目前在iOS中藍(lán)牙開發(fā)框架主要有以下幾種

• GameKit.framework：iOS7之前的藍(lán)牙通訊框架，從iOS7開始過(guò)期.
• MultipeerConnectivity.framework：iOS7開始引入的新的藍(lán)牙通訊開發(fā)框架岳守，用于取代GameKit。
• CoreBluetooth.framework：功能強(qiáng)大的藍(lán)牙開發(fā)框架，要求設(shè)備必須支持藍(lán)牙4.0鼓择。
• 前兩個(gè)框架使用起來(lái)比較簡(jiǎn)單兑宇，但是缺點(diǎn)也比較明顯：僅僅支持iOS設(shè)備，傳輸內(nèi)容僅限于沙盒或者照片庫(kù)中用戶選擇的文件邢隧，并且第一個(gè)框架只能在同一個(gè)應(yīng)用之間進(jìn)行傳輸（一個(gè)iOS設(shè)備安裝應(yīng)用A修档，另一個(gè)iOS設(shè)備上安裝應(yīng)用B是無(wú)法傳輸?shù)模oreBluetooth就擺脫了這些束縛府框，它不再局限于iOS設(shè)備之間進(jìn)行傳輸吱窝，你可以通過(guò)iOS設(shè)備向Android讥邻、Windows Phone以及其他安裝有藍(lán)牙4.0芯片的智能設(shè)備傳輸，因此也是目前智能家居院峡、無(wú)線支付等熱門智能設(shè)備所推崇的技術(shù)兴使。本文主要介紹CoreBluetooth的相關(guān)開發(fā)流程.

CoreBluetooth開發(fā)模式

CoreBluetooth設(shè)計(jì)類似于客戶端-服務(wù)器端的設(shè)計(jì)，peripheral和central, 可以理解成外設(shè)和中心照激。對(duì)應(yīng)他們分別有一組相關(guān)的API和類.

CoreBluetooth架構(gòu)

• 左側(cè)叫做中心模式发魄，以app作為中心，連接其他的外設(shè)的俩垃，而右側(cè)稱為外設(shè)模式励幼，使用手機(jī)作為外設(shè)別其他中心設(shè)備操作的場(chǎng)景。

• 服務(wù)和特征口柳，特征的屬性(service and characteristic):
  藍(lán)牙設(shè)備添加若干服務(wù)苹粟，服務(wù)內(nèi)添加若干特征，特征就是具體鍵值對(duì)跃闹，提供對(duì)數(shù)據(jù)的讀取和寫嵌削。藍(lán)牙中心和外設(shè)數(shù)據(jù)的交換基于服務(wù)的特征.

  
  
  外設(shè)和服務(wù)特征的關(guān)系

中心的開發(fā)

• 流程
  <pre>

1. 建立中心角色
2. 掃描外設(shè)（discover）
3. 連接外設(shè)(connect)
4. 掃描外設(shè)中的服務(wù)和特征(discover)
   • 4.1 獲取外設(shè)的services
   • 4.2 獲取外設(shè)的Characteristics,獲取Characteristics的值，獲取 Characteristics的Descriptor和Descriptor的值
5. 與外設(shè)做數(shù)據(jù)交互(explore and interact)
6. 訂閱Characteristic的通知
7. 斷開連接(disconnect)
   </pre>

• 步驟
  CoreBluetooth中不管是中心還是外設(shè)的開發(fā),均是上面的流程,通過(guò)一步步的代理回調(diào)實(shí)現(xiàn)的,按照流程跟著走,一步一步實(shí)現(xiàn)代理.
  <pre>
  //初始化
  _centralManager = [[CBCentralManager alloc] initWithDelegate:self
  queue:nil
  options:@{CBCentralManagerOptionRestoreIdentifierKey:kRestoreIdentifierKey}];
  //監(jiān)聽(tīng)中心設(shè)備狀態(tài)
  -(void)centralManagerDidUpdateState:(CBCentralManager *)central{
  if (central.state == CBCentralManagerStatePoweredOn) {
  [self writeToLogWithText:@"中心設(shè)備已打開"];
  [_centralManager scanForPeripheralsWithServices:nil options:nil];
  } //中心設(shè)備CBCentralManagerStatePoweredOn狀態(tài)下就可以開始搜索外設(shè)了
  }
  -(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary<NSString *,id> *)advertisementData RSSI:(NSNumber *)RSSI{
  //搜索到指定的外設(shè)就可以開始連接外設(shè)了
  [_centralManager connectPeripheral:peripheral options:nil];
  }
  -(void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{
  //連接成功后開始搜索服務(wù)
  [peripheral discoverServices:nil];
  }
  -(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{
  //搜索服務(wù)成功后查找指定服務(wù)中的特征
  [peripheral discoverCharacteristics:nil forService:service];
  }
  -(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(nonnull CBService *)service error:(nullable NSError *)error{
  //發(fā)現(xiàn)可用特征后,就可以進(jìn)行相應(yīng)的操作了,主要有以下三種
  //情景一：讀取
  if (characteristic.properties & CBCharacteristicPropertyRead) {
  if ([characteristic.UUID.UUIDString isEqualToString:kReadUUID]) {
  [peripheral readValueForCharacteristic:characteristic];
  if (characteristic.value) {
  NSString *value=[[NSString alloc]initWithData:characteristic.value encoding:NSUTF8StringEncoding];
  NSLog(@"讀取到特征值：%@",value);
  }
  }
  }

