Bool value not being sent to destination ViewController - ios

Question

I want to send a bool value, didAddNewItem, from my SearchViewController to MatchCenterViewController, and then run a function depending on the state of the bool value. I attempt to send a didAddNewItem value of YES to my destination, MatchCenterViewController, but it doesn't seem to send correctly, as the function below never runs.
Here's how I'm sending it from SearchViewController (edited to reflect Rob's answer):
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"ShowMatchCenterSegue"]) {
_didAddNewItem = YES;
MatchCenterViewController *controller = (MatchCenterViewController *) segue.destinationViewController;
NSLog(#"we're about to set controller values before segueing to MC");
// Send over the matching item criteria
controller.itemSearch = self.itemSearch.text;
controller.matchingCategoryId = self.matchingCategoryId1;
controller.matchingCategoryMinPrice = self.matchingCategoryMinPrice1;
controller.matchingCategoryMaxPrice = self.matchingCategoryMaxPrice1;
controller.matchingCategoryCondition = self.matchingCategoryCondition1;
controller.matchingCategoryLocation = self.matchingCategoryLocation1;
controller.itemPriority = self.itemPriority;
[self.tabBarController setSelectedIndex:1];
}
}
And here's where I try to make use of it in the destination, MatchViewController:
- (void)viewDidAppear:(BOOL)animated
{
if (_didAddNewItem == YES) {
NSLog(#"well then lets refresh the MC");
// Start loading indicator
UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityIndicator.center = CGPointMake(self.view.frame.size.width / 2.0, self.view.frame.size.height / 2.0);
[self.view addSubview: activityIndicator];
[activityIndicator startAnimating];
// Disable ability to scroll until table is MatchCenter table is done loading
self.matchCenter.scrollEnabled = NO;
_matchCenterDone = NO;
// Add new item to MatchCenter Array with the criteria from the matching userCategory instance, plus the search term
[PFCloud callFunctionInBackground:#"addToMatchCenter"
withParameters:#{
#"searchTerm": self.itemSearch,
#"categoryId": self.matchingCategoryId,
#"minPrice": self.matchingCategoryMinPrice,
#"maxPrice": self.matchingCategoryMaxPrice,
#"itemCondition": self.matchingCategoryCondition,
#"itemLocation": self.matchingCategoryLocation,
#"itemPriority": self.itemPriority,
}
block:^(NSString *result, NSError *error) {
if (!error) {
NSLog(#"'%#'", result);
self.matchCenterArray = [[NSArray alloc] init];
[PFCloud callFunctionInBackground:#"MatchCenter3"
withParameters:#{}
block:^(NSArray *result, NSError *error) {
if (!error) {
_matchCenterArray = result;
[_matchCenter reloadData];
[activityIndicator stopAnimating];
// Reenable scrolling/reset didAddNewItem bool
_matchCenterDone = YES;
self.matchCenter.scrollEnabled = YES;
//_didAddNewItem = NO;
NSLog(#"Result: '%#'", result);
}
}];
}
}];
}
}
I made sure it was properly setup as a property in the headers of both ViewControllers, so I'm not sure why it's not setting the value in the destination VC correctly. I know for a fact that addToMatchCenter function is running correctly without error, so it should be working.
#property (assign) BOOL didAddNewItem;

Answer 1

In your prepareForSegue, you are calling callFunctionInBackground asynchronously, meaning that it is quite likely that the segue will finish and the new view controller will be presented well before you set didAddNewItem in the block of callFunctionInBackground.
I'd be inclined to change that destination controller to initiate this asynchronous request itself, but have it show a UIActivityIndicatorView (or something) to suggest that the dependent request has not yet been finished, and then in the block you can remove the activity indicator view and update the UI accordingly.