iOS连接外设的代码实现

Ivey1982 9年前

来自: http://www.cocoachina.com/ios/20160217/15294.html

上一篇文章介绍了蓝牙的技术知识,这里我们具体说明一下中心模式的应用场景。主设备(手机去扫描连接外设,发现外设服务和属性,操作服务和属性的应用。一般来说,外设(蓝牙设备,比如智能手环之类的东西), 会由硬件工程师开发好,并定义好设备提供的服务,每个服务对于的特征,每个特征的属性(只读,只写,通知等等),本文例子的业务场景,就是用一手机app去读写蓝牙设备。

##ios连接外设的代码实现流程

  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)

- 4.1 获取外设的services

- 4.2 获取外设的Characteristics,获取Characteristics的值,获取Characteristics的Descriptor和Descriptor的值

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)

8.模拟器蓝牙调试,慎用,最好还是用真机去调试。

##准备环境

  1. Xcode

  2. 开发证书和手机(蓝牙程序需要使用使用真机调试,使用模拟器也可以调试,但是方法很蛋疼,我会放在最后说)

  3. 蓝牙外设

##实现步骤

###1 导入CoreBluetooth头文件,建立主设备管理类,设置主设备委托

#import [CoreBluetooth/CoreBluetooth.h](因识别问题,此处将尖括号改为方括号)      @interface ViewController : UIViewController    @interface ViewController (){          //系统蓝牙设备管理对象,可以把他理解为主设备,通过他,可以去扫描和链接外设          CBCentralManager *manager;      }        - (void)viewDidLoad {          [super viewDidLoad];          /*           设置主设备的委托,CBCentralManagerDelegate              必须实现的:              - (void)centralManagerDidUpdateState:(CBCentralManager *)central;//主设备状态改变的委托,在初始化CBCentralManager的适合会打开设备,只有当设备正确打开后才能使用              其他选择实现的委托中比较重要的:              - (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI; //找到外设的委托              - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral;//连接外设成功的委托              - (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//外设连接失败的委托              - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//断开外设的委托          */           //初始化并设置委托和线程队列,最好一个线程的参数可以为nil,默认会就main线程           manager = [[CBCentralManager alloc]initWithDelegate:self queue:dispatch_get_main_queue()];

###2 扫描外设(discover),扫描外设的方法我们放在centralManager成功打开的委托中,因为只有设备成功打开,才能开始扫描,否则会报错。

-(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");                      //开始扫描周围的外设                      /*                       第一个参数nil就是扫描周围所有的外设,扫描到外设后会进入                            - (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI;                       */                      [manager scanForPeripheralsWithServices:nil options:nil];                      break;                  default:                      break;              }            }          //扫描到设备会进入方法          -(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{                NSLog(@"当扫描到设备:%@",peripheral.name);              //接下来可以连接设备          }

###3 连接外设(connect)

//扫描到设备会进入方法          -(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{              //接下连接我们的测试设备,如果你没有设备,可以下载一个app叫lightbule的app去模拟一个设备              //这里自己去设置下连接规则,我设置的是P开头的设备                     if ([peripheral.name hasPrefix:@"P"]){                     /*                         一个主设备最多能连7个外设,每个外设最多只能给一个主设备连接,连接成功,失败,断开会进入各自的委托                      - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral;//连接外设成功的委托                      - (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//外设连接失败的委托                      - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//断开外设的委托                      */                      //连接设备                     [manager connectPeripheral:peripheral options:nil];                 }          }            //连接到Peripherals-成功          - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral          {              NSLog(@">>>连接到名称为(%@)的设备-成功",peripheral.name);          }            //连接到Peripherals-失败          -(void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error          {              NSLog(@">>>连接到名称为(%@)的设备-失败,原因:%@",[peripheral name],[error localizedDescription]);          }            //Peripherals断开连接          - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error{              NSLog(@">>>外设连接断开连接 %@: %@\n", [peripheral name], [error localizedDescription]);            }

###4 扫描外设中的服务和特征(discover)

设备连接成功后,就可以扫描设备的服务了,同样是通过委托形式,扫描到结果后会进入委托方法。但是这个委托已经不再是主设备的委托(CBCentralManagerDelegate),而是外设的委托(CBPeripheralDelegate),这个委托包含了主设备与外设交互的许多 回叫方法,包括获取services,获取characteristics,获取characteristics的值,获取characteristics的Descriptor,和Descriptor的值,写数据,读rssi,用通知的方式订阅数据等等。

4.1获取外设的services

//连接到Peripherals-成功          - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral          {              NSLog(@">>>连接到名称为(%@)的设备-成功",peripheral.name);              //设置的peripheral委托CBPeripheralDelegate              //@interface ViewController : UIViewController            [peripheral setDelegate:self];              //扫描外设Services,成功后会进入方法:-(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{              [peripheral discoverServices:nil];            }          //扫描到Services          -(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{              //  NSLog(@">>>扫描到服务:%@",peripheral.services);              if (error)              {                  NSLog(@">>>Discovered services for %@ with error: %@", peripheral.name, [error localizedDescription]);                  return;              }                for (CBService *service in peripheral.services) {                               NSLog(@"%@",service.UUID);                               //扫描每个service的Characteristics,扫描到后会进入方法: -(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error                               [peripheral discoverCharacteristics:nil forService:service];                           }            }

4.2获取外设的Characteristics,获取Characteristics的值,获取Characteristics的Descriptor和Descriptor的值

