首先进一则广告：
蓝牙技术联盟(Bluetooth SIG)2010年7月7日宣布，正式采纳蓝牙4.0核心规范（Bluetooth Core Specification Version 4.0 ），并启动对应的认证计划。会员厂商可以提交其产品进行测试，通过后将获得蓝牙4.0标准认证。 该技术拥有极低的运行和待机功耗，使用一粒纽扣电池甚至可连续工作数年之久。所以蓝牙技术还是可以被长久利用的一种链接技术。
然后直接进入正题。
大家也许会注意到一个问题。安卓和安卓手机可以用蓝牙相互链接，但是苹果和苹果手机就不行。因为苹果链接用的是airdrop，所以也就不需要蓝牙传输大文件。大家也就忽略了这个现象。其实airdrop本质也是蓝牙建立链接的。。。。。。。
今天主要就是用一款app去读写蓝牙设备。应用场景就是手机扫描外设，链接外设，找到外设的服务和属性，对服务和属性进行读写操作；
代码实现流程。
1.建立中心管理控制对象
```objc
#import
//系统蓝牙设备中心管理对象可以去扫描和链接外设
CBCentralManager *_manager;
//用于保存被发现设备
NSMutableArray *_discoverPeripherals;
//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()];
//创建外设数组，保存发现的设备。不保存设备会导致代理方法不可用
discoverPeripherals = [[NSMutableArray array];
```
2.扫描外设，只有设备打开状态，才可以扫描。（错误原因之一）
介绍一下
CBCentralManagerDelegate的主要代理方法。
必须实现的：
- (void)centralManagerDidUpdateState:(CBCentralManager *)central;//主设备状态改变的委托，在初始化CBCentralManager的时候会打开设备，只有当设备正确打开后才能使用
其他选择实现的代理方法。
- (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
//工程中的代码不适合直接放出来，就用示例demo中的了。（感谢这些伟大的开发工作者）
这些状态不需要我一一翻译了吧，如果不懂可以私信我。我一定让你自己查字典去。。。
-(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********** 一定要在设备开启状态再扫描外设*********。
/*
第一个参数nil就是扫描周围所有的外设，可以特定你想扫描到的符合要求的设备。扫描到外设后会进入
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI;
*/
[central scanForPeripheralsWithServices:nil options:nil];
break;
default:
break;
}
}
3.扫描完成，进入连接方法进行设备连接。
-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{
NSLog(@"当扫描到设备:%@",peripheral.name);
//这里自己去设置下连接规则，这里就是不同厂商特定设备链接的判断规则。L是我喜欢的字母。
// if ([peripheral.name hasPrefix:@"L"]){
/*
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
//这个没有验证过。没有那么多测试设备。。。。
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral;//连接外设成功的委托
- (void)centra`lManager:(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
*/
//找到的设备必须持有它，否则CBCentralManager中也不会保存peripheral，那么CBPeripheralDelegate中的方法也不会被调用！！（错误之一）
[discoverPeripherals addObject:peripheral];
[central connectPeripheral:peripheral options:nil];
// }
}
//连接到Peripherals-成功（其他操作不是我们想要的，自己做相关处理）
- (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];
}
4.接下来是发现设备的服务，对相关服务中的特性进行操作。
//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];
}
}
//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.解析到这些数据，就可以满足日常计步，心率等一系列只读数据的操作。接下来是向外设写数据。
//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，知道这几个基本就够用了，前几个是读写权限，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！");
}
}
//订阅外设特性的通知。
//设置通知，数据通知会进入：didUpdateValueForCharacteristic方法
[peripheral setNotifyValue:YES forCharacteristic:characteristic];
//取消通知
[peripheral setNotifyValue:NO forCharacteristic:characteristic];
//设置通知和取消通知均可以触发此方法。
- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(nullable NSError *)error;
6.操作完成 或者电量不足要进行停止扫描断开设备操作。
//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];
}
本来蓝牙开发就需要硬件工程师定义好每个硬件对应的服务，每个服务的描述以及服务特性的属性。所以开发中的代码一般都已经定义好了。最重要的就是了解各种方法是什么作用。在各自开发的过程中是否必须用到。为了让大家有个跟更加进一步的了解。接下来我再说一下服务特性的具体读写与订阅。当然我也是搜索了很多资料。借鉴了很多大神的资源。当时在github上下载了好多东西。具体是哪位大神写的也不晓得。反正很崇拜这些人。。。O(∩_∩)O哈哈哈~
