基于iOS的蓝牙开发

导语:

最近几天在做一个关于蓝牙与血压计和血氧仪交互方面的东西,刚开始使用的是babybluetooth(但封装的内容我不会使用,于是就自己写了一个工具类)。在此带来一些关于蓝牙开发的分享。

1.蓝牙基础知识

CoreBluetooth框架的核心是peripheral(外设)和central(中心),发起连接的是 central,被连接的设备为 peripheral。在移动端开发中,我们通常使用的是中心模式。

2.中心模式的流程

  1. 建立中心
  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 Characteristics的 Descriptor 和 Descriptor 的值
  1. 与外设做数据交互(explore and interact)
  2. 订阅 Characteristic 的通知
  3. 断开连接(disconnect)

3.具体实现代码

创建中心管理者

#import 
typedef NS_ENUM(NSInteger,BDBlueToothType){
    BDBlueToothType_Oximeter = 1,//血氧仪
    BDBlueToothType_Hamnatodynamometer //血压计
};
//蓝牙搜索到的设备数组
typedef void(^PeripheralBlock)(NSMutableArray *);
//读到的数据
typedef void(^ReadValueBlock)(NSString *);
@interface BDBlueToothHelper : NSObject
//外设
@property(nonatomic, strong) CBPeripheral* myPeripheral;
//中心管理工具
@property (nonatomic, strong) CBCentralManager* myCentralManager;

初始化开始扫描

self.myCentralManager = [[CBCentralManager alloc]initWithDelegate:self queue:nil options:nil];
必须实现的代理方法
//查看蓝牙服务
- (void)centralManagerDidUpdateState:(CBCentralManager *)central{
    switch (central.state) {
        case CBCentralManagerStatePoweredOn:
            BDLog(@"蓝牙已打开, 请扫描外设!");
            //搜索外设
            [self.myCentralManager scanForPeripheralsWithServices:nil options:@{CBCentralManagerOptionShowPowerAlertKey:@YES}];
            break;
        case CBCentralManagerStatePoweredOff:
            BDLog(@"蓝牙关闭...");
            break;
        default:
            break;
    }
}

#pragma mark 搜索到设备之后会调用代理方法
- (void)centralManager:(CBCentralManager *)central // 中心管理者
 didDiscoverPeripheral:(CBPeripheral *)peripheral // 外设
     advertisementData:(NSDictionary *)advertisementData // 外设携带的数据
                  RSSI:(NSNumber *)RSSI{ // 外设发出的蓝牙信号强度
    BDLog(@"已发现 peripheral: %@ rssi: %@, name: %@ advertisementData: %@", peripheral, RSSI, peripheral.name, advertisementData);
    //这里可以做一些过滤操作
    if ([_myPeripherals containsObject:peripheral]) {
        
    }else
    {
        //找到的设备必须持有它,否则CBCentralManager中也不会保存peripheral
        [_myPeripherals addObject:peripheral];
    }
   //将搜索的设备回调给控制器的tableview使用,刷新表格
    if (self.perlists) {
        self.perlists(_myPeripherals);
    }
    
}

建立连接

//self.myPeripheral在cell点击时的赋值
[self.myCentralManager connectPeripheral:self.myPeripheral options:nil];

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、断开都会进入到相应的代理

#pragma mark 连接外设成功
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{
    BDLog(@"成功外设连接");
    //设置外设的代理
    [self.myPeripheral setDelegate:self];
    //外设发现服务,传nil代表不过滤
    // 这里会触发外设的代理方法 - (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
    [self.myPeripheral discoverServices:nil];
}

#pragma mark 掉线时调用 丢失连接
- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"蓝牙连接已断开" delegate:nil cancelButtonTitle:nil otherButtonTitles:@"关闭", nil];
    [alert show];
    [self closeConnect];
    BDLog(@"丢失连接");
}

#pragma mark 连接外设失败
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error{
    BDLog(@"连接外设失败%@", error);
}

扫描服务和特征

#pragma mark 发现服务
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{
    BDLog(@"发现服务!");
    for(CBService* s in peripheral.services){
        NSLog(@"%d :服务 UUID: %@(%@)", i, s.UUID.data, s.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:s];
        [self.nServices addObject:s];
    }
}

#pragma mark 发现外设服务里的特征的时候调用的代理方法
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{
    for(CBCharacteristic* c in service.characteristics){
        BDLog(@"特征 UUID: %@ (%@)", c.UUID.data, c.UUID);
        
        if (self.toothType == BDBlueToothType_Oximeter) {//血氧仪
            if([c.UUID isEqual:[CBUUID UUIDWithString:@"FFF1"]]){
                self.writeCharacteristic = c;
                
