Question

I’m getting “NetworkOnMainThreadException”

I’m sending UDP packets from a AsyncTask but from a Sensor event, my guess is that the Sensor event triggers on the main UI thread.

I want to send UdpPackets when new values are available from the sensor, what is the best way since I cant do it from the sensor event?

Answer 1

Spawning a thread for each sensor event isn’t very good, and have a separate thread that polls new data also has problems (WarrenFaith answer).

I ended up using a CyclicBarrier, like this, a infinite loop inside a seperate thread

running = true;
worker = new Thread(new Runnable() {
    public void run(){

         while(running) {
             try {
                 sync.await();
                 Send();
             } catch(Exception e) {}
         }
         socket.disconnect();
    }
}); 
worker.start();

The thread will halt on the sync.await(); line

Until new data is available from the sensor

SensorEventListener allListener = new SensorEventListener() {
    public void onSensorChanged(SensorEvent event) {
        if(sendOrientation) {
            float R[] = new float[9];
            float I[] = new float[9];
            boolean success = sensorManager.getRotationMatrix(R, I, acc, mag);
            if (success) {  
                SensorManager.getOrientation(R, orientation);    
            }
        }

        if(sync.getNumberWaiting() > 0)
            sync.reset();   
    }
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {    
    }
};  

And sync.reset(); is called, which will let the poller thread proceed