iOS【蓝牙开发】实践一 数据接发

说明：这次实践的主要目的是简单掌握蓝牙的一些基本信息，实现数据的接发，中心与外设互相发送数据，大数据分块发送。最后为项目链接。

中心1.png

外设2.png

蓝牙基础（常见缩写）
MFI： 专们为苹果设备制作的设备，详见:关于MFi认证你所必须要知道的事情；
BLE：蓝牙4.0设备因为低耗电，所以也叫做BLE；
MFI：开发使用ExternalAccessory 框架；
4.0 BLE：开发使用CoreBluetooth 框架；

Peripheral：外设，被连接的设备为Peripheral；
Central：中心,发起连接的是Central；
Service：服务，每个外设会有很多服务，每个服务中包含很多字段，这些字段的权限一般分为 读read，写write，通知notiy几种;
Characteristic：一个服务下面也可以存在多个特征，特征可以理解成具体实现功能的窗口，一般特征都会有value，也就是特征值，特征是与外界交互的最小单位；
Description：每个特征可以对应一个或多个Description用户描述characteristic的信息或属性；
UUID：可以理解成蓝牙上的唯一标识符，为了区分不同的服务和特征，或者给服务和特征取名字，我们就用UUID来代表服务和特征；


快速生成UUID:
打开Mac OS X的Terminal.app，用uuidgen命令生成一个128bit的UUID

//服务id
#define TRANSFER_SERVICE_UUID  @"0FB51F75-C9D5-45DC-BA61-065BD4A5E3E8"
//特征id
#define TRANSFER_CHARACTERISTIC_UP_UUID @"B678C8E2-9B1A-4952-A320-EF6D42F0831A"

-------------------------------
蓝牙中心模式流程：
1. 建立中心角色
2. 扫描外设（discover）
3. 连接外设(connect)
4. 扫描外设中的服务和特征(discover)
5. 与外设做数据交互(explore and interact)
6. 订阅Characteristic的通知
7. 断开连接(disconnect)

---

中心：首先要导入蓝牙库
#import 

遵守协议


1. 建立中心角色 创建CBCentralManager对象
_centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];

2. 扫描外设（discover）
//查看设备是否支持 ，若支持则扫描
-(void)centralManagerDidUpdateState:(CBCentralManager *)central{
    NSArray *uuidArray = [NSArray arrayWithObjects:[CBUUID UUIDWithString:TRANSFER_SERVICE_UUID],nil];
    NSDictionary *optionsDic = [[NSDictionary alloc] initWithObjectsAndKeys:[NSNumber numberWithBool:NO],CBCentralManagerScanOptionAllowDuplicatesKey, nil];
    [_centralManager scanForPeripheralsWithServices:uuidArray options:optionsDic];
}

3. 连接外设(connect)
-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {

    if (_discoveredPeripheral != peripheral) {
        _discoveredPeripheral = peripheral;
        [_centralManager connectPeripheral:peripheral options:nil];
    }
}

4. 扫描外设中的服务和特征(discover)
//当连接成功后，系统会通过回调函数告诉我们，然后我们就在这个回调里去扫描设备下所有的服务和特征
-(void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {

    peripheral.delegate = self;
    //指定服务 
    [peripheral discoverServices:[[NSArray alloc] initWithObjects:[CBUUID UUIDWithString:TRANSFER_SERVICE_UUID], nil]];
    //[peripheral discoverServices:nil];
}

-4.1 获取外设的services  6. 订阅Characteristic的通知
-(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{

    //处理我们需要的特征
    for (int i=0; i

---

外设：首先要导入蓝牙库
#import 

遵守协议


1. 建立外设角色 创建CBPeripheralManager对象
_peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil];

2. 本地Peripheral设置服务,特性,描述，权限等等
//1 查看设备是否支持 ，若支持则创建 服务和特征
-(void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral{

    //一组特征值
    _upCharacteristic = [[CBMutableCharacteristic alloc] initWithType:[CBUUID UUIDWithString:TRANSFER_CHARACTERISTIC_UP_UUID] properties:CBCharacteristicPropertyNotify | CBCharacteristicPropertyRead | CBCharacteristicPropertyWrite | CBCharacteristicPropertyWriteWithoutResponse value:nil permissions:CBAttributePermissionsReadable | CBAttributePermissionsWriteable];

    //一个服务中添加多个特征值
    transferService = [[CBMutableService alloc] initWithType:[CBUUID UUIDWithString:TRANSFER_SERVICE_UUID] primary:YES];
    NSArray *characters = [[NSArray alloc] initWithObjects:_upCharacteristic, nil];
    [transferService setCharacteristics:characters];

    // 2 添加一个服务
    [self.peripheralManager addService:transferService];  
}

3. Peripheral发送广告
// 3 会监听didAddService
-(void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error{
    NSLog(@"添加服务");
    if (error != nil) {
        NSLog(@"添加服务失败： %@",error.localizedDescription);
    } else {        
        // 开始广播
        [self.peripheralManager startAdvertising:@{ CBAdvertisementDataLocalNameKey : @"Service_name", CBAdvertisementDataServiceUUIDsKey :@[[CBUUID UUIDWithString:TRANSFER_SERVICE_UUID]] }];
    }
}

4. 设置处理订阅、取消订阅、
//当中央端连接上了此设备并订阅了特征时会回调 didSubscribeToCharacteristic
-(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didSubscribeToCharacteristic:(CBCharacteristic *)characteristic {
NSLog(@"中心已经预定了特征 --- %@",characteristic);
}

//当中央端取消订阅时会调用didUnsubscribeFromCharacteristic
-(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didUnsubscribeFromCharacteristic:(CBCharacteristic *)characteristic {
NSLog(@"中心没有从特征预定 -- %@",characteristic);
}

 4. 读characteristic、写characteristic的委托方法
//当接收到中央端读的请求时会调用didReceiveReadRequest
- (void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveReadRequest:(CBATTRequest *)request {
    if (request.characteristic.properties & CBCharacteristicPropertyRead) {
        NSData *data = request.characteristic.value;        
        [request setValue:data];
        [self.peripheralManager respondToRequest:request withResult:CBATTErrorSuccess];
    } else {
        [self.peripheralManager respondToRequest:request withResult:CBATTErrorReadNotPermitted];
    }
}

//当接收到中央端写的请求时会调用didReceiveWriteRequest
- (void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveWriteRequests:(NSArray *)requests {
CBATTRequest *request = requests[0];
    if (request.characteristic.properties & CBCharacteristicPropertyWrite) {
        CBMutableCharacteristic *c = (CBMutableCharacteristic *)request.characteristic;
        c.value = request.value;
        NSData *data = c.value;
       [self.peripheralManager respondToRequest:request withResult:CBATTErrorSuccess];
    } else {
        [self.peripheralManager respondToRequest:request withResult:CBATTErrorWriteNotPermitted];
    }
}

4. 往中心发送数据
- (BOOL)updateValue:(NSData *)value characteristic:(CBMutableCharacteristic *)characteristic {

    if (value && characteristic) {
       return [self.peripheralManager updateValue:value forCharacteristic:characteristic onSubscribedCentrals:nil];
    }
    return NO;
}

项目Demo：蓝牙外设 、蓝牙中心