无法让它工作。我已经使用 removeAll 从存储的数组中删除,但仍然无法从核心数据中删除。我假设我需要某种类型的 for 循环,但不确定如何从请求中实现它。
我尝试应用删除单行的基本原则
func tableView(tableView: UITableView!, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath!) {
let appDel: foodforteethAppDelegate = UIApplication.sharedApplication().delegate as foodforteethAppDelegate
let context:NSManagedObjectContext = appDel.managedObjectContext
if editingStyle == UITableViewCellEditingStyle.Delete {
if let tv = tblTasks {
context.deleteObject(myList[indexPath!.row] as NSManagedObject)
myList.removeAtIndex(indexPath!.row)
tv.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: UITableViewRowAnimation.Fade)
}
var error: NSError? = nil
if !context.save(&error) {
abort()
}
}
}
但是,问题是当我单击一个按钮时,我没有 indexPath 值,而且我还需要遍历所有我似乎无法使用上下文处理的值。
最佳答案
试试这个简单的解决方案:
func deleteAllData(entity: String)
{
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
let fetchRequest = NSFetchRequest(entityName: entity)
fetchRequest.returnsObjectsAsFaults = false
do
{
let results = try managedContext.executeFetchRequest(fetchRequest)
for managedObject in results
{
let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
managedContext.deleteObject(managedObjectData)
}
} catch let error as NSError {
print("Detele all data in \(entity) error : \(error) \(error.userInfo)")
}
}
swift 4
func deleteAllData(_ entity:String) {
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: entity)
fetchRequest.returnsObjectsAsFaults = false
do {
let results = try dataController.viewContext.fetch(fetchRequest)
for object in results {
guard let objectData = object as? NSManagedObject else {continue}
dataController.viewContext.delete(objectData)
}
} catch let error {
print("Detele all data in \(entity) error :", error)
}
}
实现:
self.deleteAllData("your_entityName")
关于iOS:删除所有核心数据 Swift,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/24658641/