I am working on an Android app that will receive multicast packets from a network that already outputs reliable multicast data on 239.255.x.x . I have verified that my device can receive multicast with another application. I'm new to Java and Android but I did confirm that my original code to gather the Multicast info worked in a java application and have been struggling to get everything working in the Android side of things. I have permissions set in the manifest,
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
the networking portion of code runs in an Asynctask as to not crash the app but my Multicast.receive() calls all result in a time out.Is there something else I am missing or something that prevents multicast sockets from working in the asynctask class?
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Button button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
new getACN.execute();
}
});
}
public class getACN extends AsyncTask<Void, Void, String> {
@Override
public String doInBackground(Void... Void) {
byte[] buf = new byte[1000];
try {
WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
MulticastLock multicastLock = wifiManager.createMulticastLock("sACN");
multicastLock.acquire();
InetAddress group = InetAddress.getByName("239.255.0.3");
DatagramPacket recv = new DatagramPacket(buf,buf.length);
MulticastSocket sock = new MulticastSocket(5568);
sock.joinGroup(group);
sock.setSoTimeout(1000);
sock.receive(recv);
sock.leaveGroup(group);
} catch (IOException e) {
return e.getMessage();
} catch (SecurityException e) {
return e.getMessage();
}
return Arrays.toString(buf);
}
@Override
protected void onPostExecute(String result){
TextView textView = (TextView) findViewById(R.id.text01);
textView.setText(result);
}
}
}
