CoreBluetooth框架的核心其实是两个东西,peripheral和central, 可以理解成外设和中心。
图中两组api分别对应不同的业务场景,左侧叫做中心模式,就是以你的app作为中心,连接其他的外设的场景,而右侧称为外设模式,使用手机作为外设别其他中心设备操作的场景
image关于蓝牙开发的一些重要的理论概念:
1、服务(services):蓝牙外设对外广播的时候一定会有一个服务,有些时候也可以是有多个服务,服务下面包含一些特性,服务可以理解成一个模块的窗口;
2、特征(characteristic):特征存在于服务下面的,一个服务下面可以有多个特征,特征可以理解成具体实现功能的窗口,一般的特性都会有value,也就是特征值,是特征和外界交互的最小单位;
3、UUID:蓝牙上的唯一标示符,为了区分不同设备、服务及特征,就用UUID来表示。
CBCentralMannager 中心模式
以手机(app)作为中心,连接其他外设的场景。详细流程如下:
步骤1.建立一个Central Manager实例进行蓝牙管理
步骤2.搜索外围设备
步骤3.连接外围设备
步骤4.获得外围设备的服务
步骤5.获得服务的特征
步奏6.从外围设备读数据(直接读取和订阅两种方法)
步骤7.给外围设备发送数据
#import "ViewController.h"
#import
#define kPeripheralName @"Kenshin Cui's Device" //外围设备名称
#define kServiceUUID @"C4FB2349-72FE-4CA2-94D6-1F3CB16331EE" //服务的UUID
#define kCharacteristicUUID @"6A3E4B28-522D-4B3B-82A9-D5E2004534FC" //特征的UUID
@interface ViewController ()
@property (strong,nonatomic) CBPeripheralManager *peripheralManager;//外围设备管理器
@property (strong,nonatomic) NSMutableArray *centralM;//订阅此外围设备特征的中心设备
@property (strong,nonatomic) CBMutableCharacteristic *characteristicM;//特征
@property (weak, nonatomic) IBOutlet UITextView *log; //日志记录
@end
@implementation ViewController
#pragma mark - 控制器视图事件
- (void)viewDidLoad {
[super viewDidLoad];
}
#pragma mark - UI事件
- (IBAction)startClick:(UIBarButtonItem *)sender {
//创建中心设备管理器并设置当前控制器视图为代理
_centralManager=[[CBCentralManager alloc]initWithDelegate:self queue:nil];
}
#pragma mark - CBCentralManager代理方法
//中心服务器状态更新后
-(void)centralManagerDidUpdateState:(CBCentralManager *)central{
switch (central.state) {
case CBPeripheralManagerStatePoweredOn:
NSLog(@"BLE已打开.");
[self writeToLog:@"BLE已打开."];
//扫描外围设备
// [central scanForPeripheralsWithServices:@[[CBUUID UUIDWithString:kServiceUUID]] options:@{CBCentralManagerScanOptionAllowDuplicatesKey:@YES}];
[central scanForPeripheralsWithServices:nil options:@{CBCentralManagerScanOptionAllowDuplicatesKey:@YES}];
break;
default:
NSLog(@"此设备不支持BLE或未打开蓝牙功能,无法作为外围设备.");
[self writeToLog:@"此设备不支持BLE或未打开蓝牙功能,无法作为外围设备."];
break;
}
}
/**
* 发现外围设备
*
* @param central 中心设备
* @param peripheral 外围设备
* @param advertisementData 特征数据
* @param RSSI 信号质量(信号强度)
*/
-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{
NSLog(@"发现外围设备...");
[self writeToLog:@"发现外围设备..."];
//停止扫描
[self.centralManager stopScan];
//连接外围设备
if (peripheral) {
//添加保存外围设备,注意如果这里不保存外围设备(或者说peripheral没有一个强引用,无法到达连接成功(或失败)的代理方法,因为在此方法调用完就会被销毁
if(![self.peripherals containsObject:peripheral]){
[self.peripherals addObject:peripheral];
}
NSLog(@"开始连接外围设备...");
[self writeToLog:@"开始连接外围设备..."];
[self.centralManager connectPeripheral:peripheral options:nil];
}
}
//连接到外围设备
-(void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{
NSLog(@"连接外围设备成功!");
[self writeToLog:@"连接外围设备成功!"];
//设置外围设备的代理为当前视图控制器
peripheral.delegate=self;
//外围设备开始寻找服务
[peripheral discoverServices:@[[CBUUID UUIDWithString:kServiceUUID]]];
}
//连接外围设备失败
-(void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error{
NSLog(@"连接外围设备失败!");
[self writeToLog:@"连接外围设备失败!"];
}
#pragma mark - CBPeripheral 代理方法
//外围设备寻找到服务后
-(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{
NSLog(@"已发现可用服务...");
[self writeToLog:@"已发现可用服务..."];
if(error){
NSLog(@"外围设备寻找服务过程中发生错误,错误信息:%@",error.localizedDescription);
[self writeToLog:[NSString stringWithFormat:@"外围设备寻找服务过程中发生错误,错误信息:%@",error.localizedDescription]];
