objective c - iOS CoreBluetooth : centralManager:didConnectPeripheral / didFailToConnectPeripheral: not getting called

Question

I'm pulling my hair out of this problems. I'm trying to connect to BLE devices, can't see what I've done wrong in my code below.

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    _cm = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

+ (NSString*)UUIDString:(CFUUIDRef)uuid {
    CFStringRef string = CFUUIDCreateString(NULL, uuid);
    return (__bridge_transfer NSString*)string;
}

- (void)centralManagerDidUpdateState:(CBCentralManager *)central {
    if (central.state == CBCentralManagerStatePoweredOn) {
        [self scanForPeripherals];
    }
}

- (void)centralManager:(CBCentralManager *)central
 didDiscoverPeripheral:(CBPeripheral *)peripheral
     advertisementData:(NSDictionary *)advertisementData
                  RSSI:(NSNumber *)RSSI {
//    NSLog(@"Received peripheral : 
%@", peripheral);
//    NSLog(@"Adv data : %@", advertisementData);

    [peripheral setDelegate:self];
    [central connectPeripheral:peripheral options:nil];
    [peripheral readRSSI];
}

- (int)scanForPeripherals {
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:NO], CBCentralManagerScanOptionAllowDuplicatesKey,
                             nil];

    [_cm scanForPeripheralsWithServices:nil options:options];
    return 0;
}

- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {
    NSLog(@"didConnectPeripheral");
}

- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
    NSLog(@"didDisconnectPeripheral");
}

- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
    NSLog(@"failed to connect");
}

- (void)peripheral:(CBPeripheral *)peripheral didReadRSSI:(NSNumber *)RSSI error:(NSError *)error {
    NSLog(@"didReadRSSI");
}

These devices are not my own. I don't know its proximity UUID, but as far as I know, It won't be needed in connecting via CoreBluetooth right?

All of the devices are discovered in didDiscoverPeripheral:, in the selector I tried to connect them. But there's nothing comes after that.

Am I to expect a dialog with Pairing Password Request when I called to didDiscoverPeripheral:? If so I don't see any dialog, why is that?

From apple documents, It clearly stated that after trying to connect to a device you should get a called to either didConnectPeripheral or didFailToConnectPeripher but I got none.

Any thoughts? I've been trying for almost a week now. Appreciate every helps, thanks.

Answer 1

If you don't somehow retain the peripheral object that is delivered to didDiscoverPeripheral then it is released once this delegate method exits and you won't get a connection.

I suggest adding a property to track discovered peripherals

@property (strong,nonatomic) NSMutableArray *peripherals;

initialise this in viewDidLoad or init

self.peripherals=[NSMutableArray new];

And then add the peripheral to it in didDiscoverPeripheral

-(void) centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
{
    NSLog(@"Discovered peripheral %@",peripheral.identifier.UUIDString);
    [self.peripherals addObject:peripheral];
    [central connectPeripheral:peripheral options:nil];
}