蓝牙开发<coreBluetooth/CoreBluetooth.h>

/*
 建立中心设备
 扫描外设（Discover Peripheral）
 连接外设（Connect Peripheral）
 扫描外设中的服务和特征（Discover Services And Charateristics）
 利用特征与外设做数据交互（Explore And Interact）
 断开连接（Disconnect）
 */

#import "ViewController.h"
#import <coreBluetooth/CoreBluetooth.h>

@interface ViewController ()<CBCentralManagerDelegate, CBPeripheralDelegate>

@property (nonatomic, strong) CBCentralManager *mgr;
/** 发现的外设数组*/
@property (nonatomic, strong) NSMutableArray *peripheralArray;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.建立中心设备
    // queque:如果说你传空，在主队列
    self.mgr = [[CBCentralManager alloc] initWithDelegate:self queue:nil];

    // 2.扫描外设

}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];

    // 最后一步，断开连接
    [self.mgr stopScan];
}

#pragma CBCentralManagerDelegate
/*
state:
CBManagerStateUnknown = 0, 未知
CBManagerStateResetting, 重置
CBManagerStateUnsupported, 不支持
CBManagerStateUnauthorized, 未经授权
CBManagerStatePoweredOff, 没有启动
CBManagerStatePoweredOn, 开启
 */
- (void)centralManagerDidUpdateState:(CBCentralManager *)central {

    NSLog(@"state = %zd", central.state);
    // 蓝牙开启
    if (central.state == CBManagerStateUnknown) {

        NSLog(@"未知的蓝牙");
    }
    if (central.state == CBManagerStatePoweredOn) {

        // 2.扫描外设
        [self.mgr scanForPeripheralsWithServices:nil options:nil];
    }
}

/**
 3.连接外设（Connect Peripheral）
 @param peripheral 外设
 @param advertisementData 相关的二进制数据
 @param RSSI 信号强度
 */
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary<NSString *,id> *)advertisementData RSSI:(NSNumber *)RSSI {

    // 1.记录外设，必须要有数组进来行存储
    if ([self.peripheralArray containsObject:peripheral]) {

        [self.peripheralArray addObject:peripheral];
    }
    // 2.隐藏步骤，tableview表格列表（省略了）
    // 3.连接外围设备
    [self.mgr connectPeripheral:peripheral options:nil];
    // 4.设置外设的代理
    peripheral.delegate = self;

}

// 连接到外设之后，会调用这个代理方法
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {

    // 扫描服务
    // 传nil代表扫描所有服务
    [peripheral discoverServices:nil];

}

#pragma CBPeripheralDelegate
// 外设扫描里面的服务
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {

    // 获取外设的服务
    for (CBService *service in peripheral.services) {

        if ([service.UUID.UUIDString isEqualToString:@""]) {
            // uuid一致，那就开始扫描特征
            [peripheral discoverCharacteristics:nil forService:service];

        }
    }
}

// 当发现到特征的时候会调用
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error {

    //
    for (CBCharacteristic *characteristic in service.characteristics) {

        if ([characteristic.UUID.UUIDString isEqualToString:@""]) {

//            [peripheral readValueForDescriptor:<#(nonnull CBDescriptor *)#>];

//            [peripheral writeValue:<#(nonnull NSData *)#> forDescriptor:<#(nonnull CBDescriptor *)#>];
        }
    }
}

- (NSMutableArray *)peripheralArray {

    if (!_peripheralArray) {

        _peripheralArray = [NSMutableArray array];
    }
    return _peripheralArray;
}