}
//遍历查找到的服务
CBUUID *serviceUUID=[CBUUID UUIDWithString:kServiceUUID];
CBUUID *characteristicUUID=[CBUUID UUIDWithString:kCharacteristicUUID];
for (CBService *service in peripheral.services) {
if([service.UUID isEqual:serviceUUID]){
//外围设备查找指定服务中的特征
[peripheral discoverCharacteristics:@[characteristicUUID] forService:service];
}
}
}
//外围设备寻找到特征后
-(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{
NSLog(@"已发现可用特征...");
[self writeToLog:@"已发现可用特征..."];
if (error) {
NSLog(@"外围设备寻找特征过程中发生错误,错误信息:%@",error.localizedDescription);
[self writeToLog:[NSString stringWithFormat:@"外围设备寻找特征过程中发生错误,错误信息:%@",error.localizedDescription]];
}
//遍历服务中的特征
CBUUID *serviceUUID=[CBUUID UUIDWithString:kServiceUUID];
CBUUID *characteristicUUID=[CBUUID UUIDWithString:kCharacteristicUUID];
if ([service.UUID isEqual:serviceUUID]) {
for (CBCharacteristic *characteristic in service.characteristics) {
if ([characteristic.UUID isEqual:characteristicUUID]) {
//情景一:通知
/*找到特征后设置外围设备为已通知状态(订阅特征):
*1.调用此方法会触发代理方法:-(void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
*2.调用此方法会触发外围设备的订阅代理方法
*/
[peripheral setNotifyValue:YES forCharacteristic:characteristic];
//情景二:读取
// [peripheral readValueForCharacteristic:characteristic];
// if(characteristic.value){
// NSString *value=[[NSString alloc]initWithData:characteristic.value encoding:NSUTF8StringEncoding];
// NSLog(@"读取到特征值:%@",value);
// }
}
}
}
}
//特征值被更新后
-(void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
NSLog(@"收到特征更新通知...");
[self writeToLog:@"收到特征更新通知..."];
if (error) {
NSLog(@"更新通知状态时发生错误,错误信息:%@",error.localizedDescription);
}
//给特征值设置新的值
CBUUID *characteristicUUID=[CBUUID UUIDWithString:kCharacteristicUUID];
if ([characteristic.UUID isEqual:characteristicUUID]) {
if (characteristic.isNotifying) {
if (characteristic.properties==CBCharacteristicPropertyNotify) {
NSLog(@"已订阅特征通知.");
[self writeToLog:@"已订阅特征通知."];
return;
}else if (characteristic.properties ==CBCharacteristicPropertyRead) {
//从外围设备读取新值,调用此方法会触发代理方法:-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
[peripheral readValueForCharacteristic:characteristic];
}
}else{
NSLog(@"停止已停止.");
[self writeToLog:@"停止已停止."];
//取消连接
[self.centralManager cancelPeripheralConnection:peripheral];
}
}
}
//更新特征值后(调用readValueForCharacteristic:方法或者外围设备在订阅后更新特征值都会调用此代理方法)
-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
if (error) {
NSLog(@"更新特征值时发生错误,错误信息:%@",error.localizedDescription);
[self writeToLog:[NSString stringWithFormat:@"更新特征值时发生错误,错误信息:%@",error.localizedDescription]];
return;
}
if (characteristic.value) {
NSString *value=[[NSString alloc]initWithData:characteristic.value encoding:NSUTF8StringEncoding];
NSLog(@"读取到特征值:%@",value);
[self writeToLog:[NSString stringWithFormat:@"读取到特征值:%@",value]];
}else{
NSLog(@"未发现特征值.");
[self writeToLog:@"未发现特征值."];
}
}
#pragma mark - 属性
-(NSMutableArray *)peripherals{
if(!_peripherals){
_peripherals=[NSMutableArray array];
}
return _peripherals;
}
#pragma mark - 私有方法
/**
* 记录日志
*
* @param info 日志信息
*/
-(void)writeToLog:(NSString *)info{
self.log.text=[NSString stringWithFormat:@"%@\r\n%@",self.log.text,info];
}
@end
CBPeripheralManager 外设模式
使用手机作为外设连接其他中心设备操作的场景。
PS:因为苹果设备的安全性和封闭性,苹果设备不能通过与其他设备蓝牙链接进行文件传输等功能,所以在iOS与蓝牙开发的编程中是CBCentralMannager 中心模式编程居多.