//扫描到Characteristics       -(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{           if (error)           {               NSLog(@"error Discovered characteristics for %@ with error: %@", service.UUID, [error localizedDescription]);               return;           }             for (CBCharacteristic *characteristic in service.characteristics)           {               NSLog(@"service:%@ 的 Characteristic: %@",service.UUID,characteristic.UUID);           }             //获取Characteristic的值,读到数据会进入方法:-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error           for (CBCharacteristic *characteristic in service.characteristics){               {                   [peripheral readValueForCharacteristic:characteristic];               }           }             //搜索Characteristic的Descriptors,读到数据会进入方法:-(void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error           for (CBCharacteristic *characteristic in service.characteristics){               [peripheral discoverDescriptorsForCharacteristic:characteristic];           }           }        //获取的charateristic的值      -(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{          //打印出characteristic的UUID和值          //!注意,value的类型是NSData,具体开发时,会根据外设协议制定的方式去解析数据          NSLog(@"characteristic uuid:%@  value:%@",characteristic.UUID,characteristic.value);        }        //搜索到Characteristic的Descriptors      -(void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{            //打印出Characteristic和他的Descriptors           NSLog(@"characteristic uuid:%@",characteristic.UUID);          for (CBDescriptor *d in characteristic.descriptors) {              NSLog(@"Descriptor uuid:%@",d.UUID);          }        }      //获取到Descriptors的值      -(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForDescriptor:(CBDescriptor *)descriptor error:(NSError *)error{          //打印出DescriptorsUUID 和value          //这个descriptor都是对于characteristic的描述,一般都是字符串,所以这里我们转换成字符串去解析          NSLog(@"characteristic uuid:%@  value:%@",[NSString stringWithFormat:@"%@",descriptor.UUID],descriptor.value);      }

###5 把数据写到Characteristic中

//写数据      -(void)writeCharacteristic:(CBPeripheral *)peripheral                  characteristic:(CBCharacteristic *)characteristic                           value:(NSData *)value{            //打印出 characteristic 的权限,可以看到有很多种,这是一个NS_OPTIONS,就是可以同时用于好几个值,常见的有read,write,notify,indicate,知知道这几个基本就够用了,前连个是读写权限,后两个都是通知,两种不同的通知方式。          /*           typedef NS_OPTIONS(NSUInteger, CBCharacteristicProperties) {           CBCharacteristicPropertyBroadcast= 0x01,           CBCharacteristicPropertyRead= 0x02,           CBCharacteristicPropertyWriteWithoutResponse= 0x04,           CBCharacteristicPropertyWrite= 0x08,           CBCharacteristicPropertyNotify= 0x10,           CBCharacteristicPropertyIndicate= 0x20,           CBCharacteristicPropertyAuthenticatedSignedWrites= 0x40,           CBCharacteristicPropertyExtendedProperties= 0x80,           CBCharacteristicPropertyNotifyEncryptionRequired NS_ENUM_AVAILABLE(NA, 6_0)= 0x100,           CBCharacteristicPropertyIndicateEncryptionRequired NS_ENUM_AVAILABLE(NA, 6_0)= 0x200           };             */          NSLog(@"%lu", (unsigned long)characteristic.properties);              //只有 characteristic.properties 有write的权限才可以写          if(characteristic.properties & CBCharacteristicPropertyWrite){              /*                  最好一个type参数可以为CBCharacteristicWriteWithResponse或type:CBCharacteristicWriteWithResponse,区别是是否会有反馈              */              [peripheral writeValue:value forCharacteristic:characteristic type:CBCharacteristicWriteWithResponse];          }else{              NSLog(@"该字段不可写!");          }          }

###6 订阅Characteristic的通知

    //设置通知      -(void)notifyCharacteristic:(CBPeripheral *)peripheral                  characteristic:(CBCharacteristic *)characteristic{          //设置通知,数据通知会进入:didUpdateValueForCharacteristic方法          [peripheral setNotifyValue:YES forCharacteristic:characteristic];        }        //取消通知      -(void)cancelNotifyCharacteristic:(CBPeripheral *)peripheral                   characteristic:(CBCharacteristic *)characteristic{             [peripheral setNotifyValue:NO forCharacteristic:characteristic];      }

###7 断开连接(disconnect)

//停止扫描并断开连接      -(void)disconnectPeripheral:(CBCentralManager *)centralManager                       peripheral:(CBPeripheral *)peripheral{          //停止扫描          [centralManager stopScan];          //断开连接          [centralManager cancelPeripheralConnection:peripheral];      }

###8 模拟器蓝牙调试,慎用,最好还是用真机去调试。

由于在iPhone 4s之后的iOS才支持BLE,新一代的这些iOS设备又都不便宜,在做测试的时候,用iOS模拟器进行调试,可以节约一些开发成本。怎么在iOS模拟器上调试BLE,

苹果最初给出的说明是,支持BLE的mac机子上可以用模拟器进行调试,并给出了一份技术文档(传送门),恶心的是,后来苹果抽风,又把这份文档移除, 并且把iOS 7.0的模拟器上对BLE的支持也移除掉了(难道是想让大家多买设备测试?Apple sucks.)后面,网上搜了一下,解决办法如下:

1. 买一个CSR蓝牙4.0 USB适配器(某宝上大概30块钱),在机子上插入该物(你懂的)

2. 在Terminal下敲入sudo nvram bluetoothHostControllerSwitchBehavior="never" , 重启Mac。

3. 用XCode 4.6调试代码,在iOS 6.1的模拟器上跑程序(用XCode 5.0跑iOS 7.0模拟器会抛异常,原因上面详诉过了,Apple sucks,你懂的)

如何降低模拟器的IOS版本呢?

XCode->Preferences->Downloads里面有很多simulators你可以下载

选择个6.1的下载好了

代码下载

我博客中大部分示例代码都上传到了github,地址是:https://github.com/coolnameismy/demo, 点击跳转代码下载地址

本文代码存放目录是BleDemo