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【投稿】iOS 蓝牙开发(二)iOS 连接外设的代码实现

2015-09-17 09:11 编辑: lansekuangtu 分类:iOS开发 来源:刘彦玮 投稿

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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)

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 
    @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

本文代码存放目录是BleDemo

如果大家支持,请follow我的github账号,并star我的项目,有其他问题可以在blog中给我留言 blog的RSS订阅


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