Android bluetooth low energy (ble) writeCharacteristic delay callback

Question

I am implementing a application on Android using BLE Api (SDK 18), and I have a issue that the transfer data process is delay very slow. This is my log.

03-1

Answer 1

This seems to be a problem for me as well. If you delay the calls in the debugger you can confirm that there is a delay when writing to BLE radios. I will be implementing a queue in my application to handle the latency.

Here is what I do for queueing up commands:

public void sendWriteCommandToConnectedMachine(byte[] commandByte) {
    if(commandByte.length > 20)
        dissectAndSendCommandBytes(commandByte);
    else
        queueCommand(commandByte); //TODO - need to figure out if service is valid or not
}

private void queueCommand(byte[] command) {
    mCommandQueue.add(command);

    if(!mWaitingCommandResponse)
        dequeCommand();
}

Hereis what I do for dequeuing BLE commands

private void dequeCommand() {
    if(mCommandQueue.size() > 0) {
        byte[] command = mCommandQueue.get(0);
        mCommandQueue.remove(0);
        sendWriteCommand(command);
    }
}

here is my characteristic write method

@Override
    public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        if(status != BluetoothGatt.GATT_SUCCESS)
            logMachineResponse(characteristic, status);     

        mWaitingCommandResponse = false;
        dequeCommand();
    }