iOS CoreBluetooth 虚拟外设多重通知

Question

我正在开发一个 iOS 应用程序，我需要将超过 20 个字节的数据发送到蓝牙 LE 中心。我已经设置了一个外设管理器，我一个接一个地发送 20 个字节的每个 "packet"。我只在 peripheralManager.updatevalue returns 为真时发送下一个数据包（如果 updateValue returns 为假，我会在调用 peripheralManagerIsReadyToUpdateSubscribers 后重试）。大多数情况下这是有效的，但是大约 20% 的时间发送的数据不正确。

我有三个包裹。大多数情况下，中央接收 A，然后接收 B，然后接收 C，但有时中央接收 B，然后接收 B，然后再接收 C，或者接收 A，然后接收 C，然后再接收 C。

它总是发送三个通知，但是值不正确。

万一重要：

特性的值存储在 BLECharacteristic 个对象的实例中

@objc public class BLECharacteristic: CBMutableCharacteristic{
    public var dynamicValue: Data?
    public override init(type UUID: CBUUID, properties: CBCharacteristicProperties, value: Data?, permissions: CBAttributePermissions){
        super.init(type: UUID, properties: properties, value: nil, permissions: permissions)
        self.dynamicValue = value
    }
    public convenience init(characteristic: CBCharacteristic){
        self.init(type: characteristic.uuid, properties: characteristic.properties, value: characteristic.value, permissions: CBAttributePermissions.readable)
    }
}

当调用 peripheralManagerIsReadyToUpdateSubscribers 后 "buffered" 发送通知时，信息存储在 DelayedNotification 对象中。

@objc public class DelayedNotification: NSObject{
    private(set) var valueToNotify: Data
    private(set) var characteristic: BLECharacteristic
    private(set) var devicesToNotify: [CBCentral]?

    @objc public init(_ data: Data, _ char: BLECharacteristic, _ devsNotify: [CBCentral]?){
        valueToNotify = data
        characteristic = char
        devicesToNotify = devsNotify
    }
}

创建对象时：

var valueToSend: Data
if(characteristic.dynamicValue == nil){
    valueToSend = Data()
}else{
    valueToSend = characteristic.dynamicValue!
}

buffer.append(DelayedNotification(valueToSend, characteristic, devicesToNotify))

编辑：更多代码

private func notifyDevices(_ characteristic: BLECharacteristic){
    DispatchQueue.main.async {
        var valueToSend: Data
        if(characteristic.dynamicValue == nil){
            valueToSend = Data()
        }else{
            valueToSend = Data(characteristic.dynamicValue!)
        }

        self.notificationLock.wait()
        self.notBuffer.append(DelayedNotification(valueToSend, characteristic, nil))
        self.notificationLock.signal()

        self.processNotificationBuffer()
    }
}

private func processNotificationBuffer(){
    DispatchQueue.main.async{
        self.notificationLock.wait()

        for notification in self.notBuffer{
            let res = self.peripheralManager.updateValue(Data(notification.valueToNotify), for: notification.characteristic, onSubscribedCentrals: notification.devicesToNotify)
            if(res){
                NSLog("Sent: " + String(data: notification.valueToNotify, encoding: .utf8)!) // This is always printed in the right order
                notificationSent()
                self.notBuffer.remove(at: self.notBuffer.index(of: notification)!)
            }
        }

        self.notificationLock.signal()
    }
}

@objc public func peripheralManagerIsReady(toUpdateSubscribers peripheral: CBPeripheralManager) {
    processNotificationBuffer()
}

Answer 1

问题出在客户端。我的自定义 android 客户端按预期工作。

iOS CoreBluetooth 虚拟外设多重通知

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