iOS-蓝牙的简单使用

蓝牙实现方案

之前项目有用到蓝牙,这里记录一下蓝牙的一些简单使用.

iOS提供了4个用于实现蓝牙连接的方案:

1. ExternalAccessory.framework

提供了配件链接iOS的通道,可用于第三方蓝牙设备交互(蓝牙设备必须需要苹果MFI认证,比较麻烦)

2.MultipeerConnectivity.framework

iOS7引入的多点连接,只能用于Apple设备,可在较近的距离基于蓝牙和WIFI发现和连接实现进场通信,有点和AirDrop类似,不过AirDrop必须同时打开WiFi和蓝牙,而且要保持较近的距离 ( 其过程相当于A放出广播,B用于搜索,B搜到之后向A发邀请,请求建立连接,A接受之后向B发送一个会话,建立连接)

MCPeerID *_peerID = [[MCPeerID alloc] initWithDisplayName:[UIDevice currentDevice].name];//给设备自定义个名字
MCSession *_session = [[MCSession alloc] initWithPeer:_peerID];//创建会话
_session.delegate = self;//遵守协议
MCAdvertiserAssistant *_advertiser = [[MCAdvertiserAssistant alloc] initWithServiceType:@"chat-files"
                                                                   discoveryInfo:nil
                                                                   session:_session];
//初始化广播服务,serviceType是类型标识符,通过文本描述来让浏览器发现广播者,只有相同的serviceType才能相互连接(要求1-15个字符,只能包含ASCII小写字母,数字和连字符)
[_advertiser start]; //开始广播   stop关闭广播

MCBrowserViewController *_browser = [[MCBrowserViewController alloc] initWithServiceType:@"chat-files"session:_session]; // 创建视图浏览器
_browser.delegate = self; //遵守协议
[self presentViewController: _browser animated:YES completion:nil]; //弹出视窗

//
-(void)browserViewControllerDidFinish:(MCBrowserViewController *)browserViewController{//完成
    [_browser dismissViewControllerAnimated:YES completion:nil];
}

-(void)browserViewControllerWasCancelled:(MCBrowserViewController *)browserViewController{//取消
    [_browser dismissViewControllerAnimated:YES completion:nil];
}

//浏览器提供连接功能 ,等连接之后就根据情况实现方法
-(void)session:(MCSession *)session peer:(MCPeerID *)peerID didChangeState:(MCSessionState)state{
    //新的连接发生时,会被调用   state状态如下:
    //MCSessionStateNotConnected,     // Not connected to the session.
    //    MCSessionStateConnecting,       // Peer is connecting to the session.
    //    MCSessionStateConnected    
}


-(void)session:(MCSession *)session didReceiveData:(NSData *)data fromPeer:(MCPeerID *)peerID{
    //接受数据
}


-(void)session:(MCSession *)session didStartReceivingResourceWithName:(NSString *)resourceName fromPeer:(MCPeerID *)peerID withProgress:(NSProgress *)progress{
    //开始接受资源
}


-(void)session:(MCSession *)session didFinishReceivingResourceWithName:(NSString *)resourceName fromPeer:(MCPeerID *)peerID atURL:(NSURL *)localURL withError:(NSError *)error{
    //结束接收资源
}


-(void)session:(MCSession *)session didReceiveStream:(NSInputStream *)stream withName:(NSString *)streamName fromPeer:(MCPeerID *)peerID{
    //接收流
}

[_session sendData: dataToSend toPeers:_session.connectedPeers withMode:MCSessionSendDataReliable error:&error]; //发送数据给所有连接的设备

连接流程图.png

3.GameKit.framework

用于Apple设备之间的连接,更多用于游戏方面,从iOS7废弃.此方案可以增加对等连接,无需连接到互联网

GKPeerPickerController *gpp = [[GKPeerPickerController alloc] init];//创建查找设备控制器
gpp.connectionTypesMask = GKPeerPickerConnectionTypeNearby | GKPeerPickerConnectionTypeOnline;
//nearby指蓝牙 online指WIFI
gpp.delegate = self; // 遵守协议
[gpp show];//弹出控制器

//协议
- (void)peerPickerController:(GKPeerPickerController *)picker didConnectPeer:(NSString *)peerID toSession:(GKSession *)session
{
    //设备连接成功后调用方法
    [self.session setDataReceiveHandler:self withContext:nil]; // 设置数据接受者
    [picker dismiss]; // 退出查找设备的控制器
}

- (void) receiveData:(NSData *)data fromPeer:(NSString *)peer inSession: (GKSession *)session context:(void *)context
{
    //接收数据的时候会调用该方法
}

[self.session sendDataToAllPeers: data withDataMode:GKSendDataReliable error:nil];//发送数据
[self.session sendData:data toPeers: peers withDataMode:GKSendDataReliable error:nil];//往指定peer发送数据

