IOS 蓝牙---广州鼎瀛APP开发专家

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CoreBluetooth介绍
CoreBluetooth框架的核心其实是两个东西，peripheral和central, 可以理解成外设和中心。对应他们分别有一组相关的API和类，如下图所示:


如果你要编程的设备是central那么你大部分用到，反之亦然。在我们这个示例中，金融刷卡器是peripheral,我们的iphone手机是central,所以我将大部分使用上图中左边部分的类。使用peripheral编程的例子也有很多，比如像用一个ipad和一个iphone通讯，ipad可以认为是central，iphone端是peripheral,这种情况下在iphone端就要使用上图右边部分的类来开发了。

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四 服务和特征

有个概念有必要先说明一下。什么是服务和特征呢(service and characteristic)?

每个蓝牙4.0的设备都是通过服务和特征来展示自己的，一个设备必然包含一个或多个服务，每个服务下面又包含若干个特征。特征是与外界交互的最小单位。比如说，一台蓝牙4.0设备，用特征A来描述自己的出厂信息，用特征B来与收发数据等。

服务和特征都是用UUID来唯一标识的，UUID的概念如果不清楚请自行google,国际蓝牙组织为一些很典型的设备(比如测量心跳和血压的设备)规定了标准的service UUID(特征的UUID比较多，这里就不列举了),如下:

[objc] view plaincopyprint?

• #define      BLE_UUID_ALERT_NOTIFICATION_SERVICE   0x1811
• #define     BLE_UUID_BATTERY_SERVICE   0x180F
• #define     BLE_UUID_BLOOD_PRESSURE_SERVICE   0x1810
• #define     BLE_UUID_CURRENT_TIME_SERVICE   0x1805
• #define     BLE_UUID_CYCLING_SPEED_AND_CADENCE   0x1816
• #define     BLE_UUID_DEVICE_INFORMATION_SERVICE   0x180A
• #define     BLE_UUID_GLUCOSE_SERVICE   0x1808
• #define     BLE_UUID_HEALTH_THERMOMETER_SERVICE   0x1809
• #define     BLE_UUID_HEART_RATE_SERVICE   0x180D
• #define     BLE_UUID_HUMAN_INTERFACE_DEVICE_SERVICE   0x1812
• #define     BLE_UUID_IMMEDIATE_ALERT_SERVICE   0x1802
• #define     BLE_UUID_LINK_LOSS_SERVICE   0x1803
• #define     BLE_UUID_NEXT_DST_CHANGE_SERVICE   0x1807
• #define     BLE_UUID_PHONE_ALERT_STATUS_SERVICE   0x180E
• #define     BLE_UUID_REFERENCE_TIME_UPDATE_SERVICE   0x1806
• #define     BLE_UUID_RUNNING_SPEED_AND_CADENCE   0x1814
• #define     BLE_UUID_SCAN_PARAMETERS_SERVICE   0x1813
• #define     BLE_UUID_TX_POWER_SERVICE   0x1804
• #define     BLE_UUID_CGM_SERVICE   0x181A
  

#define      BLE_UUID_ALERT_NOTIFICATION_SERVICE   0x1811 #define     BLE_UUID_BATTERY_SERVICE   0x180F #define     BLE_UUID_BLOOD_PRESSURE_SERVICE   0x1810 #define     BLE_UUID_CURRENT_TIME_SERVICE   0x1805 #define     BLE_UUID_CYCLING_SPEED_AND_CADENCE   0x1816 #define     BLE_UUID_DEVICE_INFORMATION_SERVICE   0x180A #define     BLE_UUID_GLUCOSE_SERVICE   0x1808 #define     BLE_UUID_HEALTH_THERMOMETER_SERVICE   0x1809 #define     BLE_UUID_HEART_RATE_SERVICE   0x180D #define     BLE_UUID_HUMAN_INTERFACE_DEVICE_SERVICE   0x1812 #define     BLE_UUID_IMMEDIATE_ALERT_SERVICE   0x1802 #define     BLE_UUID_LINK_LOSS_SERVICE   0x1803 #define     BLE_UUID_NEXT_DST_CHANGE_SERVICE   0x1807 #define     BLE_UUID_PHONE_ALERT_STATUS_SERVICE   0x180E #define     BLE_UUID_REFERENCE_TIME_UPDATE_SERVICE   0x1806 #define     BLE_UUID_RUNNING_SPEED_AND_CADENCE   0x1814 #define     BLE_UUID_SCAN_PARAMETERS_SERVICE   0x1813 #define     BLE_UUID_TX_POWER_SERVICE   0x1804 #define     BLE_UUID_CGM_SERVICE   0x181A


