BLE：使用CoreBluetooth在2个ios设备之间传输图像-Java 学习之路

所以我有2个iOS设备：一个是Peripheral，另一个是Central . 我希望数据是图像 . 我尝试了一个字符串值，它工作正常，但有图像我得到这个错误：“read_user_chunkIDOT：1221：无效的PNG文件：没有有效的iEnd块”，我也可以看到字节是不同的（可选（526字节）），当我得到它们时它们会更大 .

这是外围设备：

if let img = UIImage(named: "maiden") {
        let data = UIImagePNGRepresentation(img)
        let base64 = data?.base64EncodedData(options: .lineLength64Characters)
        let char = CBMutableCharacteristic(type: CHAR_UUID, properties: [.read], value: base64!, permissions: [.readable])
        let myRoei = CBMutableService(type: RX_UUID, primary: true)

        myRoei.characteristics = [char]
        cameraPeripheralManager.add(myRoei)
        cameraPeripheralManager.startAdvertising([CBAdvertisementDataServiceUUIDsKey:[RX_UUID], CBAdvertisementDataLocalNameKey: advertisementData])
    }

这是Central里面的didUpdateValueFor特性：

print(characteristic.value as Any)
    switch characteristic.uuid {
    case CHAR_UUID:
        let image = UIImage(data: Data(base64Encoded: characteristic.value!, options: .ignoreUnknownCharacters)!)

        self.imageView.image = image
        _ = bodyLocation(from: characteristic)
    case RX_UUID: break
       // onHeartRateReceived(bpm)
    default:
        print("Unhandled Characteristic UUID: \(characteristic.uuid)")
    }

想知道我哪里错了 . 提前致谢！

1 Answer

所以我用这段代码管理了这样做：

func sendData() {
    if sendingEOM {
        // send it
        let didSend = cameraPeripheralManager?.updateValue(
            "EOM".data(using: String.Encoding.utf8)!,
            for: char!,
            onSubscribedCentrals: nil
        )
        // Did it send?
        if (didSend == true) {
            // It did, so mark it as sent
            sendingEOM = false
            print("Sent: EOM")
        }
        return
    }

    // We're not sending an EOM, so we're sending data

    // Is there any left to send?
    guard sendDataIndex! < (dataToSend?.count)! else {
        // No data left.  Do nothing
        return
    }

    // There's data left, so send until the callback fails, or we're done.
    var didSend = true

    while didSend {
        // Make the next chunk

        // Work out how big it should be
        var amountToSend = dataToSend!.count - sendDataIndex!;

        // Can't be longer than 20 bytes
        if (amountToSend > NOTIFY_MTU) {
            amountToSend = NOTIFY_MTU;
        }

        // Copy out the data we want
        let chunk = dataToSend!.withUnsafeBytes{(body: UnsafePointer<UInt8>) in
            return Data(
                bytes: body + sendDataIndex!,
                count: amountToSend
            )
        }

        // Send it
        didSend = cameraPeripheralManager!.updateValue(
            chunk as Data,
            for: char!,
            onSubscribedCentrals: nil
        )

        // If it didn't work, drop out and wait for the callback
        if (!didSend) {
            return
        }

        let stringFromData = NSString(
            data: chunk as Data,
            encoding: String.Encoding.utf8.rawValue
        )

        print("Sent: \(String(describing: stringFromData))")

        // It did send, so update our index
        sendDataIndex! += amountToSend;

        // Was it the last one?
        if (sendDataIndex! >= dataToSend!.count) {

            // It was - send an EOM

            // Set this so if the send fails, we'll send it next time
            sendingEOM = true

            // Send it
            let eomSent = cameraPeripheralManager!.updateValue(
                "EOM".data(using: String.Encoding.utf8)!,
                for: char!,
                onSubscribedCentrals: nil
            )

            if (eomSent) {
                // It sent, we're all done
                sendingEOM = false
                print("Sent: EOM")
            }

            return
        }
    }
}
Very useful code that helps you break the data into chunks and deliver the last chunk with a string to notify the central device that the transfer finished.

BLE：使用CoreBluetooth在2个ios设备之间传输图像

1 Answer

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