我已经通过蓝牙LE为发送大型ByteArray创建了BLE发送器类 发送过程的逻辑如下：
我的问题是：有更好的方法吗？ 我发现多次写入特性需要一些延迟至少20毫秒。有什么方法可以避免这种情况吗？
更改了实施而不是20毫秒，我正在等待回调 onCharacteristicWrite Emil建议。并且还改变了准备方法以减少18字节块之间的计算时间发送：
class BluetoothLEDataSender(
val characteristicForSending: BluetoothGattCharacteristic,
val characteristicForNotifyDataSend: BluetoothGattCharacteristic,
private val config: BluetoothLESenderConfiguration = BluetoothLESenderConfiguration(),
val bluetoothLeService: WeakReference<BluetoothLeService>) : HandlerThread("BluetoothLEDataSender") {
data class BluetoothLESenderConfiguration(val sendingIntervalMillis: Long = 20L, val chunkSize: Int = 1000, val retryForFailureInSeconds: Long = 3)
private val toaster by lazy { Toast.makeText(bluetoothLeService.get()!!,"",Toast.LENGTH_SHORT) }
companion object {
val ACTION_DATA_SEND_FINISHED = "somatix.com.bleplays.ACTION_DATA_SEND_FINISHED"
val ACTION_DATA_SEND_FAILED = "somatix.com.bleplays.ACTION_DATA_SEND_FAILED"
}
lateinit var dataToSend: List<BlocksQueue>
val messageHandler by lazy { SenderHandler()}
var currentIndex = 0
public fun notifyDataState(receivedChecksum: String) {
val msg = Message()
msg.arg1 = receivedChecksum.toInt()
messageHandler.sendMessage(msg)
}
inner class BlocksQueue(val initialCapacity:Int):ArrayBlockingQueue<ByteArray>(initialCapacity)
inner class BlockSendingTask:Runnable{
override fun run() {
executeOnUiThread({ toaster.setText("Executing block: $currentIndex")
toaster.show()})
sendNext()
}
}
public fun sendMessage(messageByteArray: ByteArray) {
start()
dataToSend = prepareSending(messageByteArray)
bluetoothLeService.get()?.setEnableNotification(characteristicForSending,true)
val descriptor = characteristicForSending.getDescriptor(DESCRIPTOR_CONFIG_UUID)
descriptor.value = BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE
bluetoothLeService.get()?.writeDescriptor(descriptor)
characteristicForNotifyDataSend.value = "${messageByteArray.size}:${config.chunkSize}:${dataToSend.size}".toByteArray()
toaster.setText(String(characteristicForNotifyDataSend.value))
toaster.show()
messageHandler.postDelayed({bluetoothLeService.get()?.writeCharacteristic(characteristicForNotifyDataSend)}, config.sendingIntervalMillis)
}
private fun prepareSending(messageByteArray: ByteArray): ArrayList<BlocksQueue> {
with(config)
{
var chunksNumber = messageByteArray.size / config.chunkSize
chunksNumber = if (messageByteArray.size == chunksNumber * config.chunkSize) chunksNumber else chunksNumber + 1
val chunksArray = ArrayList<BlocksQueue>()
(0 until chunksNumber).mapTo(chunksArray) {
val start = it * chunkSize
val end = if ((start + chunkSize) > messageByteArray.size) messageByteArray.size else start + chunkSize
val sliceArray = messageByteArray.sliceArray(start until end)
listOfCheckSums.add(sliceArray.checkSum())
var capacity = sliceArray.size / 18
capacity = if(sliceArray.size - capacity*18 == 0) capacity else capacity + 1
//Add place for checksum
val queue = BlocksQueue(capacity+1)
for(i in 0 until capacity){
val start1 = i *18
val end1 = if((start1 + 18)<sliceArray.size) start1 +18 else sliceArray.size
queue.add(sliceArray.sliceArray(start1 until end1))
}
queue.add(sliceArray.checkSum().toByteArray())
queue
}
return chunksArray
}
}
fun sendNext(){
val currentChunk = dataToSend.get(currentIndex)
val peek = currentChunk.poll()
if(peek != null)
{
if(currentChunk.initialCapacity > currentBlock+1)
{
val indexByteArray = if(currentBlock>9) "$currentBlock".toByteArray() else "0${currentBlock}".toByteArray()
characteristicForSending.value = indexByteArray + peek
}
else{
characteristicForSending.value = peek
}
bluetoothLeService.get()?.writeCharacteristic(characteristicForSending)
currentBlock++
}
else
{
Log.i(TAG, "Finished chunk $currentIndex")
currentBlock = 0
}
}
private val TAG= "BluetoothLeService"
@SuppressLint("HandlerLeak")
inner class SenderHandler:Handler(looper){
private var failureCheck:FailureCheck? = null
override fun handleMessage(msg: Message) {
super.handleMessage(msg)
currentIndex = msg.arg1
if(currentIndex < dataToSend.size)
{
if (currentIndex!= 0 && failureCheck != null)
{
removeCallbacks(failureCheck)
}
failureCheck = FailureCheck(currentIndex)
post(BlockSendingTask())
postDelayed(failureCheck,TimeUnit.MILLISECONDS.convert(config.retryForFailureInSeconds,TimeUnit.SECONDS))
}
else {
if (currentIndex!= 0 && failureCheck != null)
{
removeCallbacks(failureCheck)
}
val intent= Intent(ACTION_DATA_SEND_FINISHED)
bluetoothLeService.get()?.sendBroadcast(intent)
}
}
private inner class FailureCheck(val index:Int):Runnable{
override fun run() {
if (index==currentIndex){
val intent= Intent(ACTION_DATA_SEND_FAILED)
bluetoothLeService.get()?.sendBroadcast(intent)
}
}
}
}
}
答案 0 :(得分：2)
等待20毫秒的事情是什么？使用特征写入泵送数据的首选方法是首先使用“无响应写入”（https://developer.android.com/reference/android/bluetooth/BluetoothGattCharacteristic.html#WRITE_TYPE_NO_RESPONSE），然后执行写入，然后等待onCharacteristicWrite回调，然后立即执行下一次写入。您需要等待onCharacteristicWrite回调，因为API不允许您一次有多个待处理命令/请求。
答案 1 :(得分：0)