iOS开发之蓝牙通讯的介绍与使用

    一、引言

            蓝牙是设备近距离通信的一种方便手段,在iPhone引入蓝牙4.0后,设备之间的通讯变得更加简单。相关的蓝牙操作由专门的CoreBluetooth.framework进行统一管理。通过蓝牙进行通讯交互分为两方,一方为中心设备central,一方为外设peripheral,外设通过广播的方式向外发送信息,中心设备检索到外设发的广播信息,可以进行配对连接,进而进行数据交互。

    二、中心设备CBCentralManager

    CBCentralManager是管理中心设备的管理类,其中重要方法如下:

    //设置中心设备代理
    @property(assign, nonatomic, nullable) id<CBCentralManagerDelegate> delegate;
    //中心设备当前状态
    @property(readonly) CBCentralManagerState state;
    //中心设备是否正在扫描
    @property(readonly) BOOL isScanning NS_AVAILABLE(NA, 9_0);

    其中state是一个枚举,有关蓝牙是否可用的状态如下:

    typedef NS_ENUM(NSInteger, CBCentralManagerState) {
            //状态未知
        CBCentralManagerStateUnknown = 0,
        //连接断开 即将重置
        CBCentralManagerStateResetting,
        //该平台不支持蓝牙
        CBCentralManagerStateUnsupported,
        //未授权蓝牙使用 hovertree.com
        CBCentralManagerStateUnauthorized,
        //蓝牙关闭
        CBCentralManagerStatePoweredOff,
        //蓝牙正常开启
        CBCentralManagerStatePoweredOn,
    };
    
    

    下面这些方法用于初始化管理中心:

    //初始化方法
    //设置的代理需要遵守CBCentralManagerDelegate协议
    //queue可以设置蓝牙扫描的线程 传入nil则为在主线程中进行
    - (instancetype)initWithDelegate:(nullable id<CBCentralManagerDelegate>)delegate
                               queue:(nullable dispatch_queue_t)queue;
    //此方法同上 在options字典中用于进行一些管理中心的初始化属性设置
    //字典中支持的键值如下 http://www.cnblogs.com/roucheng/
    /*
    NSString * const CBCentralManagerOptionShowPowerAlertKey 对应一个NSNumber类型的bool值,用于设置是否在关闭蓝牙时弹出用户提示
    NSString * const CBCentralManagerOptionRestoreIdentifierKey 对应一个NSString对象,设置管理中心的标识符ID
    */
    - (instancetype)initWithDelegate:(nullable id<CBCentralManagerDelegate>)delegate
                               queue:(nullable dispatch_queue_t)queue
                             options:(nullable NSDictionary<NSString *, id> *)options;
    
    
    
    //根据获取所有已知设备
    - (NSArray<CBPeripheral *> *)retrievePeripheralsWithIdentifiers:(NSArray<NSUUID *> *)identifiers;
    //根据服务id获取所有连接的设备 hovertree.com
    - (NSArray<CBPeripheral *> *)retrieveConnectedPeripheralsWithServices:(NSArray<CBUUID *> *)serviceUUIDs;

    在初始化管理中心完成后,会回调代理中的如下方法,我们必须实现如下方法:

    //这个方法中可以获取到管理中心的状态
    - (void)centralManagerDidUpdateState:(CBCentralManager *)central;

    如果上面方法中管理中心状态为蓝牙可用,可以通过下面方法开启扫描外设:

    //serviceUUIDs用于扫描一个特点ID的外设 options用于设置一些扫描属性 键值如下
    /*
    //是否允许重复扫描 对应NSNumber的bool值,默认为NO,会自动去重
    NSString *const CBCentralManagerScanOptionAllowDuplicatesKey;
    //要扫描的设备UUID 数组 对应NSArray hovertree.com
    NSString *const CBCentralManagerScanOptionSolicitedServiceUUIDsKey;
    */
    - (void)scanForPeripheralsWithServices:(nullable NSArray<CBUUID *> *)serviceUUIDs options:(nullable NSDictionary<NSString *, id> *)options;
    
