iOS蓝牙BLE4.0通信功能

概述

iOS蓝牙BLE4.0通信功能，最近刚学的苹果，为了实现蓝牙门锁的项目，找了一天学习了下蓝牙的原理，亲手测试了一次蓝牙的通信功能，结果成功了，那么就把我学习的东西分享一下。

详细

代码下载：http://www.demodashi.com/demo/10635.html

一、蓝牙常见名称和缩写

BLE：(Bluetooth low energy)蓝牙4.0设备因为低耗电
BLE：(Bluetooth low energy)蓝牙4.0设备因为低耗电
Central：中心设备，发起蓝牙连接的设备(一般是指手机)
Peripheral：外设，被蓝牙连接的设备(一般是运动手环)
Service and Characteristic：服务和特征，每个设备会提供服务和特征，类似于服务端的API，但是结构不同，每个设备会有很多服务，每个服务中包含很多特征，这些特征的权限一般分为读(read)，写(write)，通知(notify)几种，就是我们连接设备后具体需要操作的内容
Description：描述，每个Characteristic可以对应一个或者多个Description用于描述Characteristic的信息或属性

二、蓝牙基础知识

1、CoreBluetooth框架的核心其实是俩东西

Peripheral
Central

2、这两组api分别对应不同的业务常见

左侧叫中心模式，就是以你的app作为中心，连接其他的外设的场景
右侧称为外设模式，使用外设连接其他中心设备操作的场景

3、服务和特征(service and characteristic)

每个设备都会有1个or多个服务
每个服务里都会有1个or多个特征
特征就是具体键值对，提供数据的地方
每个特征属性分为：读，写，通知等等

外设，服务，特征的关系

三、BLE中心模式流程

1、建立中心角色

2、扫描外设(Discover Peripheral)

3、连接外设(Connect Peripheral)

4、扫描外设中的服务和特征(Discover Services And Characteristics)

4.1 获取外设的services

4.2 获取外设的Characteristics，获取characteristics的值

4.3 获取Characteristics的Descriptor和Descriptor的值

5、利用特征与外设做数据交互

6、订阅Characteristic的通知

7、断开连接(Disconnect)

四、准备工作

1、一台苹果设备，进行真机测试

2、一个蓝牙模块或者外设

五、程序实现

项目代码截图：

以下是实现的过程：

1、导入依赖库、声明委托、定义变量

#import "ViewController.h"
#import <CoreBluetooth/CoreBluetooth.h>
 
#define mBLEName @"ZJ2"
 
@interface ViewController () <CBCentralManagerDelegate, CBPeripheralDelegate>
//手机设备
@property (nonatomic, strong) CBCentralManager *mCentral;
//外设设备
@property (nonatomic, strong) CBPeripheral *mPeripheral;
//特征值
@property (nonatomic, strong) CBCharacteristic *mCharacteristic;
//服务
@property (nonatomic, strong) CBService *mService;
//描述
@property (nonatomic, strong) CBDescriptor *mDescriptor;
 
@end

2、程序开始时初始化设备

- (CBCentralManager *)mCentral
{
    if (!_mCentral) {
        _mCentral = [[CBCentralManager alloc] initWithDelegate:self
                                                         queue:dispatch_get_main_queue()
                                                       options:nil];
    }
    return _mCentral;
}
 
- (void)viewDidLoad
{
    [super viewDidLoad];
     
    //中心管理者初始化
    [self mCentral];
}

3、当程序退出时，记得断开连接

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
     
    // 停止扫描
    if([self.mCentral isScanning]){
        NSLog(@"stopScan");
        [self.mCentral stopScan];
    }
    //停止连接
    if(nil != self.mPeripheral && self.mPeripheral.state == CBPeripheralStateConnecting){
        NSLog(@"cancelPeripheralConnection");
        [self.mCentral cancelPeripheralConnection:self.mPeripheral];
    }
}

4、扫描外设

//只要中心管理者初始化,就会触发此代理方法
- (void)centralManagerDidUpdateState:(CBCentralManager *)central
{
    switch (central.state) {
        case CBManagerStateUnknown:
            NSLog(@"CBManagerStateUnknown");
            break;
        case CBManagerStateResetting:
            NSLog(@"CBManagerStateResetting");
            break;
        case CBManagerStateUnsupported:
            NSLog(@"CBManagerStateUnsupported");
            break;
        case CBManagerStateUnauthorized:
            NSLog(@"CBManagerStateUnauthorized");
            break;
        case CBManagerStatePoweredOff:
            NSLog(@"CBManagerStatePoweredOff");
            break;
        case CBManagerStatePoweredOn:
        {
            NSLog(@"CBManagerStatePoweredOn");
            //搜索外设
            [self.mCentral scanForPeripheralsWithServices:nil // 通过某些服务筛选外设
                                                  options:nil]; // dict,条件
        }
            break;
        default:
            break;
    }
}

5、连接外设

//发现外设后调用的方法
- (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
{
    NSLog(@"搜索到设备名：%@，设备ID：%@",peripheral.name,peripheral.identifier);
    //(ABS(RSSI.integerValue) > 35)
    //发现完之后就是进行连接
    if([peripheral.name isEqualToString:mBLEName]){
        self.mPeripheral = peripheral;
        self.mPeripheral.delegate = self;
        [self.mCentral connectPeripheral:peripheral options:nil];
    }
}

