How to scan and connect to Bluetooth A2DP device on iOS programmatically

Question

I have built an Android APP which handles the scan, return nearby devices, and connect steps on both BLE and Bluetooth A2DP, and it works well. Now I'm developing the iOS version which is with exactly the same functionalities. For the BLE part, I can use CoreBluetooth to perform what I need without any problems, yet I don't know how to implement the steps of “scan -> return nearby discoverable devices -> connect” on iOS for Bluetooth A2DP device. The only solution I've found so far is to navigate to Settings page from my iOS APP and perform the connection on it. Is there any way to implement the Bluetooth A2DP connection process inside of my iOS APP programmatically?

Answer 1

in iOS, bluetooth works on central peripheral concept. below is the how it scan for nearby devices.

#import <UIKit/UIKit.h>
#import <CoreBluetooth/CoreBluetooth.h>


@interface MyViewController : UIViewController <CBPeripheralDelegate, CBCentralManagerDelegate>
{
    CBCentralManager *mgr;
}
@property (readwrite, nonatomic) CBCentralManager *mgr;
@end



- (void)viewDidLoad
{
    [super viewDidLoad];

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


- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {


    NSLog([NSString stringWithFormat:@"%@",[advertisementData description]]);
}

-(void)centralManager:(CBCentralManager *)central didRetrievePeripherals:(NSArray *)peripherals{
    NSLog(@"This is it!");
}


- (void)centralManagerDidUpdateState:(CBCentralManager *)central{ 
    NSString *messtoshow;

    switch (central.state) {
        case CBCentralManagerStateUnknown:
        {
            messtoshow=[NSString stringWithFormat:@"State unknown, update imminent."];
            break;
        }
        case CBCentralManagerStateResetting:
        {
            messtoshow=[NSString stringWithFormat:@"The connection with the system service was momentarily lost, update imminent."];
            break;
        }
        case CBCentralManagerStateUnsupported:
        {
            messtoshow=[NSString stringWithFormat:@"The platform doesn't support Bluetooth Low Energy"];
            break;
        }
        case CBCentralManagerStateUnauthorized:
        {
            messtoshow=[NSString stringWithFormat:@"The app is not authorized to use Bluetooth Low Energy"];
            break;
        }
        case CBCentralManagerStatePoweredOff:
        {
            messtoshow=[NSString stringWithFormat:@"Bluetooth is currently powered off."];
            break;
        }
        case CBCentralManagerStatePoweredOn:
        {
            messtoshow=[NSString stringWithFormat:@"Bluetooth is currently powered on and available to use."];
            [mgr scanForPeripheralsWithServices:nil options:nil];
            //[mgr retrieveConnectedPeripherals];

//--- it works, I Do get in this area!

            break;
        }   

    }
    NSLog(messtoshow); 
}