藍(lán)牙實現(xiàn)流程：

1.建立中心管理者
2.掃描外設(shè)
3.連接外設(shè)
4.掃描外設(shè)的服務(wù)和特征
5.與外設(shè)進(jìn)行數(shù)據(jù)交互

代碼實現(xiàn)：

第一：建立中心管理者
首先：導(dǎo)入#import <CoreBluetooth/CoreBluetooth.h>框架
初始化CBCentralManager對象并設(shè)置代理以及隊列掘猿，queue：nil素征，默認(rèn)就是在主線程

<CBCentralManagerDelegate>
@property (nonatomic, strong) CBCentralManager *centralManager;
self.centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:dispatch_get_main_queue()];

接著調(diào)用CBCentralManagerDelegate必須實現(xiàn)的方法- (void)centralManagerDidUpdateState:(CBCentralManager *)central

- (void)centralManagerDidUpdateState:(CBCentralManager *)central {
switch (central.state) {
            case CBCentralManagerStateUnknown:
                NSLog(@"CBCentralManagerStateUnknown");
                break;
            case CBCentralManagerStateResetting:
                NSLog(@"CBCentralManagerStateResetting");
                break;
            case CBCentralManagerStateUnsupported:
                NSLog(@"CBCentralManagerStateUnsupported");
                break;
            case CBCentralManagerStateUnauthorized:
                NSLog(@"CBCentralManagerStateUnauthorized");
                break;
            case CBCentralManagerStatePoweredOff:
                NSLog(@"CBCentralManagerStatePoweredOff");
                break;
            case CBCentralManagerStatePoweredOn:
                NSLog(@"CBCentralManagerStatePoweredOn");
                break;
            default:
                break;
        }
}

第二：掃描外設(shè)

- (void)centralManagerDidUpdateState:(CBCentralManager *)central {
    if (central.state == CBCentralManagerStatePoweredOn) {
        //掃描外設(shè)，第一個參數(shù)：nil州泊，表示掃描所有外設(shè)励背，也可以根據(jù)CBUUID數(shù)組查找指定外設(shè)
        [self.centralManager scanForPeripheralsWithServices:nil options:nil];
    } else {
        NSLog(@"請打開藍(lán)牙");
    }
}

掃描到外設(shè)之后，會調(diào)用此方法

- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary<NSString *, id> *)advertisementData RSSI:(NSNumber *)RSSI {
  //連接外設(shè)
}

第三：連接外設(shè)

@property (nonatomic, strong) CBPeripheral *peripheral;
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary<NSString *, id> *)advertisementData RSSI:(NSNumber *)RSSI {
    NSLog(@"找到藍(lán)牙外設(shè) 名稱：%@",peripheral.name);
    
    if ([peripheral.name isEqualToString:@"要連接的藍(lán)牙名稱"]) {
        //這里要注意一點：peripheral在該方法里不被持有斗搞，調(diào)用結(jié)束后會被自動摧毀指攒，保存外設(shè)，使其被持有
        self.peripheral = peripheral;
        //連接外設(shè)
        [self.centralManager connectPeripheral:peripheral options:nil];
    } else {
        NSLog(@"未找到要連接的外設(shè)");
    }
}

connectPeripheral方法后會執(zhí)行以下代理方法

//外設(shè)連接成功
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {
    NSLog(@"連接藍(lán)牙成功");
    //設(shè)置代理以及查找服務(wù)
    [peripheral setDelegate:self];
    [peripheral discoverServices:nil];
}

//外設(shè)連接失敗
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
    NSLog(@"連接失敗");
}

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

第四：掃描外設(shè)的服務(wù)和特征

- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {
    NSLog(@"連接藍(lán)牙成功");
    //設(shè)置代理<CBPeripheralDelegate>以及查找服務(wù)
    [peripheral setDelegate:self];
    [peripheral discoverServices:nil];
}
#pragma mark- CBPeripheralDelegate
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {
    if (error) {
        NSLog(@"error: %@",error);
        return;
    }
    for (CBService *service in peripheral.services) {
        //掃描服務(wù)中的特征
        [peripheral discoverCharacteristics:nil forService:service];
    }
}

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error {
    for (CBCharacteristic *characteristics in service.characteristics) {
        if ([characteristics.UUID isEqual:[CBUUID UUIDWithString:@"writeUUID"]]) {
            //向外設(shè)發(fā)送數(shù)據(jù)：data
            [peripheral writeValue:[NSData data] forCharacteristic:characteristics type:CBCharacteristicWriteWithResponse];
        } else if ([characteristics.UUID isEqual:[CBUUID UUIDWithString:@"readUUID"]]) {
            [peripheral readValueForCharacteristic:characteristics];
        } else if ([characteristics.UUID isEqual:[CBUUID UUIDWithString:@"notifyUUID"]]) {
            [peripheral setNotifyValue:YES forCharacteristic:characteristics];
        }
    }
}

第五：與外設(shè)進(jìn)行數(shù)據(jù)交互

[self.peripheral writeValue:[NSData data] forCharacteristic:characteristics type:CBCharacteristicWriteWithResponse];

//獲取characteristic的值
- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    NSLog(@"收到數(shù)據(jù)：%@",characteristic.value);
    //此處對外設(shè)返回的數(shù)據(jù)進(jìn)行處理
    
}