                BDLog(@"找到WRITE : %@", c);
            }else if([c.UUID isEqual:[CBUUID UUIDWithString:@"FFF4"]]){
                self.readCharacteristic = c;
                
                [self.myPeripheral setNotifyValue:YES forCharacteristic:c];
                [self.myPeripheral readValueForCharacteristic:c];
                NSLog(@"找到READ : %@", c);
            }
        }else if (self.toothType == BDBlueToothType_Hamnatodynamometer){//血压计
            if ([c.UUID isEqual:[CBUUID UUIDWithString:@"FFE1"]]) {
                BDLog(@"血压计 %zd - %@",c.properties,c.descriptors);
                self.readCharacteristic = c;
                self.writeCharacteristic = c;
                [self.myPeripheral setNotifyValue:YES forCharacteristic:c];
                [self.myPeripheral readValueForCharacteristic:c];
            }
        }
        
    }
}

与外设进行数据交互

#pragma mark 获取外设发来的数据,不论是read和notify,获取数据都从这个方法中读取
- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
    [peripheral readRSSI];
    
    NSData* data = characteristic.value;
    
    if (!data.length) {
        return;
    }
    
    NSString* value = [self hexadecimalString:data];
    
    if (self.toothType == BDBlueToothType_Oximeter) { //血氧仪
        
        if([characteristic.UUID isEqual:[CBUUID UUIDWithString:@"FFF4"]]){
            if (value.length) {
                self.readValue(value);
            }
//            BDLog(@"characteristic : %@, data : %@, value : %@", characteristic, data, value);
        }

    }else if (self.toothType == BDBlueToothType_Hamnatodynamometer){ //血压计
        
        if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:@"FFE1"]]) {
            if (value.length) {
                self.readValue(value);
            }
//            BDLog(@"characteristic : %@, data : %@, value : %@", characteristic, data, value);
        }
    }
}

//中心读取外设实时数据
- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
    if(error){
        BDLog(@"Error changing notification state: %@", error.localizedDescription);
    }
    
    if(characteristic.isNotifying){
        [peripheral readValueForCharacteristic:characteristic];
    }else{
        BDLog(@"Notification stopped on %@. Disconnting", characteristic);
        [self.myCentralManager cancelPeripheralConnection:self.myPeripheral];
    }
}

//向peripheral中写入数据
- (void)writeToPeripheral:(NSString *)data{
    if(!_writeCharacteristic){
        BDLog(@"writeCharacteristic is nil!");
        return;
    }
    NSData* value = [self dataWithHexstring:data];
    
    [_myPeripheral writeValue:value forCharacteristic:_writeCharacteristic type:CBCharacteristicWriteWithResponse];
}

//向peripheral中写入数据后的回调函数
- (void)peripheral:(CBPeripheral*)peripheral didWriteValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
    if (error) {
        BDLog(@"error %@",error);
    }
    BDLog(@"write value success : %@", characteristic);
}

用到的私有方法

//将传入的NSData类型转换成NSString并返回
- (NSString*)hexadecimalString:(NSData *)data{
    NSString* result;
    const unsigned char* dataBuffer = (const unsigned char*)[data bytes];
    if(!dataBuffer){
        return nil;
    }
    NSUInteger dataLength = [data length];
    NSMutableString* hexString = [NSMutableString stringWithCapacity:(dataLength * 2)];
    for(int i = 0; i < dataLength; i++){
        [hexString appendString:[NSString stringWithFormat:@"%02lx", (unsigned long)dataBuffer[i]]];
    }
    result = [NSString stringWithString:hexString];
    return result;
}

//将传入的NSString类型转换成NSData并返回
- (NSData*)dataWithHexstring:(NSString *)hexstring{
    NSMutableData* data = [NSMutableData data];
    int idx;
    for(idx = 0; idx + 2 <= hexstring.length; idx += 2){
        NSRange range = NSMakeRange(idx, 2);
        NSString* hexStr = [hexstring substringWithRange:range];
        NSScanner* scanner = [NSScanner scannerWithString:hexStr];
        unsigned int intValue;
        [scanner scanHexInt:&intValue];
        [data appendBytes:&intValue length:1];
    }
    return data;
}

相关的蓝牙文档

基于iOS的蓝牙开发_第1张图片
屏幕快照 2017-07-24 上午11.43.21.png

参考文档

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