1 建立外设角色
2 设置本地外设的服务和特征
3 发布外设和特征
4 广播服务
5 响应中心的读写请求
6 发送更新的特征值,订阅中心
#import "ViewController.h"
#import
#define kServiceUUID @"C4FB2349-72FE-4CA2-94D6-1F3CB16331EE" //服务的UUID
#define kCharacteristicUUID @"6A3E4B28-522D-4B3B-82A9-D5E2004534FC" //特征的UUID
@interface ViewController ()
@property (strong,nonatomic) CBCentralManager *centralManager;//中心设备管理器
@property (strong,nonatomic) NSMutableArray *peripherals;//连接的外围设备
@property (weak, nonatomic) IBOutlet UITextView *log;//日志记录
@end
@implementation ViewController
#pragma mark - 视图控制器方法
- (void)viewDidLoad {
[super viewDidLoad];
}
#pragma mark - UI事件
//创建外围设备
- (IBAction)startClick:(UIBarButtonItem *)sender {
_peripheralManager=[[CBPeripheralManager alloc]initWithDelegate:self queue:nil];
}
//更新数据
- (IBAction)transferClick:(UIBarButtonItem *)sender {
[self updateCharacteristicValue];
}
#pragma mark - CBPeripheralManager代理方法
//外围设备状态发生变化后调用
-(void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral{
switch (peripheral.state) {
case CBPeripheralManagerStatePoweredOn:
NSLog(@"BLE已打开.");
[self writeToLog:@"BLE已打开."];
//添加服务
[self setupService];
break;
default:
NSLog(@"此设备不支持BLE或未打开蓝牙功能,无法作为外围设备.");
[self writeToLog:@"此设备不支持BLE或未打开蓝牙功能,无法作为外围设备."];
break;
}
}
//外围设备添加服务后调用
-(void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(NSError *)error{
if (error) {
NSLog(@"向外围设备添加服务失败,错误详情:%@",error.localizedDescription);
[self writeToLog:[NSString stringWithFormat:@"向外围设备添加服务失败,错误详情:%@",error.localizedDescription]];
return;
}
//添加服务后开始广播
NSDictionary *dic=@{CBAdvertisementDataLocalNameKey:kPeripheralName};//广播设置
[self.peripheralManager startAdvertising:dic];//开始广播
NSLog(@"向外围设备添加了服务并开始广播...");
[self writeToLog:@"向外围设备添加了服务并开始广播..."];
}
-(void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral error:(NSError *)error{
if (error) {
NSLog(@"启动广播过程中发生错误,错误信息:%@",error.localizedDescription);
[self writeToLog:[NSString stringWithFormat:@"启动广播过程中发生错误,错误信息:%@",error.localizedDescription]];
return;
}
NSLog(@"启动广播...");
[self writeToLog:@"启动广播..."];
}
//订阅特征
-(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didSubscribeToCharacteristic:(CBCharacteristic *)characteristic{
NSLog(@"中心设备:%@ 已订阅特征:%@.",central,characteristic);
[self writeToLog:[NSString stringWithFormat:@"中心设备:%@ 已订阅特征:%@.",central.identifier.UUIDString,characteristic.UUID]];
//发现中心设备并存储
if (![self.centralM containsObject:central]) {
[self.centralM addObject:central];
}
/*中心设备订阅成功后外围设备可以更新特征值发送到中心设备,一旦更新特征值将会触发中心设备的代理方法:
-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
*/
// [self updateCharacteristicValue];
}
//取消订阅特征
-(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didUnsubscribeFromCharacteristic:(CBCharacteristic *)characteristic{
NSLog(@"didUnsubscribeFromCharacteristic");
}
-(void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveWriteRequests:(CBATTRequest *)request{
NSLog(@"didReceiveWriteRequests");
}
-(void)peripheralManager:(CBPeripheralManager *)peripheral willRestoreState:(NSDictionary *)dict{
NSLog(@"willRestoreState");
}
#pragma mark -属性
-(NSMutableArray *)centralM{
if (!_centralM) {
_centralM=[NSMutableArray array];
}
return _centralM;
}
#pragma mark - 私有方法
//创建特征、服务并添加服务到外围设备
-(void)setupService{
/*1.创建特征*/
//创建特征的UUID对象
CBUUID *characteristicUUID=[CBUUID UUIDWithString:kCharacteristicUUID];
//特征值
// NSString *valueStr=kPeripheralName;
