CBCentralManager connecting to a CBPeripheralManager, connects then disconnects? - ios

Question

I have an iOS device (iPod Touch 5G) acting as a CBCentralManager, and Bluno acting as a CBPeripheralManager. When I attempt to connect to the peripheral with the central it appears to connect for a second or two then disconnects. I can see a LED on the Bluno light up for a second or two then dim down. I know there isn't a problem with the Bluno because I can use the LightBlue app on the iPod Touch to connect to the peripheral. So the problem probably lies somewhere in my code.
As of right now, I am getting the following message when I status syslog,
CoreBluetooth[WARNING] <CBCentralManager: 0x16e77470> is disabling duplicate filtering, but is using the default queue (main thread) for delegate events
Not sure if that is related to the connect / disconnect problem.
The code I have constructed is as follows,
Services.h
#define BLUNO_TRANSFER_SERVICE_UUID #"0xDFB0"
#define BLUNO_TRANSFER_CHARACTERISTIC_UUID #"0xDFB2"
ViewControllerDev2.h
#import <Foundation/Foundation.h>
#import <CoreBluetooth/CoreBluetooth.h>
#import <QuartzCore/QuartzCore.h>
#import "SERVICES.h"
#interface ViewControllerDev2 : UIViewController <CBCentralManagerDelegate, CBPeripheralDelegate, UITextViewDelegate> {
}
#property (weak, nonatomic) IBOutlet UIBarButtonItem *btnDone;
// Core Bluetooth Peripheral stuff
#property (strong, nonatomic) CBCentralManager *centralManager;
#property (strong, nonatomic) CBPeripheral *discoveredPeripheral;
#property (strong, nonatomic) NSMutableData *data;
#property (strong, nonatomic) IBOutlet UITextView *textView;
#property (weak, nonatomic) IBOutlet UIButton *btnSend;
- (IBAction)dismissScene:(id)sender;
- (IBAction)sendBTData:(id)sender;
#end
ViewControllerDev2.m
#import "ViewControllerDev2.h"
#implementation ViewControllerDev2
- (void)viewDidLoad
{
[super viewDidLoad];
_centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil options:nil]; // options:nil is an iOS 7 feature
_data = [[NSMutableData alloc] init];
}
- (void)viewDidUnload {
[self setBtnDone:nil];
[super viewDidUnload];
}
- (IBAction)sendBTData:(id)sender {
//[self sendData];
}
- (IBAction)dismissScene:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
[_centralManager stopScan];
}
- (void)centralManagerDidUpdateState:(CBCentralManager *)central
{
// You should test all scenarios
if (central.state != CBCentralManagerStatePoweredOn) {
return;
}
if (central.state == CBCentralManagerStatePoweredOn) {
// Scan for devices
[_centralManager scanForPeripheralsWithServices:#[[CBUUID UUIDWithString:BLUNO_TRANSFER_SERVICE_UUID]] options:#{ CBCentralManagerScanOptionAllowDuplicatesKey : #YES }];
NSLog(#"Scanning started");
}
}
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {
NSLog(#"Discovered %# at %#", peripheral.name, RSSI);
if (_discoveredPeripheral != peripheral) {
// Save a local copy of the peripheral, so CoreBluetooth doesn't get rid of it
_discoveredPeripheral = peripheral;
// And connect
NSLog(#"Connecting to peripheral %#", peripheral);
[_centralManager connectPeripheral:peripheral options:nil];
// then stop scanning for peripherals
[_centralManager stopScan];
NSLog(#"Scanning stopped");
}
}
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
NSLog(#"Failed to connect");
[self cleanup];
}
- (void)cleanup {
// See if we are subscribed to a characteristic on the peripheral
if (_discoveredPeripheral.services != nil) {
for (CBService *service in _discoveredPeripheral.services) {
if (service.characteristics != nil) {
for (CBCharacteristic *characteristic in service.characteristics) {
if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:BLUNO_TRANSFER_CHARACTERISTIC_UUID]]) {
if (characteristic.isNotifying) {
[_discoveredPeripheral setNotifyValue:NO forCharacteristic:characteristic];
return;
}
}
}
}
}
}
[_centralManager cancelPeripheralConnection:_discoveredPeripheral];
}
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {
NSLog(#"Connected");
[_centralManager stopScan];
NSLog(#"Scanning stopped");
[_data setLength:0];
peripheral.delegate = self;
[peripheral discoverServices:#[[CBUUID UUIDWithString:BLUNO_TRANSFER_SERVICE_UUID]]];
}
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {
if (error) {
[self cleanup];
return;
}
for (CBService *service in peripheral.services) {
[peripheral discoverCharacteristics:#[[CBUUID UUIDWithString:BLUNO_TRANSFER_CHARACTERISTIC_UUID]] forService:service];
}
// Discover other characteristics
}
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error {
if (error) {
[self cleanup];
return;
}
for (CBCharacteristic *characteristic in service.characteristics) {
if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:BLUNO_TRANSFER_CHARACTERISTIC_UUID]]) {
[peripheral setNotifyValue:YES forCharacteristic:characteristic];
}
}
}
- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
if (error) {
NSLog(#"Error");
return;
}
NSString *stringFromData = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];
// Have we got everything we need?
if ([stringFromData isEqualToString:#"EOM"]) {
//[_textview setText:[[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding]];
[peripheral setNotifyValue:NO forCharacteristic:characteristic];
[_centralManager cancelPeripheralConnection:peripheral];
}
[_data appendData:characteristic.value];
}
- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
if (![characteristic.UUID isEqual:[CBUUID UUIDWithString:BLUNO_TRANSFER_CHARACTERISTIC_UUID]]) {
return;
}
if (characteristic.isNotifying) {
NSLog(#"Notification began on %#", characteristic);
} else {
// Notification has stopped
[_centralManager cancelPeripheralConnection:peripheral];
}
}
- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
_discoveredPeripheral = nil;
[_centralManager scanForPeripheralsWithServices:#[[CBUUID UUIDWithString:BLUNO_TRANSFER_SERVICE_UUID]] options:#{ CBCentralManagerScanOptionAllowDuplicatesKey : #YES }];
}
#end

Answer 1

Here's your problem:
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {
NSLog(#"Discovered %# at %#", peripheral.name, RSSI);
if (_discoveredPeripheral != peripheral) {
// Save a local copy of the peripheral, so CoreBluetooth doesn't get rid of it
_discoveredPeripheral = peripheral;
// And connect
NSLog(#"Connecting to peripheral %#", peripheral);
[_centralManager connectPeripheral:peripheral options:nil]; // <-- this is the issue
// then stop scanning for peripherals
[_centralManager stopScan];
NSLog(#"Scanning stopped");
}
}
You're connecting to a weakly held object, you should connect to your _discoveredPeripheral object instead. Also, don't forget to update your property calls to use your BCPeripheral object, for example:
[_discoveredPeripheral discoverServices:#[[CBUUID UUIDWithString:BLUNO_TRANSFER_SERVICE_UUID]]];