IOS / Xcode / Coredata：等效于[[self tableView] reloadData]； 什么时候没有tableview？

Question

There must be a way to update a UIViewController or view in the absence of a tableView using NSFetchedResultsController?

In this case there are some labels and a picture. I just want to refresh them with the latest data from managedobjectcontext.

Thank you.

Answer 1

[myView setNeedsDisplay]; 

will redraw the view.

[myView setNeedsLayout];

will update the layout.

Edit: After reading the comments, it's clear what you're trying to do. It's called UI Data bindings and it's not natively supported in iOS. You can search github for possible open source implementations, but I can't guarantee or recommend any since I haven't used any. My suggestion is to encapsulate the pulling and displaying of data in a function and simply call it to reload everything, especially if the reloading of the data is a result of an event:

-(void)loadDataFromDatabaseAndDisplayIt{
      NSFetchRequest* fetchRequest = [[NSFetchRequest alloc] init];
      NSEntityDescription* entity = [NSEntityDescription
                  entityForName:@"User" inManagedObjectContext:self.context];
     [fetchRequest setEntity:entity];
      NSArray* data = [self.context executeFetchRequest:fetchRequest error:&error];

      User* firstUser = data[0];

      self.labelName.text = firstUser.name;
      self.labelPhoneNumber.text = firstUser.phoneNumber;
      //...
}

-(void)viewDidLoad{
     //...
     [self loadDataFromDatabaseAndDisplayIt];
}

-(void)someEventDidOccurThatShouldReloadData:(id)sender{
     [self loadDataFromDatabaseAndDisplayIt];
}

Answer 2

What a table view's reloadData does is it calls eg cellForRowAtIndexPath a number of times, which is where you yourself add code to set the content of your labels, etc.

Similarly, you yourself will have to set the content of the labels and other UI outlets. setNeedsDisplay will only redraw the screen, not update your UI elements with data. You will have to do this "manually" in your controller.

Make a method called something like reloadViewData and reset all the labels with the current data object(s). This is not much work because presumably you have already written this code for the initial view setup. Just factor it out into this method and call it both for view setup and view update.