ios蓝牙开发（三）app作为外设被连接的实现

本是古典何须时尚 2022-07-13 13:49 123阅读 0赞

再上一节说了app作为central连接peripheral的情况，这一节介绍如何使用app发布一个peripheral，给其他的central连接

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## ![CoreBluetoothFramework.jpeg][] ##

还是这张图，central模式用的都是左边的类，而peripheral模式用的是右边的类

## peripheral模式的流程 ##

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1. 打开peripheralManager，设置peripheralManager的委托
    2. 创建characteristics，characteristics的description 创建service，把characteristics添加到service中，再把service添加到peripheralManager中
    3. 开启广播advertising
    4. 对central的操作进行响应
        - 4.1 读characteristics请求
        - 4.2 写characteristics请求
        - 4.4 订阅和取消订阅characteristics

## 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），如果不行可以使用osx程序调试
      3 蓝牙外设

## 实现步骤 ##

#### 1. 打开peripheralManager，设置peripheralManager的委托 ####

设置当前ViewController实现CBPeripheralManagerDelegate委托

@interface BePeripheralViewController : UIViewController<CBPeripheralManagerDelegate>

初始化peripheralManager

/*
         和CBCentralManager类似，蓝牙设备打开需要一定时间，打开成功后会进入委托方法
         - (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral;
         模拟器永远也不会得CBPeripheralManagerStatePoweredOn状态
         */
        peripheralManager = [[CBPeripheralManager alloc]initWithDelegate:self queue:nil];

#### 2. 创建characteristics，characteristics的description ，创建service，把characteristics添加到service中，再把service添加到peripheralManager中 ####

在委托方法 `- (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral`中，当peripheral成功打开后，才可以配置service和characteristics。这里创建的service和chara对象是CBMutableCharacteristic和CBMutableService。他们的区别就像NSArray和NSMutableArray区别类似。我们先创建characteristics和description，description是characteristics的描述，描述分很多种，这里不细说了，常用的就是CBUUIDCharacteristicUserDescriptionString。

//peripheralManager状态改变
    - (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral{
        switch (peripheral.state) {
                //在这里判断蓝牙设别的状态  当开启了则可调用  setUp方法(自定义)
            case CBPeripheralManagerStatePoweredOn:
                NSLog(@"powered on");
                [info setText:[NSString stringWithFormat:@"设备名%@已经打开，可以使用center进行连接",LocalNameKey]];
                [self setUp];
                break;
            case CBPeripheralManagerStatePoweredOff:
                NSLog(@"powered off");
                [info setText:@"powered off"];
                break;
    
            default:
                break;
        }
    }

//配置bluetooch的
     -(void)setUp{
    
            //characteristics字段描述
            CBUUID *CBUUIDCharacteristicUserDescriptionStringUUID = [CBUUID UUIDWithString:CBUUIDCharacteristicUserDescriptionString];
    
            /*
             可以通知的Characteristic
             properties：CBCharacteristicPropertyNotify
             permissions CBAttributePermissionsReadable
             */
            CBMutableCharacteristic *notiyCharacteristic = [[CBMutableCharacteristic alloc]initWithType:[CBUUID UUIDWithString:notiyCharacteristicUUID] properties:CBCharacteristicPropertyNotify value:nil permissions:CBAttributePermissionsReadable];
    
            /*
             可读写的characteristics
             properties：CBCharacteristicPropertyWrite | CBCharacteristicPropertyRead
             permissions CBAttributePermissionsReadable | CBAttributePermissionsWriteable
             */
            CBMutableCharacteristic *readwriteCharacteristic = [[CBMutableCharacteristic alloc]initWithType:[CBUUID UUIDWithString:readwriteCharacteristicUUID] properties:CBCharacteristicPropertyWrite | CBCharacteristicPropertyRead value:nil permissions:CBAttributePermissionsReadable | CBAttributePermissionsWriteable];
            //设置description
            CBMutableDescriptor *readwriteCharacteristicDescription1 = [[CBMutableDescriptor alloc]initWithType: CBUUIDCharacteristicUserDescriptionStringUUID value:@"name"];
            [readwriteCharacteristic setDescriptors:@[readwriteCharacteristicDescription1]];
    
    
            /*
             只读的Characteristic
             properties：CBCharacteristicPropertyRead
             permissions CBAttributePermissionsReadable
             */
            CBMutableCharacteristic *readCharacteristic = [[CBMutableCharacteristic alloc]initWithType:[CBUUID UUIDWithString:readCharacteristicUUID] properties:CBCharacteristicPropertyRead value:nil permissions:CBAttributePermissionsReadable];
    
