iOS连接外设的代码实现
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
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建立中心角色
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扫描外设(discover)
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连接外设(connect)
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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
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Xcode
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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)
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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