    //情景二：通知
    if (characteristic.properties & CBCharacteristicPropertyNotify) {
        if ([characteristic.UUID.UUIDString isEqualToString:kNotifyUUID] || [characteristic.UUID.UUIDString isEqualToString:kWriteUUID]) {
            _curCharacter = characteristic;
            [peripheral setNotifyValue:YES forCharacteristic:characteristic];
            [self writeToLogWithText:@"已訂閱特征通知"];
        }
    }
    
    //情景二：寫數(shù)據(jù)
    if (characteristic.properties & CBCharacteristicPropertyWrite) {
        if ([characteristic.UUID.UUIDString isEqualToString:kWriteUUID]) {
            [peripheral writeValue:[@"hello,外設(shè)" dataUsingEncoding:NSUTF8StringEncoding] forCharacteristic:characteristic type:CBCharacteristicWriteWithResponse];
            [self writeToLogWithText:@"寫數(shù)據(jù)給外設(shè)"];
            
            _curPeripherals = peripheral;
            _curCharacter = characteristic;
        }
    }
  

}
//根據(jù)不同的場(chǎng)景,會(huì)調(diào)用以下三個(gè)方法
-(void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(nonnull CBCharacteristic *)characteristic error:(nullable NSError *)error;
-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(nonnull CBCharacteristic *)characteristic error:(nullable NSError *)error;
-(void)peripheral:(CBPeripheral *)peripheral didWriteValueForCharacteristic:(nonnull CBCharacteristic *)characteristic error:(nullable NSError *)error;
}
</pre>

外設(shè)的開發(fā)

• 流程
  <pre>
  1. 打開peripheralManager望艺，設(shè)置peripheralManager的委托

2. 創(chuàng)建characteristics苛秕，characteristics的description 創(chuàng)建service，把characteristics添加到service中找默，再把service添加到peripheralManager中
3. 開啟廣播advertising
4. 對(duì)central的操作進(jìn)行響應(yīng)
   • 4.1 讀characteristics請(qǐng)求
   • 4.2 寫characteristics請(qǐng)求
   • 4.4 訂閱和取消訂閱characteristics
     </pre>

• 步驟
  <pre>
  //初始化
  _peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil];
  //啟動(dòng)外設(shè)
  -(void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral{
  switch (peripheral.state) {
  case CBPeripheralManagerStatePoweredOn:
  //CBPeripheralManagerStatePoweredOn下添加服務(wù)和特征
  [self setupService];
  }
  //創(chuàng)建服務(wù),特征并添加服務(wù)到外圍設(shè)備
  -(void)setupService{

  //可通知的特征
  // CBUUID *characteristicUUID = [CBUUID UUIDWithString:kNotifyUUID];
  // _characteristic = [[CBMutableCharacteristic alloc] initWithType:characteristicUUID properties:CBCharacteristicPropertyNotify value:nil permissions:CBAttributePermissionsReadable];

  //可讀寫的特征
  CBUUID *UUID2 = [CBUUID UUIDWithString:kWriteUUID];
  _characteristic = [[CBMutableCharacteristic alloc] initWithType:UUID2 properties:CBCharacteristicPropertyWrite|CBCharacteristicPropertyNotify value:nil permissions:CBAttributePermissionsWriteEncryptionRequired];
  //
  //只讀的特征
  // CBUUID *UUID3 = [CBUUID UUIDWithString:kReadUUID];
  // NSData *characteristicValue = [@"aaron才" dataUsingEncoding:NSUTF8StringEncoding];
  // _characteristic = [[CBMutableCharacteristic alloc] initWithType:UUID3 properties:CBCharacteristicPropertyRead value:characteristicValue permissions:CBAttributePermissionsReadable];

  CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID];
  _service = [[CBMutableService alloc] initWithType:serviceUUID primary:YES];
  [_service setCharacteristics:@[_characteristic]];

  [_peripheralManager addService:_service];
  }
  //添加服務(wù)后開始廣播,等待中心設(shè)備的連接
  -(void)peripheralManager:(CBPeripheralManager *)peripheral didAddService:(CBService *)service error:(nullable NSError *)error{
  NSDictionary *dict = @{CBAdvertisementDataLocalNameKey:kPeripheralName};
  [_peripheralManager startAdvertising:dict];
  [self writeToLogWithText:@"向外圍設(shè)備添加了服務(wù)"];
  }
  根據(jù)中心設(shè)備的響應(yīng),外設(shè)在代理中收到中心發(fā)來(lái)的信息,
  //訂閱特征
  -(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didSubscribeToCharacteristic:(CBCharacteristic *)characteristic;
  //取消訂閱
  -(void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didUnsubscribeFromCharacteristic:(CBCharacteristic *)characteristic;
  //中心設(shè)備讀外設(shè)數(shù)據(jù)
  -(void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveReadRequest:(CBATTRequest *)request;
  //收到中心寫來(lái)的數(shù)據(jù)
  -(void)peripheralManager:(CBPeripheralManager *)peripheral didReceiveWriteRequests:(NSArray<CBATTRequest *> *)requests;
  </pre>

