I have a foreground service with a thread that monitors UDP packets. It works perfectly until I leave the phone alone for about 5 minutes (but not exactly 5 minutes), then it stops sending the updates it's getting from UDP packets. This is 100% reproducible, and I can see the UDP packets on the network with a packet capture, so I know they are there.
private class ArduinoUDPListener extends Thread {
private MulticastSocket socket;
private AtomicBoolean done;
private Instant lastMsgTime;
public void run() {
PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"MyApp::MyWakelockTag");
wakeLock.acquire();
WifiManager wm = (WifiManager)getSystemService(Context.WIFI_SERVICE);
WifiManager.MulticastLock multicastLock = null;
multicastLock = wm.createMulticastLock("udp for hamwin");
multicastLock.acquire();
WifiManager.WifiLock wifiLock = null;
wifiLock = wm.createWifiLock(WifiManager.WIFI_MODE_FULL_HIGH_PERF, "wifi lock for ham");
wifiLock.acquire();
lastMsgTime = Instant.MIN;
done = new AtomicBoolean(false);
try {
socket = new MulticastSocket(7234);
InetAddress group = InetAddress.getByName("239.1.1.234");
socket.joinGroup(group);
socket.setReuseAddress(true);
socket.setBroadcast(true);
if (!socket.getBroadcast()) {
socket.close();
return;
}
socket.setSoTimeout(100);
byte[] buf = new byte[65535];
DatagramPacket p = new DatagramPacket(buf, 65535);
while (!done.get()) {
try {
socket.receive(p);
} catch (SocketTimeoutException e) {
// retry
continue;
} catch (IOException e) {
e.printStackTrace();
break;
}
// Process packet,
// sometimes we just stop getting here after a few minutes of normal activity if the phone is not touched.
if (mainThreadHdlr != null) {
Message msg = mainThreadHdlr.obtainMessage();
msg.obj = update;
mainThreadHdlr.sendMessage(msg);
Log.i("Net", "Sent update");
} else {
System.out.println("null?");
}
}
}
socket.close();
}
Are there any other wake locks I should be taking? Is there anything else I can do to keep the network/thread alive? I'm not even sure in what way it has stopped. Network? CPU? Other?
UPDATE After adding some more detailed logging I found that the SocketTimeoutException gets thrown at regular intervals, always, but the UDP packets are getting sent to the application less frequently when the screen is off! I'm expecting a packet every second and sometimes they wont arrive for ~5-10 seconds or more when the screen is off.
