iOS CoreBluetooth : centralManager:didConnectPeripheral / didFailToConnectPeripheral: not getting called - ios

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 : \n%#", 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];
}

Answer 2

var peripherals = [CBPeripheral]()
func centralManager(central: CBCentralManager, didDiscoverPeripheral peripheral: CBPeripheral, advertisementData: [String : AnyObject], RSSI: NSNumber) {
peripherals.append(peripheral)
bleManager.connectPeripheral(peripheral, options: nil)
}
This is the Swift version.