I would use KVO (Key Value Observing) to keep track of when it changes:

 - (void)viewDidLoad {
      [super viewDidLoad];  

      // Note that you can use the options to get the new value passed when it
      // changes if you want to update immediately.
      [configurationObject addObserver:self forKeyPath:@"configurationItem" options:0 context:nil];
 }

 - (void)viewDidUnload {
      [super viewDidUnload];
      [configurationObject removeObserver:self forKeyPath:@"configurationItem"];
 }

 // Note that I would refresh in viewWillAppear instead of viewDidAppear
 - (void)viewWillAppear:(BOOL)animated {
      [super viewWillAppear:animated];
      if (self.needToRefreshData == YES) {
           [self.tableView refreshData];
      }
 }

 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
      if (keyPath isEqualToString:@"configurationItem") {
           [self.needToRefreshData = YES];
      }
 }

利用代表团设计模式将数据从一名主计长转给另一名主计长。

例如,我要说的是,塔布罗克有一辆可贵的电算器上的汽车清单,你有另一种看法,即让用户在名单上添加一辆新车。 您可以允许UITableViewController

• Adopt AddCarViewController s protocol
• Set itself as a Delegate for AddCarViewController s protocol
• Implement its protocol method
• Execute the protocol method when informed

You can then let the AddCarViewController

• Create a Protocol
• Declare object reference Delegate with getter and setter methods
• Define a method under that protocol
• Inform the Delegate when the Save action is performed

检查贵邮电号以下样本代码

@interface ViewController : UITableViewController <AddCarViewControllerDelegate>

             :
             :

// The addCar: method is invoked when the user taps the Add button created at run time.
- (void)addCar:(id)sender
{
// Perform the segue named ShowAddCar
[self performSegueWithIdentifier:@"ShowAddCar" sender:self];
}

             :
             :

// This method is called by the system whenever you invoke the method     performSegueWithIdentifier:sender:
// You never call this method. It is invoked by the system.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    NSString *segueIdentifier = [segue identifier];

    if ([segueIdentifier isEqualToString:@"ShowAddCar"]) {

        // Obtain the object reference of the destination view controller
        AddCarViewController *addCarViewController = [segue destinationViewController];

        // Under the Delegation Design Pattern, set the addCarViewController s delegate to be self
        addCarViewController.delegate = self;

        // Instantiate a Save button to invoke the save: method when tapped
        UIBarButtonItem *saveButton = [[UIBarButtonItem alloc]
                                       initWithBarButtonSystemItem:UIBarButtonSystemItemSave
                                       target:addCarViewController action:@selector(save:)];

        // Set up the Save custom button on the right of the navigation bar
        addCarViewController.navigationItem.rightBarButtonItem = saveButton;

    }

}

                 :
                 :


- (void)addCarViewController:(AddCarViewController *)controller didFinishWithSave:    (BOOL)save {
                 :
                 :
}

The Sample Code for the AddCarViewController is here

@protocol AddCarViewControllerDelegate;

@interface AddCarViewController : UIViewController

@property (nonatomic, strong) IBOutlet UITextField *carMake;
@property (nonatomic, strong) IBOutlet UITextField *CarName;
@property (nonatomic, assign) id <AddCarViewControllerDelegate> delegate;

// The keyboardDone: method is invoked when the user taps Done on the keyboard
- (IBAction)keyboardDone:(id)sender;

// The save: method is invoked when the user taps the Save button created at run time.
- (void)save:(id)sender;

@end

/*
 The Protocol must be specified after the Interface specification is ended.
 Guidelines:
 - Create a protocol name as ClassNameDelegate as we did above.
 - Create a protocol method name starting with the name of the class defining the protocol.
 - Make the first method parameter to be the object reference of the caller as we did below.
 */
@protocol AddCarViewControllerDelegate
- (void)addCarViewController:(AddCarViewController *)controller didFinishWithSave:(BOOL)save;
@end

一种做法是,在环境考虑主计长发现某种变化可以显示模型的变化时,采用某种共同的类别(或许是哪类代表)来跟踪你的模型,然后当有关观点得到考虑时,即认为DidAppear被点燃时,它可以询问模型,如果当时你知道要重新载上表观点,那么该国旗是否被打上了,否则你会这样做。

另一种方式是使用通知中心,如果您的意见被装上,可以签署示范变更通知,届时该通知就悬挂了国旗,表明它需要在下台时重载表格。

hope this helps

您可以储存核心数据,并使用NSFetResult。 持受扶养人观点的主计长担任代表。 这样一来,只要数据发生变化,你的观察控制员就会受到警示。

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