// NSData *value=[valueStr dataUsingEncoding:NSUTF8StringEncoding];
//创建特征
/** 参数
* uuid:特征标识
* properties:特征的属性,例如:可通知、可写、可读等
* value:特征值
* permissions:特征的权限
*/
CBMutableCharacteristic *characteristicM=[[CBMutableCharacteristic alloc]initWithType:characteristicUUID properties:CBCharacteristicPropertyNotify value:nil permissions:CBAttributePermissionsReadable];
self.characteristicM=characteristicM;
// CBMutableCharacteristic *characteristicM=[[CBMutableCharacteristic alloc]initWithType:characteristicUUID properties:CBCharacteristicPropertyRead value:nil permissions:CBAttributePermissionsReadable];
// characteristicM.value=value;
/*创建服务并且设置特征*/
//创建服务UUID对象
CBUUID *serviceUUID=[CBUUID UUIDWithString:kServiceUUID];
//创建服务
CBMutableService *serviceM=[[CBMutableService alloc]initWithType:serviceUUID primary:YES];
//设置服务的特征
[serviceM setCharacteristics:@[characteristicM]];
/*将服务添加到外围设备*/
[self.peripheralManager addService:serviceM];
}
//更新特征值
-(void)updateCharacteristicValue{
//特征值
NSString *valueStr=[NSString stringWithFormat:@"%@ --%@",kPeripheralName,[NSDate date]];
NSData *value=[valueStr dataUsingEncoding:NSUTF8StringEncoding];
//更新特征值
[self.peripheralManager updateValue:value forCharacteristic:self.characteristicM onSubscribedCentrals:nil];
[self writeToLog:[NSString stringWithFormat:@"更新特征值:%@",valueStr]];
}
/**
* 记录日志
*
* @param info 日志信息
*/
-(void)writeToLog:(NSString *)info{
self.log.text=[NSString stringWithFormat:@"%@\r\n%@",self.log.text,info];
}
@end
蓝牙连接发送数据的流程图
16a2962d7ce67281.png遇到的坑
截屏2019-10-2315.57.54.png所以得知道 设备广播的的UUID
或者用下面代码搜索蓝牙
[self.centralManager scanForPeripheralsWithServices:nil options:nil];
一般蓝牙连接失败我们会实现以下方法
// 连接失败(但不包含超时,系统没有超时处理)
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
if (error && self.delegate && [self.delegate respondsToSelector:@selector(centralTool:connectFailure:)]) {
[self.delegate centralTool:self connectFailure:error];
}
}
- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
{
[self autoConnect];
}
但是当广播设备的蓝牙断开再想重连的话还要实现下面这个方法
- (void)peripheral:(CBPeripheral *)peripheral didModifyServices:(NSArray<CBService *> *)invalidatedServices{
[self.centralManager connectPeripheral:peripheral options:nil];
// 注意保留 Peripheral 的引用
self.lastConnectedPeripheral = peripheral;
[self startTimer];
}
只有这样才能实现断开蓝牙重开蓝牙秒连
另外,有时候要提高搜索效率的话,可以过滤蓝牙的名字
NSString *name = peripheral.name;
if (name.length == 0) {
return;
}
NSLog(@"name === %@",name);
NSString *string = [NSString stringWithFormat:@"已发现 peripheral: %@ rssi: %@, UUID: %@ advertisementData: %@ ", peripheral, RSSI, peripheral.identifier, advertisementData];
NSLog(@"string == %@",string);
if ([name rangeOfString:@"Berry"].location == NSNotFound) {
return;
}
// NSString *kCBAdvDataLocalName = [advertisementData objectForKey:CBAdvertisementDataLocalNameKey];
// if ([kCBAdvDataLocalName rangeOfString:@"Berry"].location == NSNotFound) {
// return;
// }
不过要注意 上文代码中的name 和 kCBAdvDataLocalName 是不同的
一个是蓝牙设备的名字, 一个是广播的名字
//添加服务后开始广播
//广播设置
NSDictionary *dic=@{CBAdvertisementDataLocalNameKey:MyDeviceName,CBAdvertisementDataServiceUUIDsKey:@[[CBUUID UUIDWithString:@"FFE0"]]};
//广播设置
[self.peripheralManager startAdvertising:dic];//开始广播
第一个坑中设置UUID找不到的问题就是,需要在上述代码中设置UUID
网上找的大部分资料都是关于如何设置中心设备的,外设的比较少,所以这里容易出错
不过,如果这块都设置了,对于快速精准找到目标蓝牙服务是大有裨益的,也会减少耗电量,提高响应速度等等。
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