CoreBluetooth backgound - How do i reinstantiate the central manager objects in the appdelegate?

Question

I´m making an app with CoreBluetooth and i want it to run in background and perform bluetooth-related tasks.

Can someone explain me how to reinstantiate the central manager objects in the appdelegate?

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    NSArray *centralManagerIdentifiers = launchOptions[UIApplicationLaunchOptionsBluetoothCentralsKey];

    for (NSString *identifier in centralManagerIdentifiers) {

      if ([identifier isEqualToString:@"myCentral"]) {

      // what to do here?

      }
}

Answer 1

I'm assuming you're wanting to restore multiple centrals in your app delegate as described in the "Reinstantiate Your Central and Peripheral Managers" section of the documentation?

If so, I could see the didFinishLaunchingWithOptions looking something like this:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.referencesToCentrals = [NSMutableArray array];

    NSArray *centralManagerIdentifiers = launchOptions[UIApplicationLaunchOptionsBluetoothCentralsKey];
    if ((centralManagerIdentifiers) && (centralManagerIdentifiers.count > 0)) {
        // The system knows about one or more centrals that need to be restored.
        for (NSString *identifier in centralManagerIdentifiers) {
            CBCentralManager *manager = [[CBCentralManager alloc] initWithDelegate:self queue:nil options:@{CBPeripheralManagerOptionRestoreIdentifierKey : identifier}];
            [self.referencesToCentrals addObject:manager];
        }
    }
    else {
        // No centrals need to be restored.  If desired, create one for use and save a reference like this:
        CBCentralManager *manager = [[CBCentralManager alloc] initWithDelegate:self queue:nil options:@{CBPeripheralManagerOptionRestoreIdentifierKey : [[NSUUID UUID] UUIDString]}];
        [self.referencesToCentrals addObject:manager];
    }

    // Set up window, etc...
    return YES;
}

You might not want to keep a reference to all your centrals in the app delegate as I'm doing in this example nor necessarily have your app delegate act as the central's CBCentralManagerDelegate but you get the idea...