    
    
    //停止扫描外设
    - (void)stopScan;

    扫描的结果会在如下代理方法中回掉:

    //peripheral 扫描到的外设
    //advertisementData是外设发送的广播数据
    //RSSI 是信号强度 http://www.cnblogs.com/roucheng/
    - (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary<NSString *, id> *)advertisementData RSSI:(NSNumber *)RSSI;

    扫描到外设后,通过下面方法可以连接一个外设:

    /*
    options中可以设置一些连接设备的初始属性键值如下
    //对应NSNumber的bool值,设置当外设连接后是否弹出一个警告
    NSString *const CBConnectPeripheralOptionNotifyOnConnectionKey;
    //对应NSNumber的bool值,设置当外设断开连接后是否弹出一个警告
    NSString *const CBConnectPeripheralOptionNotifyOnDisconnectionKey;
    //对应NSNumber的bool值,设置当外设暂停连接后是否弹出一个警告 http://www.cnblogs.com/roucheng/
    NSString *const CBConnectPeripheralOptionNotifyOnNotificationKey;
    */
    - (void)connectPeripheral:(CBPeripheral *)peripheral options:(nullable NSDictionary<NSString *, id> *)options;
    //取消一个外设的连接
    - (void)cancelPeripheralConnection:(CBPeripheral *)peripheral;
    
    
    

    调用过连接外设的方法后,会回掉如下代理方法:

    //连接外设成功
    - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral;
    //连接外设失败
    - (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(nullable NSError *)error;
    //断开外设连接
    - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(nullable NSError *)error;

    当管理中心恢复时会调用如下代理:

     1 //dict中会传入如下键值对 hovertree.com
     2 /*
     3 //恢复连接的外设数组
     4 NSString *const CBCentralManagerRestoredStatePeripheralsKey;
     5 //恢复连接的服务UUID数组
     6 NSString *const CBCentralManagerRestoredStateScanServicesKey;
     7 //恢复连接的外设扫描属性字典数组
     8 NSString *const CBCentralManagerRestoredStateScanOptionsKey;
     9 */
    10 - (void)centralManager:(CBCentralManager *)central willRestoreState:(NSDictionary<NSString *, id> *)dict;
    
    
    

    三、外设CBPeripheralManager

    从上面我们知道,中心设备是用来扫描周围的外设,两台设备的通讯中,必须有一个充当中心设备,一个充当外设,外设是由CBPeripheralManager进行管理,主要方法如下:

