corebluetooth reconnect to Peripheral and discoverServices ios

Question

I'm using corebluetooth framework to connect my iphone to BLE devices. i have successfully achieved connecting to a peripheral and discovering services and characteristics as well as update value for a characteristic.

my problem begins when my BLE device is disconnected. when that happen i do the following:

1. retrievePeripheralsWithIdentifiers
2. cancelPeripheralConnection (just in case)
3. connectPeripheral once again
4. activePeripheral = peripheral
5. [activePeripheral discoverServices:services]; (i check first if the peripheral has services , but it doesn't have)

when i try to discoverServices my app crashes!!

CODE:

    NSArray *retrievePeripherals = [[PRCentralDiscoverManger sharedInstance] retrivePeripheral:@[peripheral.identifier]];
        NSLog(@"retrievePeripherals: %@",retrievePeripherals);

        for (CBPeripheral *p in retrievePeripherals)
        {
            if (peripheral == p )
            {
                for (PRPeripheralManger *pm in _serviceArray)
                {
                    if (p == pm.peripheral)
                    {
                        NSLog(@"PRPeripheralManger in _serviceArray");
                        //[[PRCentralDiscoverManger sharedInstance] disconnectPeripheral:p];
                        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                            //Here your non-main thread.
                            [NSThread sleepForTimeInterval:2.0f];
                            dispatch_async(dispatch_get_main_queue(), ^{
                                //Here you returns to main thread.
                                NSLog(@"Here you returns to main thread");

                                [[PRCentralDiscoverManger sharedInstance] connectPeripheral:peripheral];
                                service = [[PRPeripheralManger alloc]initWithPeripheral:peripheral controller:self];
                                [service startDiscoveringServicesWithUUIDString:uuid];
                            });
                        });

                        break;
                    }
                }
            }


        }
- (id) initWithPeripheral:(CBPeripheral *)peripheral controller:(id<PRPeripheralMangerProtocol>)controller
{


    self = [super init];
    if (self)
    {
        activePeripheral = peripheral;
        [activePeripheral setDelegate:self];
        _peripheralDelegate = controller;


    }
    return self;
}     
- (void) startDiscoveringServicesWithUUIDString:(NSString *)uuidString
{
    NSLog(@"startDiscoveringServicesWithUUIDString peripheral:%@",activePeripheral); //EXSIST
    NSLog(@"startDiscoveringServicesWithUUIDString services :%@",activePeripheral.services); // ALWAYS NULL

    if (activePeripheral.services)
    {
        NSLog(@"activePeripheral.services: %@",activePeripheral.services);

        [self peripheral:activePeripheral didDiscoverServices:nil];
    }
    else
    {
        if (uuidString)
        {
            NSLog(@"discoverServices: %@",uuidString);
            NSArray *services = @[[CBUUID UUIDWithString:uuidString]];
            [activePeripheral discoverServices:services];//CRASHES HERE
        }
        else
        {
            NSLog(@"discoverServices:nil");

            [activePeripheral discoverServices:nil];
        }
    }
}  

CRASH LOG:

* thread #1: tid = 0x58f4, 0x30b00f46 libobjc.A.dylib`objc_msgSend + 6, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xc000000c)
frame #0: 0x30b00f46 libobjc.A.dylib`objc_msgSend + 6
frame #1: 0x230142ac CoreBluetooth`-[CBPeripheral handleServicesDiscovered:] + 620
frame #2: 0x230122b6 CoreBluetooth`-[CBPeripheral handleMsg:args:] + 282
frame #3: 0x2300e674 CoreBluetooth`-[CBCentralManager xpcConnection:didReceiveMsg:args:] + 256
frame #4: 0x23019356 CoreBluetooth`__34-[CBXpcConnection handleMsg:args:]_block_invoke + 54
frame #5: 0x002fb9da libdispatch.dylib`_dispatch_call_block_and_release + 10
frame #6: 0x002fb9c6 libdispatch.dylib`_dispatch_client_callout + 22
frame #7: 0x00303e28 libdispatch.dylib`_dispatch_queue_drain + 1092
frame #8: 0x002fe2c8 libdispatch.dylib`_dispatch_queue_invoke + 88
frame #9: 0x002ff21e libdispatch.dylib`_dispatch_main_queue_callback_4CF + 346
frame #10: 0x233003b0 CoreFoundation`__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 8
frame #11: 0x232feab0 CoreFoundation`__CFRunLoopRun + 1512
frame #12: 0x2324c3c0 CoreFoundation`CFRunLoopRunSpecific + 476
frame #13: 0x2324c1d2 CoreFoundation`CFRunLoopRunInMode + 106
frame #14: 0x2a64a0a8 GraphicsServices`GSEventRunModal + 136
frame #15: 0x2685a7b0 UIKit`UIApplicationMain + 1440

im really new to stackoverflow sorry if this is not the way to present the question.

Answer 1

You should pair your iphone with peripheral device. Then settings app will reconnect to peripheral when it disconnect.