当然还有很多设备并不在这个标准列表里，比如我用的这个金融刷卡器。蓝牙设备硬件厂商通常都会提供他们的设备里面各个服务(service)和特征(characteristics)的功能，比如哪些是用来交互(读写)，哪些可获取模块信息(只读)等。


五 实现细节

作为一个中心要实现完整的通讯，一般要经过这样几个步骤：

建立中心角色—扫描外设（discover）—连接外设(connect)—扫描外设中的服务和特征(discover)—与外设做数据交互(explore and interact)—断开连接(disconnect)。

1建立中心角色

首先在我自己类的头文件中要包含CoreBluetooth的头文件，并继承两个协议<CBCentralManagerDelegate,CBPeripheralDelegate>，代码如下:

[objc] view plaincopyprint?

• #import <CoreBluetooth/CoreBluetooth.h>
• CBCentralManager *manager;
• manager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
  

#import <CoreBluetooth/CoreBluetooth.h>CBCentralManager *manager;manager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];


2扫描外设（discover）

代码如下:

[objc] view plaincopyprint?

• [manager scanForPeripheralsWithServices:nil optionsptions];
  

[manager scanForPeripheralsWithServices:nil optionsptions];


这个参数应该也是可以指定特定的peripheral的UUID,那么理论上这个central只会discover这个特定的设备，但是我实际测试发现，如果用特定的UUID传参根本找不到任何设备，我用的代码如下:

[objc] view plaincopyprint?

• NSArray *uuidArray = [NSArray arrayWithObjects:[CBUUID UUIDWithString"1800"],[CBUUID UUIDWithString"180A"],
• [CBUUID UUIDWithString"1CB2D155-33A0-EC21-6011-CD4B50710777"],[CBUUID UUIDWithString"6765D311-DD4C-9C14-74E1-A431BBFD0652"],nil];
• [manager scanForPeripheralsWithServices:uuidArray optionsptions];
  

NSArray *uuidArray = [NSArray arrayWithObjects:[CBUUID UUIDWithString"1800"],[CBUUID UUIDWithString"180A"],[CBUUID UUIDWithString"1CB2D155-33A0-EC21-6011-CD4B50710777"],[CBUUID UUIDWithString"6765D311-DD4C-9C14-74E1-A431BBFD0652"],nil];     [manager scanForPeripheralsWithServices:uuidArray optionsptions];  
目前不清楚原因，怀疑和设备本身在的广播包有关。

3连接外设(connect)
当扫描到4.0的设备后，系统会通过回调函数告诉我们设备的信息，然后我们就可以连接相应的设备，代码如下:

[objc] view plaincopyprint?

• - (void)centralManagerCBCentralManager *)central didDiscoverPeripheralCBPeripheral *)peripheral advertisementDataNSDictionary *)advertisementData RSSINSNumber *)RSSI
• {
•     if(![_dicoveredPeripherals containsObject:peripheral])
•         [_dicoveredPeripherals addObject:peripheral];
•     NSLog(@"dicoveredPeripherals:%@", _dicoveredPeripherals);
• }
  

- (void)centralManagerCBCentralManager *)central didDiscoverPeripheralCBPeripheral *)peripheral advertisementDataNSDictionary *)advertisementData RSSINSNumber *)RSSI{    if(![_dicoveredPeripherals containsObject:peripheral])        [_dicoveredPeripherals addObject:peripheral];        NSLog(@"dicoveredPeripherals:%@", _dicoveredPeripherals);}



[objc] view plaincopyprint?

• //连接指定的设备
• -(BOOL)connectCBPeripheral *)peripheral
• {
•     NSLog(@"connect start");
•     _testPeripheral = nil;
•     [manager connectPeripheral:peripheral
•                       options:[NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:CBConnectPeripheralOptionNotifyOnDisconnectionKey]];
•     //开一个定时器监控连接超时的情况
•     connectTimer = [NSTimer scheduledTimerWithTimeInterval:5.0f target:self selectorselector(connectTimeout userInfo:peripheral repeats:NO];
•     return (YES);
• }
  

//连接指定的设备-(BOOL)connectCBPeripheral *)peripheral{    NSLog(@"connect start");    _testPeripheral = nil;        [manager connectPeripheral:peripheral                       options:[NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:CBConnectPeripheralOptionNotifyOnDisconnectionKey]];        //开一个定时器监控连接超时的情况    connectTimer = [NSTimer scheduledTimerWithTimeInterval:5.0f target:self selectorselector(connectTimeout userInfo:peripheral repeats:NO];    return (YES);}


4扫描外设中的服务和特征(discover)
同样的，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，代码如下:

[objc] view plaincopyprint?

• - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral
• {
•     [connectTimer invalidate];//停止时钟
•     NSLog(@"Did connect to peripheral: %@", peripheral);
•     _testPeripheral = peripheral;
•     [peripheral setDelegate:self];
•     [peripheral discoverServices:nil];
• }
  

- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{    [connectTimer invalidate];//停止时钟        NSLog(@"Did connect to peripheral: %@", peripheral);    _testPeripheral = peripheral;        [peripheral setDelegate:self];    [peripheral discoverServices:nil];        }

一个设备里的服务和特征往往比较多，大部分情况下我们只是关心其中几个，所以一般会在发现服务和特征的回调里去匹配我们关心那些，比如下面的代码:

[objc] view plaincopyprint?

• - (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
• {
•     NSLog(@"didDiscoverServices");
•     if (error)
•     {
•         NSLog(@"Discovered services for %@ with error: %@", peripheral.name, [error localizedDescription]);
•         if ([self.delegate respondsToSelector:@selector(DidNotifyFailConnectService:withPeripheral:error])
•             [self.delegate DidNotifyFailConnectService:nil withPeripheral:nil error:nil];
•         return;
•     }
•     for (CBService *service in peripheral.services)
•     {
•         if ([service.UUID isEqual:[CBUUID UUIDWithString:UUIDSTR_ISSC_PROPRIETARY_SERVICE]])
•         {
•             NSLog(@"Service found with UUID: %@", service.UUID);
•             [peripheral discoverCharacteristics:nil forService:service];
•             isVPOS3356 = YES;
•             break;
•         }
•     }
• }
  

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{        NSLog(@"didDiscoverServices");        if (error)    {        NSLog(@"Discovered services for %@ with error: %@", peripheral.name, [error localizedDescription]);                if ([self.delegate respondsToSelector:@selector(DidNotifyFailConnectService:withPeripheral:error])            [self.delegate DidNotifyFailConnectService:nil withPeripheral:nil error:nil];                return;    }        for (CBService *service in peripheral.services)    {                if ([service.UUID isEqual:[CBUUID UUIDWithString:UUIDSTR_ISSC_PROPRIETARY_SERVICE]])        {            NSLog(@"Service found with UUID: %@", service.UUID);            [peripheral discoverCharacteristics:nil forService:service];            isVPOS3356 = YES;            break;        }                    }}
[objc] view plaincopyprint?

• - (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
• {
•     if (error)
•     {
•         NSLog(@"Discovered characteristics for %@ with error: %@", service.UUID, [error localizedDescription]);
•         if ([self.delegate respondsToSelector:@selector(DidNotifyFailConnectChar:withPeripheral:error])
•             [self.delegate DidNotifyFailConnectChar:nil withPeripheral:nil error:nil];
•         return;
•     }
•     for (CBCharacteristic *characteristic in service.characteristics)
•     {
•         if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:UUIDSTR_ISSC_TRANS_TX]])
•         {
•             NSLog(@"Discovered read characteristics:%@ for service: %@", characteristic.UUID, service.UUID);
•             _readCharacteristic = characteristic;//保存读的特征
•             if ([self.delegate respondsToSelector:@selector(DidFoundReadChar])
•                 [self.delegate DidFoundReadChar:characteristic];
•             break;
•         }
•     }
•     for (CBCharacteristic * characteristic in service.characteristics)
•     {
•         if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:UUIDSTR_ISSC_TRANS_RX]])
•         {
•             NSLog(@"Discovered write characteristics:%@ for service: %@", characteristic.UUID, service.UUID);
•             _writeCharacteristic = characteristic;//保存写的特征
•             if ([self.delegate respondsToSelector:@selector(DidFoundWriteChar])
•                 [self.delegate DidFoundWriteChar:characteristic];
•             break;
•         }
•     }
•     if ([self.delegate respondsToSelector:@selector(DidFoundCharacteristic:withPeripheral:error])
•         [self.delegate DidFoundCharacteristic:nil withPeripheral:nil error:nil];
• }
  