我们看一下外设管理类
以上写的是centralManager的内容接下来是peripheralManager。
1.初始化外设管理者
//外设管理者
CBPeripheralManager *_peripheralManager;
//首先初始化外设管理者
peripheralManager = [[CBPeripheralManager alloc]initWithDelegate:self queue:nil];（默认为主队列）
//在你用过之后记得停止广播
//[peripheralManager stopAdvertising];
2.配置蓝牙读写的属性以及描述
//注意此方法是在保证外设在CBPeripheralManagerStatePoweredOn状态下才可调用***********
-(void)initService{
//characteristics字段描述
CBUUID *CBUUIDCharacteristicUserDescriptionStringUUID = [CBUUID UUIDWithString:CBUUIDCharacteristicUserDescriptionString];
/*
可以给主设备发送通知的特性
properties：CBCharacteristicPropertyNotify
许可特性可读
permissions CBAttributePermissionsReadable
*/
CBMutableCharacteristic *notiyCharacteristic = [[CBMutableCharacteristic alloc]initWithType:[CBUUID UUIDWithString:notiyCharacteristicUUID] properties:CBCharacteristicPropertyNotify value:nil permissions:CBAttributePermissionsReadable];
/*
可读写的特性
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];
//serviceOne初始化并加入两个characteristics
CBMutableService *serviceOne = [[CBMutableService alloc]initWithType:[CBUUID UUIDWithString:ServiceUUID1] primary:YES];
NSLog(@"%@",serviceOne.UUID);
[serviceOne setCharacteristics:@[notiyCharacteristic,readwriteCharacteristic]];
//serviceTwo初始化并加入一个characteristics
CBMutableService *serviceTwo = [[CBMutableService alloc]initWithType:[CBUUID UUIDWithString:ServiceUUID2] primary:YES];
[serviceTwo setCharacteristics:@[readCharacteristic]];
//添加后就会调用代理的
- (void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error
[peripheralManager addService:serviceOne];
[peripheralManager addService:serviceTwo];
}
3.外设管理者相关的代理方法介绍
//perihpheral添加了service就调用此方法
- (void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error{
if (!error) {
//两次都添加完成后才去发送广播
//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
//开始发送广播
[peripheralManager startAdvertising:@{
CBAdvertisementDataServiceUUIDsKey : @[[CBUUID UUIDWithString:ServiceUUID1],[CBUUID UUIDWithString:ServiceUUID2]],
CBAdvertisementDataLocalNameKey : LocalNameKey
}
];
}
}
//peripheral开始发送advertising
- (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral error:(NSError *)error{
//在这里做一些发送广播时需要的记录或者动作。
}
//This method is invoked when a central configurescharacteristicto notify or indicate. * It should be used as a cue to start sending updates as the characteristic value changes.
//当特性的值发生改变就会调用这个方法
//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（这里就是最主要的发送数据的方法）
timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(sendDate:) userInfo:characteristic repeats:YES];
}
//发送数据，发送当前时间的秒数（这里自己定制）
-(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];
}
}
至此蓝牙的整个连接发送数据的过程也就完成了。苹果的文档中也介绍的很清楚。如果你觉得某种情况需要操作但是本文没有写到的。可以看看苹果的文档。也许你会发现更多利用起来很方便的方法。
学习新知识最好站在巨人的肩膀上。这样可以少走弯路。感谢那些大公无私的为大家提供学习知识的大牛。你觉得挺不错可以给个喜欢哟。动动手指关注我也是可以的，做个好基友也是可以的，玩个lol也是可以的，做人呢最重要是开心。。。哈哈哈哈