iOS蓝牙编程

蓝牙基础

• MFI --- make for ipad ,iphone, itouch
• BLE --- buletouch low energy
• RSSI --- Received Signal Strength

→_→ developer.apple.com/CoreBluetooth

下面主要是用CoreBluetooth开发。

中心（central）和外设（peripheral）

在CoreBluetooth框架下，可以看成两大模块的通信：中心(central)和外设(peripheral)。

• central
  • 接收数据的一方，比如接收智能温度计的数据显示温度的手机端。
• peripheral
  • 提供数据的一方。
  • 比如智能血压计，智能温度计。

服务(service)和特征(characteristic)

• service和characteristic是peripheral组织数据的一种方式。

• 一个peripheral可以有多个service， 每个service下可以有多个characteristic。
  

  
• characteristic下有具体的数据，比如智能灯下有两个服务：温度、亮度。亮度服务下有多个特征：当前亮度、10分钟前亮度......

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Central

使用步骤

1.导入CoreBluetooth模块

@import CoreBluetooth;

2.遵从协议

@interface BluetoothController : NSViewController

3.创建Central和Peripheral（数组）

@property (nonatomic, strong) NSMutableArray *peripheralArray;
@property (nonatomic, strong) CBCentralManager *myCentralManager;

self.myCentralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
self.peripheralArray = [NSMutableArray array];

4.查询蓝牙状态，可用的话，开始扫描

#pragma mark - CBCentralManagerDelegate methods

- (void)centralManagerDidUpdateState:(CBCentralManager *)central {
    NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:false], CBCentralManagerScanOptionAllowDuplicatesKey, nil];
    
    switch (central.state) {
        case CBCentralManagerStatePoweredOn:
            [self.myCentralManager scanForPeripheralsWithServices:nil options:dic];
            break;

        default:
            NSLog(@"Bluetooth is not working on the right state");
            break;
    }
}

5.发现Peripheral并连接

- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {
    NSLog(@"Discovered %@", peripheral.name);
    [self.peripheralArray addObject:peripheral];
    if (self.targetPeripheral != peripheral) {
        self.targetPeripheral = peripheral;
        [self.myCentralManager connectPeripheral:peripheral options:[NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:CBConnectPeripheralOptionNotifyOnDisconnectionKey]];
        peripheral.delegate = self; // 处理peripheral的事件
    }
}

这时运行程序，打印如下

Discovered MyCBServer
Discovered John’s iPhone

上面的MyCBServer是我在iphone上运行的Bluetooth Server程序中的service名称。John是我的名字。

6.连接上peripheral, 并查询服务

- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {
    NSLog(@"Connected to %@", peripheral.name);
    [peripheral discoverServices:nil]; //nil，查询所有服务
    //[peripheral discoverServices:@[[CBUUID UUIDWithString:kServiceUUID]]];//查询指定服务
}

打印：

Connected to MyCBServer

7.peripheral查到服务

打印所有服务：

#pragma mark - CBPeripheralDelegate Methods

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {
    if (error) {
        NSLog(@"error in discovering serviecs: %@", [error localizedDescription]);
        return;
    }
    
    for (CBService *service in peripheral.services) {
        NSLog(@"service's uuid : %@", service.UUID);
    }
}

打印

service's uuid : Battery
service's uuid : Current Time
service's uuid : Device Information
service's uuid : Unknown ()

上面的c5ac0853 51224856 ac70a80e 990d1c15就是iphone上运行的service UUID.

我手机上的Service和Characteristic的UUID分别为：

static NSString * const kServiceUUID = @"C5AC0853-5122-4856-AC70-A80E990D1C15";
static NSString * const kCharacteristicUUID = @"013AFE01-3E37-4E58-B6FD-DC4E67CF8F03";

上面的数字是在Mac上用uuidgen命令生成的。

UUID: Universally Unique Identifier

下面需要针对特定的service，让peripheral去查它的characteristics。
这里即是针对kServiceUUID，查它下面的特征。

#pragma mark - CBPeripheralDelegate Methods

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {
    if (error) {
        NSLog(@"error in discovering serviecs: %@", [error localizedDescription]);
        return;
    }
    
    for (CBService *service in peripheral.services) {
//        NSLog(@"service's uuid : %@", service.UUID);
        if ([service.UUID isEqual:[CBUUID UUIDWithString: kServiceUUID]]) {
            [peripheral discoverCharacteristics:[NSArray arrayWithObject:[CBUUID UUIDWithString:kCharacteristicUUID]] forService:service];
        }
    }
}

8.peripheral查到特征

打印所有特征

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error {
    if (error) {
        NSLog(@"error discovering characteristic : %@", [error localizedDescription]);
    }
    
    for (CBCharacteristic *characteristic in service.characteristics) {
        NSLog(@"characteristic uuid: %@", [characteristic UUID]);
    }
}