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error {        if (error)     {        NSLog(@"Discovered characteristics for %@ with error: %@", service.UUID, [error localizedDescription]);                if ([self.delegate respondsToSelector:@selector(DidNotifyFailConnectChar:withPeripheral:error])            [self.delegate DidNotifyFailConnectChar:nil withPeripheral:nil error:nil];                return;    }            for (CBCharacteristic *characteristic in service.characteristics)    {        if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:UUIDSTR_ISSC_TRANS_TX]])        {            NSLog(@"Discovered read characteristics:%@ for service: %@", characteristic.UUID, service.UUID);                        _readCharacteristic = characteristic;//保存读的特征                        if ([self.delegate respondsToSelector:@selector(DidFoundReadChar])                [self.delegate DidFoundReadChar:characteristic];                        break;        }    }        for (CBCharacteristic * characteristic in service.characteristics)    {                        if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:UUIDSTR_ISSC_TRANS_RX]])        {            NSLog(@"Discovered write characteristics:%@ for service: %@", characteristic.UUID, service.UUID);            _writeCharacteristic = characteristic;//保存写的特征                        if ([self.delegate respondsToSelector:@selector(DidFoundWriteChar:)])                [self.delegate DidFoundWriteChar:characteristic];                        break;                                }    }        if ([self.delegate respondsToSelector:@selector(DidFoundCharacteristic:withPeripheral:error:)])        [self.delegate DidFoundCharacteristic:nil withPeripheral:nil error:nil];    }
相信你应该已经注意到了，回调函数都是以"did"开头的，这些函数不用你调用，达到条件后系统后自动调用。


5与外设做数据交互(explore and interact)

发送数据很简单，我们可以封装一个如下的函数:

[objc] view plaincopyprint?

• //写数据
• -(void)writeChar:(NSData *)data
• {
•     [_testPeripheral writeValue:data forCharacteristic:_writeCharacteristic type:CBCharacteristicWriteWithResponse];
• }
  

//写数据-(void)writeChar:(NSData *)data{    [_testPeripheral writeValue:data forCharacteristic:_writeCharacteristic type:CBCharacteristicWriteWithResponse];}

_testPeripheral和_writeCharacteristic是前面我们保存的设备对象和可以读写的特征。

然后我们可以在外部调用它，比如当然我要触发刷卡时，先组好数据包，然后调用发送函数:

[objc] view plaincopyprint?

• -(void)msrRead
• {
•     unsigned char command[512] = {0};
•     unsigned charchar *pTmp;
•     int nSendLen = 0;
•     unsigned char ucCrc[3] = {0};
•     _commandType = COMMAND_MSR_READ;
•     pTmp = command;
•     *pTmp = 0x02;//start
•     pTmp++;
•     *pTmp = 0xc1;//main cmd
•     pTmp++;
•     *pTmp = 0x07;//sub cmd
•     pTmp++;
•     nSendLen = 2;
•     *pTmp = nSendLen/256;
•     pTmp++;
•     *pTmp = nSendLen%256;
•     pTmp++;
•     *pTmp = 0x00;//sub cmd
•     pTmp++;
•     *pTmp = 0x00;//sub cmd
•     pTmp++;
•     Crc16CCITT(command+1,pTmp-command-1,ucCrc);
•     memcpy(pTmp,ucCrc,2);
•     NSData *data = [[NSData alloc] initWithBytes:&command length:9];
•     NSLog(@"send data:%@", data);
•     [g_BLEInstance.recvData setLength:0];
•     [g_BLEInstance writeChar:data];
• }
  

-(void)msrRead{        unsigned char command[512] = {0};    unsigned char *pTmp;    int nSendLen = 0;    unsigned char ucCrc[3] = {0};        _commandType = COMMAND_MSR_READ;        pTmp = command;            *pTmp = 0x02;//start        pTmp++;            *pTmp = 0xc1;//main cmd        pTmp++;        *pTmp = 0x07;//sub cmd        pTmp++;                nSendLen = 2;            *pTmp = nSendLen/256;        pTmp++;        *pTmp = nSendLen%256;        pTmp++;        *pTmp = 0x00;//sub cmd        pTmp++;        *pTmp = 0x00;//sub cmd        pTmp++;                Crc16CCITT(command+1,pTmp-command-1,ucCrc);        memcpy(pTmp,ucCrc,2);            NSData *data = [[NSData alloc] initWithBytes:&command length:9];    NSLog(@"send data:%@", data);    [g_BLEInstance.recvData setLength:0];        [g_BLEInstance writeChar:data];}


数据的读分为两种，一种是直接读(reading directly),另外一种是订阅(subscribe)。从名字也能基本理解两者的不同。实际使用中具体用一种要看具体的应用场景以及特征本身的属性。前一个好理解，特征本身的属性是指什么呢？特征有个properties字段(characteristic.properties),它是一个整型值,有如下几个定义:

[objc] view plaincopyprint?