     1 //设置外设管理中心代理
     2 @property(assign, nonatomic, nullable) id<CBPeripheralManagerDelegate> delegate;
     3 //外设状态 枚举如中心设备
     4 @property(readonly) CBPeripheralManagerState state;
     5 //是否正在发送广播
     6 @property(readonly) BOOL isAdvertising;
     7 //用户的授权状态
     8 + (CBPeripheralManagerAuthorizationStatus)authorizationStatus;
     9 //初始化并设置代理 参数的具体含义与中心设备管理中心
    10 - (instancetype)initWithDelegate:(nullable id<CBPeripheralManagerDelegate>)delegate
    11                            queue:(nullable dispatch_queue_t);
    12 - (instancetype)initWithDelegate:(nullable id<CBPeripheralManagerDelegate>)delegate
    13                            queue:(nullable dispatch_queue_t)queue
    14                          options:(nullable NSDictionary<NSString *, id> *)options;
    15 //开始发送广播 hovertree.com  何问起
    16 //advertisementData中可以发送的数据有约定 如下
    17 /*
    18 对应设置NSString类型的广播名
    19 NSString *const CBAdvertisementDataLocalNameKey;
    20 外设制造商的NSData数据
    21 NSString *const CBAdvertisementDataManufacturerDataKey;
    22 外设制造商的CBUUID数据
    23 NSString *const CBAdvertisementDataServiceDataKey;
    24 服务的UUID与其对应的服务数据字典数组
    25 NSString *const CBAdvertisementDataServiceUUIDsKey;
    26 附加服务的UUID数组
    27 NSString *const CBAdvertisementDataOverflowServiceUUIDsKey;
    28 外设的发送功率 NSNumber类型
    29 NSString *const CBAdvertisementDataTxPowerLevelKey;
    30 外设是否可以连接
    31 NSString *const CBAdvertisementDataIsConnectable;
    32 服务的UUID数组
    33 NSString *const CBAdvertisementDataSolicitedServiceUUIDsKey;
    34 */
    35 - (void)startAdvertising:(nullable NSDictionary<NSString *, id> *)advertisementData;
    36 //停止发送广播
    37 - (void)stopAdvertising;
    38 //设置一个连接的具体central设备的延时 枚举如下
    39 /*
    40 typedef NS_ENUM(NSInteger, CBPeripheralManagerConnectionLatency) {
    41     CBPeripheralManagerConnectionLatencyLow = 0,
    42     CBPeripheralManagerConnectionLatencyMedium,
    43     CBPeripheralManagerConnectionLatencyHigh
    44 } NS_ENUM_AVAILABLE(NA, 6_0);
    45 */
    46 - (void)setDesiredConnectionLatency:(CBPeripheralManagerConnectionLatency)latency forCentral:(CBCentral *)central;
    47 //添加一个服务 http://www.cnblogs.com/roucheng/
    48 - (void)addService:(CBMutableService *)service;
    49 //移除一个服务
    50 - (void)removeService:(CBMutableService *)service;
    51 //移除所有服务
    52 - (void)removeAllServices;
    53 //响应中心设备的读写请求
    54 - (void)respondToRequest:(CBATTRequest *)request withResult:(CBATTError)result;
    55 //更新一个连接中心设备的订阅特征值
    56 - (BOOL)updateValue:(NSData *)value forCharacteristic:(CBMutableCharacteristic *)characteristic onSubscribedCentrals:(nullable NSArray<CBCentral *> *)centrals;
    
    

    外设代理的相关方法如下:

     1 //这个方法是必须实现的 状态可用后可以发送广播
     2 - (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral;
     3 //连接回复时调用的方法 和centralManager类似
     4 - (void)peripheralManager:(CBPeripheralManager *)peripheral willRestoreState:(NSDictionary<NSString *, id> *)dict;
     5 //开始发送广播时调用的方法
     6 - (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral error:(nullable NSError *)error;
     7 //添加服务调用的回调
     8 - (void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(nullable NSError *)error;
     9 //当一个central设备订阅一个特征值时调用的方法
    10 - (void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didSubscribeToCharacteristic:(CBCharacteristic *)characteristic;
    11 //取消订阅一个特征值时调用的方法
    12 - (void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didUnsubscribeFromCharacteristic:(CBCharacteristic *)characteristic;
    13 //收到读请求时触发的方法 何问起 hovertree.com
    14 - (void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveReadRequest:(CBATTRequest *)request;
    15 //收到写请求时触发的方法
    16 - (void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveWriteRequests:(NSArray<CBATTRequest *> *)requests;
    17 //外设准备更新特征值时调用的方法
    18 - (void)peripheralManagerIsReadyToUpdateSubscribers:(CBPeripheralManager *)peripheral;
    
    

    四、中心设备与外设对象CBCentral与CBPeripheral

    上面介绍了中心设备管理类与外设管理类,这些类用于将设备连接建立起来,器具的数据交换的服务和一些信息则是在对应的设备对象中。

    1、中心设备 CBCentral属性与方法

    //设备UUID
    @property(readonly, nonatomic) NSUUID *identifier;
    //中心设备最大接收的数据长度
    @property(readonly, nonatomic) NSUInteger maximumUpdateValueLength;

    2、外设CAPeripheral属性与方法

    外设对象要比中心对象复杂的多,当centralManager连接到外设后,需要通过外设对象的代理方法进行数据交互,其中主要方法属性如下:

     1 //设置代理
     2 @property(assign, nonatomic, nullable) id<CBPeripheralDelegate> delegate;
     3 //外设name
     4 @property(retain, readonly, nullable) NSString *name;
     5 //信号强度 http://www.cnblogs.com/roucheng/
     6 @property(retain, readonly, nullable) NSNumber *RSSI NS_DEPRECATED(NA, NA, 5_0, 8_0);
     7 //外设状态
     8 /*
     9 typedef NS_ENUM(NSInteger, CBPeripheralState) {
    10     CBPeripheralStateDisconnected = 0,//未连接
    11     CBPeripheralStateConnecting,//正在链接
    12     CBPeripheralStateConnected,//已经连接
    13     CBPeripheralStateDisconnecting NS_AVAILABLE(NA, 9_0),//正在断开连接
    14 } NS_AVAILABLE(NA, 7_0);
    15 */
    16 @property(readonly) CBPeripheralState state;
    17 //所有的服务数组
    18 @property(retain, readonly, nullable) NSArray<CBService *> *services;
    19 //获取当前信号强度
    20 - (void)readRSSI;
    21 //根据服务UUID寻找服务对象
    22 - (void)discoverServices:(nullable NSArray<CBUUID *> *)serviceUUIDs;
    23 //在服务对象UUID数组中寻找特定服务
    24 - (void)discoverIncludedServices:(nullable NSArray<CBUUID *> *)includedServiceUUIDs forService:(CBService *)service;
    25 //在一个服务中寻找特征值
    26 - (void)discoverCharacteristics:(nullable NSArray<CBUUID *> *)characteristicUUIDs forService:(CBService *)service;
    27 //从一个特征中读取数据
    28 - (void)readValueForCharacteristic:(CBCharacteristic *)characteristic;
    29 //写数据的最大长度 hovertree.com  何问起
    30 //type枚举如下
    31 /*
    32 typedef NS_ENUM(NSInteger, CBCharacteristicWriteType) {
    33     CBCharacteristicWriteWithResponse = 0,//写数据并且接收成功与否回执
    34     CBCharacteristicWriteWithoutResponse,//写数据不接收回执
    35 };
    36 */
    37 - (NSUInteger)maximumWriteValueLengthForType:(CBCharacteristicWriteType)type NS_AVAILABLE(NA, 9_0);
    38 //向某个特征中写数据
    39 - (void)writeValue:(NSData *)data forCharacteristic:(CBCharacteristic *)characteristic type:(CBCharacteristicWriteType)type;
    40 //为制定的特征值设置监听通知
    41 - (void)setNotifyValue:(BOOL)enabled forCharacteristic:(CBCharacteristic *)characteristic;
    42 //寻找特征值的描述
    43 - (void)discoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic;
    44 //读取特征的描述值
    45 - (void)readValueForDescriptor:(CBDescriptor *)descriptor;
    46 //写特征的描述值
    47 - (void)writeValue:(NSData *)data forDescriptor:(CBDescriptor *)descriptor;

    View Code

    外设的代理方法如下:

     1 //外设名称更改时回调的方法
     2 - (void)peripheralDidUpdateName:(CBPeripheral *)peripheral NS_AVAILABLE(NA, 6_0);
     3 //外设服务变化时回调的方法
     4 - (void)peripheral:(CBPeripheral *)peripheral didModifyServices:(NSArray<CBService *> *)invalidatedServices NS_AVAILABLE(NA, 7_0);
     5 //信号强度改变时调用的方法
     6 - (void)peripheralDidUpdateRSSI:(CBPeripheral *)peripheral error:(nullable NSError *)error NS_DEPRECATED(NA, NA, 5_0, 8_0);
     7 //读取信号强度回调的方法 柯乐义 keleyi.com
     8 - (void)peripheral:(CBPeripheral *)peripheral didReadRSSI:(NSNumber *)RSSI error:(nullable NSError *)error NS_AVAILABLE(NA, 8_0);
     9 //发现服务时调用的方法
    10 - (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(nullable NSError *)error;
    11 //在服务中发现子服务回调的方法
    12 - (void)peripheral:(CBPeripheral *)peripheral didDiscoverIncludedServicesForService:(CBService *)service error:(nullable NSError *)error;
    13 //发现服务的特征值后回调的方法
    14 - (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(nullable NSError *)error;
    15 //特征值更新时回调的方法
    16 - (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(nullable NSError *)error;
    17 //向特征值写数据时回调的方法
    18  - (void)peripheral:(CBPeripheral *)peripheral didWriteValueForCharacteristic:(CBCharacteristic *)characteristic error:(nullable NSError *)error;
    19  //特征值的通知设置改变时触发的方法
    20  - (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(nullable NSError *)error;
    21  //发现特征值的描述信息触发的方法
    22  - (void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic error:(nullable NSError *)error;
    23  //特征的描述值更新时触发的方法
    24  - (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForDescriptor:(CBDescriptor *)descriptor error:(nullable NSError *)error;
    25  //写描述信息时触发的方法
    26  - (void)peripheral:(CBPeripheral *)peripheral didWriteValueForDescriptor:(CBDescriptor *)descriptor error:(nullable NSError *)error;

    View Code

    五、服务对象CBService

    服务对象是用来管理外设提供的一些数据服务的,其中属性如下:

    //对应的外设
    @property(assign, readonly, nonatomic) CBPeripheral *peripheral;
    //是否是初等服务
    @property(readonly, nonatomic) BOOL isPrimary;
    //包含的自服务 http://www.cnblogs.com/roucheng/
    @property(retain, readonly, nullable) NSArray<CBService *> *includedServices;
    //服务中的特征值
    @property(retain, readonly, nullable) NSArray<CBCharacteristic *> *characteristics;
    
    

    六、服务的特征值CBCharacteristic

    通过绑定服务中的特征值来进行数据的读写操作,其中属性如下:

    //对应的服务对象
    @property(assign, readonly, nonatomic) CBService *service;
    //特征值的属性 枚举如下
    /*
    typedef NS_OPTIONS(NSUInteger, CBCharacteristicProperties) {
        CBCharacteristicPropertyBroadcast,//允许广播特征
        CBCharacteristicPropertyRead,//可读属性
        CBCharacteristicPropertyWriteWithoutResponse,//可写并且接收回执
        CBCharacteristicPropertyWrite,//可写属性
        CBCharacteristicPropertyNotify,//可通知属性
        CBCharacteristicPropertyIndicate,//可展现的特征值
        CBCharacteristicPropertyAuthenticatedSignedWrites,//允许签名的特征值写入
        CBCharacteristicPropertyExtendedProperties,
        CBCharacteristicPropertyNotifyEncryptionRequired,
        CBCharacteristicPropertyIndicateEncryptionRequired
    };
    */
    @property(readonly, nonatomic) CBCharacteristicProperties properties;
    //特征值的数据 http://www.cnblogs.com/roucheng/
    @property(retain, readonly, nullable) NSData *value;
    //特征值的描述
    @property(retain, readonly, nullable) NSArray<CBDescriptor *> *descriptors;
    //是否是当前广播的特征
    @property(readonly) BOOL isBroadcasted;
    //是否是正在通知的特征
    @property(readonly) BOOL isNotifying;
    
    
    

    七、读写请求对象CBATTRequest

    服务对象是外设向中心设备提供的相关数据服务,获取到相应服务后,中心设备可以进行读写请求,读写对象属性如下:

    //对应的中心设备
    @property(readonly, nonatomic) CBCentral *central;
    //对应的特征值
    @property(readonly, nonatomic) CBCharacteristic *characteristic;
    //读写数据值
    @property(readwrite, copy, nullable) NSData *value;
    本博客所有文章如无特别注明均为原创。
    复制或转载请以超链接形式注明转自koala,原文地址《iOS开发之蓝牙通讯的介绍与使用
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