输出：

characteristic uuid: Unknown (<013afe01 3e374e58 b6fddc4e 67cf8f03>)

试想这个场景：智能血压计需要将某些数据即时更新给central。这里，可以给指定的特征设置Notifiy, 设置以后，peripheral的特征值更新会及时通过delegate反馈过来。

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error {
    if (error) {
        NSLog(@"error discovering characteristic : %@", [error localizedDescription]);
    }
    
    if ([service.UUID isEqual:[CBUUID UUIDWithString:kServiceUUID]]) {
        for (CBCharacteristic *characteristic in service.characteristics) {
//            NSLog(@"characteristic uuid: %@", [characteristic UUID]);
            if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:kCharacteristicUUID]]) {
                [peripheral setNotifyValue:YES forCharacteristic:characteristic];//订阅特征
            }
        }
    }
}

9.peripheral说特征值有更新

上面setNotifyValue:YES函数设置了notify。那么这个特征值有更新的话，就会通过下面的函数告诉central

- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    if (error) {
        NSLog(@"error notifying : %@", [error localizedDescription]);
        return;
    }

10.peripheral读到数据

通过下面的代理方法获取value：

- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    if (error) {
        NSLog(@"error update value : %@", [error localizedDescription]);
        return;
    }
    
    NSString *value = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];
    NSLog(@"Value: %@", value);
}

Peripheral

使用步骤

see also →_→ developer.apple.com/PeripheralRole

1.导入蓝牙模块

@import CoreBluetooth;

2.遵从CBPeripheralManagerDelegate协议

@interface ViewController : UIViewController

3.创建myPeripheralManager

@property (nonatomic, strong) CBPeripheralManager *myPeripheralManager;

self.myPeripheralManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil];

4.查询蓝牙状态, 可用的话添加服务

#pragma mark - Custom methods

- (void)addService {
    CBMutableService *service = [[CBMutableService alloc] initWithType:[CBUUID UUIDWithString:kServiceUUID] primary:YES];//primary
    CBMutableCharacteristic *characteristic = [[CBMutableCharacteristic alloc] initWithType:[CBUUID UUIDWithString:kCharacteristicUUID] properties:CBCharacteristicPropertyNotify value:nil permissions:CBAttributePermissionsReadable];
    self.myCharacteristic = characteristic;
    [service setCharacteristics:@[characteristic]];
    
    [self.myPeripheralManager addService:service];
}

#pragma mark - CBPeripheralManagerDelegate methods

- (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral {
    switch (peripheral.state) {
        case CBPeripheralManagerStatePoweredOn:
            [self addService];
            break;
            
        default:
            NSLog(@"Peripheral Manager is not working on the right state");
            break;
    }
}

5.服务添加成功，开始广告

- (void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error {
    if (error) {
        NSLog(@"Error publishing service: %@", [error localizedDescription]);
        return;
    }
    
    [self.myPeripheralManager startAdvertising:@{CBAdvertisementDataLocalNameKey:@"MyCBServer", CBAdvertisementDataServiceUUIDsKey: [CBUUID UUIDWithString:kServiceUUID]}];
}

6.广告成功

- (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral error:(NSError *)error {
    if (error) {
        NSLog(@"error advertising : %@", [error localizedDescription]);
        self.showLabel.text = [NSString stringWithFormat:@"error advertising: %@", [error localizedDescription]];
        return;
    }
    
    self.showLabel.text = @"start advertising";
    
}

7.更新特征值

添加两个button，用来改变特征值

@property (nonatomic, assign) NSInteger count;

- (IBAction)MinusButtonClicked:(id)sender {
    if ([self.myPeripheralManager state] != CBPeripheralManagerStatePoweredOn) {
        return;
    }
    --(self.count);
    NSData *data = [[NSString stringWithFormat:@"count is now %ld", (long)self.count] dataUsingEncoding:NSUTF8StringEncoding];
    [self.myPeripheralManager updateValue:data forCharacteristic:self.myCharacteristic onSubscribedCentrals:self.centrayArray];
}
- (IBAction)AddButtonClicked:(id)sender {
    if ([self.myPeripheralManager state] != CBPeripheralManagerStatePoweredOn) {
        return;
    }
    ++(self.count);
    NSData *data = [[NSString stringWithFormat:@"count is now %ld", (long)self.count] dataUsingEncoding:NSUTF8StringEncoding];
    [self.myPeripheralManager updateValue:data forCharacteristic:self.myCharacteristic onSubscribedCentrals:self.centrayArray];
}

点击button，central输出：

Value: count is now -2
Value: count is now -1
Value: count is now 0
Value: count is now 1

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资源

完整代码已上传到 →_→ github, 欢迎下载使用。