6、获取服务

//中心管理者连接外设成功
- (void)centralManager:(CBCentralManager *)central // 中心管理者
  didConnectPeripheral:(CBPeripheral *)peripheral // 外设
{
    NSLog(@"设备连接成功，设备名：%@", peripheral.name);
    //7、外设发现服务,传nil代表不过滤
    [self.mPeripheral discoverServices:nil];
}
 
// 外设连接失败
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
{
    NSLog(@"设备连接失败，设备名：%@", peripheral.name);
}
 
// 丢失连接
- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
{
    NSLog(@"设备丢失连接，设备名：%@", peripheral.name);
}

7、获取服务中的特征

//发现外设的服务后调用的方法
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
{
    // 是否获取失败
    if (error) {
        NSLog(@"设备获取服务失败，设备名：%@", peripheral.name);
        return;
    }
    for (CBService *service in peripheral.services) {
        self.mService = service;
        NSLog(@"设备获取服务成功，服务名：%@，服务UUID：%@，服务数量：%lu",service,service.UUID,peripheral.services.count);
        //外设发现特征
        [peripheral discoverCharacteristics:nil forService:service];
    }
}

8、获取特征中的值和描述

//从服务中发现外设特征的时候调用的代理方法
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
{
    if(error){
        NSLog(@"设备获取特征失败，设备名：%@", peripheral.name);
        return;
    }
    /**
    CBCharacteristicPropertyRead                                                    = 0x02,
    CBCharacteristicPropertyWriteWithoutResponse                                    = 0x04,
    CBCharacteristicPropertyWrite                                                   = 0x08,
    CBCharacteristicPropertyNotify                                                  = 0x10,
     */
    for (CBCharacteristic *cha in service.characteristics) {
        if(cha.properties & CBCharacteristicPropertyWrite){
            NSLog(@"CBCharacteristicPropertyWrite");
            NSLog(@"%lu",cha.properties & CBCharacteristicPropertyWrite);
            self.mCharacteristic = cha;
        }else if(cha.properties & CBCharacteristicPropertyWriteWithoutResponse){
            NSLog(@"CBCharacteristicPropertyWriteWithoutResponse");
        }else if(cha.properties & CBCharacteristicPropertyRead){
            NSLog(@"CBCharacteristicPropertyRead");
        }else if(cha.properties & CBCharacteristicPropertyNotify){
            NSLog(@"CBCharacteristicPropertyNotify");
        }else if(cha.properties & CBCharacteristicPropertyIndicate){
            NSLog(@"CBCharacteristicPropertyIndicate");
        }
        NSLog(@"设备获取特征成功，服务名：%@，特征值名：%@，特征UUID：%@，特征数量：%lu",service,cha,cha.UUID,service.characteristics.count);
        //获取特征对应的描述 会回调didDiscoverDescriptorsForCharacteristic
        [peripheral discoverDescriptorsForCharacteristic:cha];
        //获取特征的值 会回调didUpdateValueForCharacteristic
        [peripheral readValueForCharacteristic:cha];
    }
    if(nil != self.mCharacteristic){
        //打开外设的通知，否则无法接受数据
        [peripheral setNotifyValue:YES forCharacteristic:self.mCharacteristic];
    }
}

9、读取特征中的值和描述

//更新特征值的时候调用，可以理解为获取蓝牙发回的数据
- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
{
    NSString *value = [[NSString alloc] initWithData:characteristic.value encoding:NSASCIIStringEncoding];
    NSLog(@"特征名：%@，特征值：%@",characteristic,value);
     
    if([value isEqualToString:@"open"]){
         
    }else if([value isEqualToString:@"close"]){
         
    }
}

10、状态改变和发现描述

//通知状态改变时调用
-(void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
    if(error){
        NSLog(@"特征名：%@，改变通知状态失败",characteristic);
    }
    NSLog(@"特征名：%@，改变了通知状态",characteristic);
}
 
//发现外设的特征的描述数组
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(nonnull CBCharacteristic *)characteristic error:(nullable NSError *)error
{
    if(error){
        NSLog(@"设备获取描述失败，设备名：%@", peripheral.name);
        return;
    }
    for (CBDescriptor *descriptor in characteristic.descriptors) {
        self.mDescriptor = descriptor;
        [peripheral readValueForDescriptor:descriptor];
        NSLog(@"设备获取描述成功，描述名：%@",descriptor);
    }
}

11、发送数据

//发送数据
-(void)sendDataToBLE:(NSString *)data{
    NSData* myData = [data dataUsingEncoding:NSUTF8StringEncoding];
    [self.mPeripheral writeValue:myData // 写入的数据
               forCharacteristic:self.mCharacteristic // 写给哪个特征
                            type:CBCharacteristicWriteWithResponse];// 通过此响应记录是否成功写入
}
 
-(void)peripheral:(CBPeripheral *)peripheral didWriteValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
    NSLog(@"数据发送成功");
}