UIBackgroundModes下的藍(lán)牙數(shù)據(jù)傳輸

CoreBluetooth提供了非常友好的Background支持.按一下步驟,經(jīng)過(guò)測(cè)試,app進(jìn)入后臺(tái)后,也能收到外設(shè)特征更新的值,據(jù)WWDC2013視頻介紹,就算因?yàn)閮?nèi)存緊張,app在后臺(tái)被殺掉,系統(tǒng)也會(huì)自動(dòng)幫我們重新啟動(dòng)app進(jìn)行藍(lán)牙數(shù)據(jù)傳輸,不過(guò)這個(gè)就沒(méi)測(cè)試到,不知道有沒(méi)有人做過(guò)這方便的研究.

• 設(shè)置info.plist
  

<pre>
<key>UIBackgroundModes</key>
<array>
<string>bluetooth-central</string>
<string>bluetooth-peripheral</string>
</array>
</pre>

• 初始化方式中添加``options:@{CBCentralManagerOptionRestoreIdentifierKey:kRestoreIdentifierKey}``
  

<pre>
_centralManager = [[CBCentralManager alloc] initWithDelegate:self
queue:nil
options:@{CBCentralManagerOptionRestoreIdentifierKey:kRestoreIdentifierKey}];
</pre>

<pre>

• (void)centralManager:(CBCentralManager *)central willRestoreState:(NSDictionary<NSString *,id> *)dict{

// NSArray *scanServices = dict[CBCentralManagerRestoredStateScanServicesKey];
// NSArray *scanOptions = dict[CBCentralManagerRestoredStateScanOptionsKey];

NSArray *peripherals = dict[CBCentralManagerRestoredStatePeripheralsKey];
for (CBPeripheral *peripheral in peripherals) {
    [self.peripherals addObject:peripheral];
    peripheral.delegate = self;
}

}
</pre>

<pre>

• (void)centralManagerDidUpdateState:(CBCentralManager *)central{

  if (central.state == CBCentralManagerStatePoweredOn) {
  [self writeToLogWithText:@"中心設(shè)備已打開"];
  [_centralManager scanForPeripheralsWithServices:nil options:nil];

    //03,檢查是否restore connected peripherals
    for (CBPeripheral *peripheral in _peripherals) {
        if (peripheral.state == CBPeripheralStateConnected) {
            NSUInteger serviceIdx = [peripheral.services indexOfObjectPassingTest:^BOOL(CBService * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
                return [obj.UUID isEqual:kServiceUUID];
            }];
            
            if (serviceIdx == NSNotFound) {
                [peripheral discoverServices:@[kServiceUUID]];
                continue;
            }
            
            CBService *service = peripheral.services[serviceIdx];
            NSUInteger charIdx = [service.characteristics indexOfObjectPassingTest:^BOOL(CBCharacteristic * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
                return [obj.UUID isEqual:kNotifyUUID];
            }];
            
            if (charIdx == NSNotFound) {
                [peripheral discoverCharacteristics:@[kNotifyUUID] forService:service];
                continue;
            }
            
            CBCharacteristic *characteristic = service.characteristics[charIdx];
            if (!characteristic.isNotifying) {
                [peripheral setNotifyValue:YES forCharacteristic:characteristic];
            }
        }
    }
  

  }else{
  [_peripherals removeAllObjects];
  }
  }
  </pre>

<pre>

• (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  // Override point for customization after application launch.

  NSArray *peripheralManagerIdentifiers = launchOptions[UIApplicationLaunchOptionsBluetoothPeripheralsKey];
  NSArray *centraManagerIdentifiers = launchOptions[UIApplicationLaunchOptionsBluetoothCentralsKey];

  for (NSString *identifier in centraManagerIdentifiers) {
  if ([identifier isEqualToString:kRestoreIdentifierKey]) {

    }
  

  }

  return YES;
  }
  </pre>

Demo

不動(dòng)手寫代碼的學(xué)框架都是耍流氓,為了更好的學(xué)習(xí),我也是自己都敲了一遍代碼,前文中的三種場(chǎng)景以及后臺(tái)模式都實(shí)現(xiàn)了,可以實(shí)現(xiàn)中心設(shè)備和外設(shè)之前的訂閱特征,讀寫數(shù)據(jù)等功能.希望大家都交流.下面是傳送門以及界面展示??
github傳送門 CoreBluetoothDemo

主界面

![中心設(shè)備]IMG_3660.PNG](http://upload-images.jianshu.io/upload_images/1093584-e66b42d6c1c7133f.PNG?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

外設(shè)