刪除列表後，UITableView將不會刷新。 self.tableView.reloadData（）不起作用

Question

我對開發Swift和iOS相對比較陌生，但並不是新的代碼。我有點討厭表格視圖。

我已經試過無數次使用self.tableView.reloadData()但無濟於事。我也試過

async call dispatch_async(dispatch_get_main_queue()) { 
    self.tableView.reloadData() 
} 

但是這也不想工作。我會發布功能，以便有人可以啓發我在哪裏搞錯了。我真的很感激幫助。

@IBAction func clearList(sender: AnyObject) { 
    let alert = UIAlertController(title: "Clear List?", 
    message: "Are you sure you want to clear the list?", 
    preferredStyle: .Alert) 

    let yesClearAction = UIAlertAction(title: "Yes", style: .Default, handler: { (action:UIAlertAction) -> Void in 
    self.clearListNow("GroceryList") 

    }) 

    let noClearAction = UIAlertAction(title: "No", style: .Default, handler: { (action:UIAlertAction) -> Void in 
     //do nothing aka don't clear list 
    }) 
    alert.addAction(yesClearAction) 
    alert.addAction(noClearAction) 

    presentViewController(alert, animated: true, completion: nil) 

    self.tableView.reloadData() 
} 

以防萬一有人想看看有什麼clearListNow呢......

func clearListNow(entity: String) { 
    let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate 
    let managedContext = appDelegate.managedObjectContext 
    let fetchRequest = NSFetchRequest(entityName: "GroceryList") 
    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)") 
    } 
} 

我也試圖在clearListNow功能使用self.tableView.reloadData()。我試圖在同一時間和兩種情況下單獨陳述陳述，並且兩種情況都沒有奏效。

Answer 1

刷新你的tableView當如圖到下面的代碼使用按是在提醒：

let yesClearAction = UIAlertAction(title: "Yes", style: .Default, handler: { (action:UIAlertAction) -> Void in 

     self.clearListNow("GroceryList") 
     self.tableView.reloadData() 

}) 

Answer 2

嘗試yesClearAction 重新加載數據，你應該有這樣的：

@IBAction func clearList(sender: AnyObject) { 
    let alert = UIAlertController(title: "Clear List?", 
    message: "Are you sure you want to clear the list?", 
    preferredStyle: .Alert) 

    let yesClearAction = UIAlertAction(title: "Yes", style: .Default, handler: {(action:UIAlertAction) -> Void in 
    self.clearListNow("GroceryList") 
    self.tableView.reloadData() 
}) 

let noClearAction = UIAlertAction(title: "No", style: .Default, handler: { (action:UIAlertAction) -> Void in 
    //do nothing aka don't clear list 
}) 
alert.addAction(yesClearAction) 
alert.addAction(noClearAction) 
presentViewController(alert, animated: true, completion: nil) 
} 

讓我知道如果這工作！ :)

UPDATE

我已經做了這個代碼，它爲我

import UIKit 

class ViewController: UIViewController ,UITableViewDelegate, UITableViewDataSource{ 

@IBOutlet weak var tableView: UITableView! 
var rows: NSMutableArray! 

override func viewDidLoad() { 
    super.viewDidLoad() 
    self.rows = ["1","2","3","4","5","6","7"] 
    self.tableView.reloadData() 

} 

override func didReceiveMemoryWarning() { 
    super.didReceiveMemoryWarning() 
    // Dispose of any resources that can be recreated. 
} 

@IBAction func clearList(sender: AnyObject) { 
    let alert = UIAlertController(title: "Clear List?", 
     message: "Are you sure you want to clear the list?", 
     preferredStyle: .Alert) 

    let yesClearAction = UIAlertAction(title: "Yes", style: .Default, handler: { (action:UIAlertAction) -> Void in 
     self.clearListNow("GroceryList") 
     self.tableView.reloadData() 

    }) 

    let noClearAction = UIAlertAction(title: "No", style: .Default, handler: { (action:UIAlertAction) -> Void in 
     //do nothing aka don't clear list 
    }) 
    alert.addAction(yesClearAction) 
    alert.addAction(noClearAction) 

    presentViewController(alert, animated: true, completion: nil) 


} 

func clearListNow(entity: String) { 
    self.rows.removeAllObjects() 
} 

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int{ 
    return self.rows.count 
} 


func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{ 
    let cell = tableView.dequeueReusableCellWithIdentifier("FruitCell", forIndexPath: indexPath) as? MyCell 
    cell!.textLabel?.text = self.rows[indexPath.row] as? String 
    return cell! 
} 

} 

我在這裏的故事板的屏幕截圖正常工作：

Answer 3

按你當前的代碼在AlertView後重新加載TableView Reload so，tableView Da taSource（數組）不改變和tableview顯示數據源（數組）數據。

嘗試後

self.clearListNow("GroceryList") 

即

self.clearListNow("GroceryList") 
self.tableView.reloadData() 

或

成FUNC clearListNow到relod表（實體：字符串）

for循環 即後

for managedObject in results 
{ 
let managedObjectData:NSManagedObject = managedObject as! NSManagedObject 
managedContext.deleteObject(managedObjectData) 
} 
self.tableView.reloadData() 

so tableview獲取最新的數據源並顯示它。

讓我知道，如果這個工程...