4.CoreBluetooth.framework (蓝牙4.0)

以低功耗著称,可用于第三方蓝牙设备交互,对硬件上是有一定要求的，iPhone 4S及以后的设备，第三代iPad及以后的设备是支持这一标准的

核心结构图如下

CoreBluetooth结构图.png

每个蓝牙设备必有一个或多个Service ,一个Service有若干个Characteristic,它们都是用UUID来唯一识别

@property(nonatomic,strong)CBCentralManager *_mgr;//中央管理者

//初始化中央管理者
 _mgr = [[CBCentralManager alloc] initWithDelegate:self queue:nil];

//遵守协议
- (void)centralManagerDidUpdateState:(CBCentralManager *)central
{
    //状态发生改变的时候会执行该方法(蓝牙4.0没有打开变成打开状态就会调用该方法)
     switch (central.state) {
        case CBCentralManagerStatePoweredOn:
            NSLog(@"打开，可用");
            //扫描周围的蓝牙 options参数 允许中央设备多次收到曾经监听到的设备的消息
            [_mgr scanForPeripheralsWithServices:nil options:@{CBCentralManagerScanOptionAllowDuplicatesKey:@(NO)}];
            break;
        case CBCentralManagerStatePoweredOff:
            NSLog(@"可用，未打开");
            break;
        case CBCentralManagerStateUnsupported:
            NSLog(@"SDK不支持");
            break;
        case CBCentralManagerStateUnauthorized:
            NSLog(@"程序未授权");
            break;
        case CBCentralManagerStateResetting:
            NSLog(@"CBCentralManagerStateResetting");
            break;
        case CBCentralManagerStateUnknown:
            NSLog(@"CBCentralManagerStateUnknown");
            break;
}

//搜索到蓝牙设备之后调用
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
{
//一次返回一个设备信息 RSSI为信号强度，可以将信息放入数组中
   //peripheral.identifier.UUIDString 蓝牙设备的唯一标识
}

//连接设备
[self.mgr connectPeripheral:peripheral options:@{CBConnectPeripheralOptionNotifyOnDisconnectionKey:@(YES)}];

[self.manager stopScan];//停止扫描外设

//连接外围设备之后调用
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral
{
    // 1.扫描所有的服务
    // serviceUUIDs:指定要扫描该外围设备的哪些服务(传nil,扫描所有的服务)
    [peripheral discoverServices:nil];
    
    // 2.设置代理，为了后面查询外设的服务和外设的特性
    //协议
    peripheral.delegate = self;
}
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(nullable NSError *)error
{
    //连接失败调用
    NSLog(@"didFailToConnectPeripheral");
}

//遵循协议
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
{
//发现外围设备的服务
    for (CBService *serivce in peripheral.services) {
        if ([serivce.UUID.UUIDString isEqualToString:@"123456"]) {
            // characteristicUUIDs : 可以指定想要扫描的特征(传nil,扫描所有的特征)
            [peripheral discoverCharacteristics:nil forService:serivce];
        }
    }
}

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
{
//发现服务后，当扫描到服务的特征时调用
    for (CBCharacteristic *characteristic in service.characteristics) {
        if ([characteristic.UUID.UUIDString isEqualToString:@"456"]) {
            // 拿到特征,和外围设备进行交互
             CBCharacteristicProperties proper = characteristic.properties;   
             if (proper & CBCharacteristicPropertyBroadcast){} //广播特性
             if (proper & CBCharacteristicPropertyRead){
             //读特性
                   [peripheral readValueForCharacteristic:characteristic];
             }
             if (proper & CBCharacteristicPropertyWriteWithoutResponse){
             //写特性不需要响应，可以保存特征以便后续写数据
             }
             if (properties & CBCharacteristicPropertyWrite) {
             //如果具备写入值的特性，这个应该会有一些响应
             }
             if (properties & CBCharacteristicPropertyNotify) {
             //如果具备通知的特性
             [peripheral setNotifyValue:YES forCharacteristic:character];
             } 
        }
    }
}

//通知代理
- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(nonnull CBCharacteristic *)characteristic error:(nullable NSError *)error
{
    CBCharacteristicProperties properties = characteristic.properties;
    if (properties & CBCharacteristicPropertyRead) {
        //如果具备读特性，即可以读取特性的value
        [peripheral readValueForCharacteristic:characteristic];
    }
}

//读取特性中的值调用
- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
{
    NSData *data = characteristic.value;
    if (data.length <= 0) {
        return;
    }
    NSString *info = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
}

//往设备写数据
 [peripheral writeValue: data forCharacteristic: chatacter type:CBCharacteristicWriteWithoutResponse];

//取消与设备连接
[self.manager cancelPeripheralConnection:peripheral];
//断开连接的代理
- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(nullable NSError *)error;