• enum {
•      CBCharacteristicPropertyBroadcast = 0x01,
•      CBCharacteristicPropertyRead = 0x02,
•      CBCharacteristicPropertyWriteWithoutResponse = 0x04,
•      CBCharacteristicPropertyWrite = 0x08,
•      CBCharacteristicPropertyNotify = 0x10,
•      CBCharacteristicPropertyIndicate = 0x20,
•      CBCharacteristicPropertyAuthenticatedSignedWrites = 0x40,
•      CBCharacteristicPropertyExtendedProperties = 0x80,
•      };
  

enum {     CBCharacteristicPropertyBroadcast = 0x01,     CBCharacteristicPropertyRead = 0x02,     CBCharacteristicPropertyWriteWithoutResponse = 0x04,     CBCharacteristicPropertyWrite = 0x08,     CBCharacteristicPropertyNotify = 0x10,     CBCharacteristicPropertyIndicate = 0x20,     CBCharacteristicPropertyAuthenticatedSignedWrites = 0x40,     CBCharacteristicPropertyExtendedProperties = 0x80,     };

比如说，你要交互的特征，它的properties的值是0x10,表示你只能用订阅的方式来接收数据。我这里是用订阅的方式，启动订阅的代码如下:

[objc] view plaincopyprint?

• //监听设备
• -(void)startSubscribe
• {
•     [_testPeripheral setNotifyValue:YES forCharacteristic:_readCharacteristic];
• }
  

//监听设备-(void)startSubscribe{    [_testPeripheral setNotifyValue:YES forCharacteristic:_readCharacteristic];}


当设备有数据返回时，同样是通过一个系统回调通知我，如下所示:

[objc] view plaincopyprint?

• - (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
• {
•     if (error)
•     {
•         NSLog(@"Error updating value for characteristic %@ error: %@", characteristic.UUID, [error localizedDescription]);
•         if ([_mainMenuDelegate respondsToSelector:@selector(DidNotifyReadError:)])
•             [_mainMenuDelegate DidNotifyReadError:error];
•         return;
•     }
•     [_recvData appendData:characteristic.value];
•     if ([_recvData length] >= 5)//已收到长度
•     {
•         unsigned charchar *buffer = (unsigned charchar *)[_recvData bytes];
•         int nLen = buffer[3]*256 + buffer[4];
•         if ([_recvData length] == (nLen+3+2+2))
•         {
•             //接收完毕，通知代理做事
•             if ([_mainMenuDelegate respondsToSelector:@selector(DidNotifyReadData)])
•                 [_mainMenuDelegate DidNotifyReadData];
•         }
•     }
• }
  

- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{            if (error)     {        NSLog(@"Error updating value for characteristic %@ error: %@", characteristic.UUID, [error localizedDescription]);                if ([_mainMenuDelegate respondsToSelector:@selector(DidNotifyReadError:)])            [_mainMenuDelegate DidNotifyReadError:error];                return;    }        [_recvData appendData:characteristic.value];            if ([_recvData length] >= 5)//已收到长度    {        unsigned char *buffer = (unsigned char *)[_recvData bytes];        int nLen = buffer[3]*256 + buffer[4];        if ([_recvData length] == (nLen+3+2+2))        {            //接收完毕，通知代理做事            if ([_mainMenuDelegate respondsToSelector:@selector(DidNotifyReadData)])                [_mainMenuDelegate DidNotifyReadData];                    }    }}


6 断开连接(disconnect)

这个比较简单，只需要一个API就行了,代码如下:

[objc] view plaincopyprint?

• //主动断开设备
• -(void)disConnect
• {
•     if (_testPeripheral != nil)
•     {
•         NSLog(@"disConnect start");
•         [manager cancelPeripheralConnection:_testPeripheral];
•     }
• }
  

//主动断开设备-(void)disConnect{        if (_testPeripheral != nil)    {        NSLog(@"disConnect start");        [manager cancelPeripheralConnection:_testPeripheral];    }}

六 成果展示

上几张效果图，UI没怎么修饰，主要关注功能,实现了读取磁道信息，与金融ic卡进行APDU交互等功能。