    
            //service1初始化并加入两个characteristics
            CBMutableService *service1 = [[CBMutableService alloc]initWithType:[CBUUID UUIDWithString:ServiceUUID1] primary:YES];
            [service1 setCharacteristics:@[notiyCharacteristic,readwriteCharacteristic]];
    
            //service2初始化并加入一个characteristics
            CBMutableService *service2 = [[CBMutableService alloc]initWithType:[CBUUID UUIDWithString:ServiceUUID2] primary:YES];
            [service2 setCharacteristics:@[readCharacteristic]];
    
            //添加后就会调用代理的- (void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error
            [peripheralManager addService:service1];
            [peripheralManager addService:service2];
     }

#### 3. 开启广播advertising ####

//perihpheral添加了service
    - (void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error{
        if (error == nil) {
            serviceNum++;
        }
    
        //因为我们添加了2个服务，所以想两次都添加完成后才去发送广播
        if (serviceNum==2) {
            //添加服务后可以在此向外界发出通告 调用完这个方法后会调用代理的
            //(void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral error:(NSError *)error
            [peripheralManager startAdvertising:@{
                                                  CBAdvertisementDataServiceUUIDsKey : @[[CBUUID UUIDWithString:ServiceUUID1],[CBUUID UUIDWithString:ServiceUUID2]],
                                                  CBAdvertisementDataLocalNameKey : LocalNameKey
                                                 }
             ];
    
        }
    
    }
    
    //peripheral开始发送advertising
    - (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral error:(NSError *)error{
        NSLog(@"in peripheralManagerDidStartAdvertisiong");
    }

#### 4. 对central的操作进行响应 ####

- 4.1 读characteristics请求
    - 4.2 写characteristics请求
    - 4.3 订阅和取消订阅characteristics

//订阅characteristics
    -(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didSubscribeToCharacteristic:(CBCharacteristic *)characteristic{
        NSLog(@"订阅了 %@的数据",characteristic.UUID);
        //每秒执行一次给主设备发送一个当前时间的秒数
        timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(sendData:) userInfo:characteristic  repeats:YES];
    }
    
    //取消订阅characteristics
    -(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didUnsubscribeFromCharacteristic:(CBCharacteristic *)characteristic{
        NSLog(@"取消订阅 %@的数据",characteristic.UUID);
        //取消回应
        [timer invalidate];
    }
    
    //发送数据，发送当前时间的秒数
    -(BOOL)sendData:(NSTimer *)t {
        CBMutableCharacteristic *characteristic = t.userInfo;
        NSDateFormatter *dft = [[NSDateFormatter alloc]init];
        [dft setDateFormat:@"ss"];
        NSLog(@"%@",[dft stringFromDate:[NSDate date]]);
    
        //执行回应Central通知数据
        return  [peripheralManager updateValue:[[dft stringFromDate:[NSDate date]] dataUsingEncoding:NSUTF8StringEncoding] forCharacteristic:(CBMutableCharacteristic *)characteristic onSubscribedCentrals:nil];
    
    }
    
    
    //读characteristics请求
    - (void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveReadRequest:(CBATTRequest *)request{
        NSLog(@"didReceiveReadRequest");
        //判断是否有读数据的权限
        if (request.characteristic.properties & CBCharacteristicPropertyRead) {
            NSData *data = request.characteristic.value;
            [request setValue:data];
            //对请求作出成功响应
            [peripheralManager respondToRequest:request withResult:CBATTErrorSuccess];
        }else{
            [peripheralManager respondToRequest:request withResult:CBATTErrorWriteNotPermitted];
        }
    }
    
    
    //写characteristics请求
    - (void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveWriteRequests:(NSArray *)requests{
        NSLog(@"didReceiveWriteRequests");
        CBATTRequest *request = requests[0];
    
        //判断是否有写数据的权限
        if (request.characteristic.properties & CBCharacteristicPropertyWrite) {
            //需要转换成CBMutableCharacteristic对象才能进行写值
            CBMutableCharacteristic *c =(CBMutableCharacteristic *)request.characteristic;
            c.value = request.value;
            [peripheralManager respondToRequest:request withResult:CBATTErrorSuccess];
        }else{
            [peripheralManager respondToRequest:request withResult:CBATTErrorWriteNotPermitted];
        }
    
    
    }

## 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][Link 1]

本文代码存放目录是BleDemo

[CoreBluetoothFramework.jpeg]: /images/20220713/3975a99c348249f1b8803fa24ea6cf30.png
[Link 1]: https://github.com/coolnameismy/demo