Sending DatagramPacket without internet connection - Android

Question

I use the following code to send a DatagramPacket to a given address:

 InetAddress address = InetAddress.getByName(anIPAddress); DatagramSocket socket = new DatagramSocket(); DatagramPacket packet = new DatagramPacket(packetBytes, packetBytes.length, address, port); socket.send(packet); socket.close(); 

It works fine, but how does this code throw no Exception when there is no internet connection available?

I will disable both Wi-Fi and mobile data, and this code still executes without any errors.

Is there any way to make sure the package is really shipped?

(I don’t care if it reached the goal or not, I just wanted to make sure it was sent)

Answer 1

You can use NetworkInterface.getNetworkInterfaces(); to check which interfaces are available. Then you can check with ni.isUp() .

 Enumeration<NetworkInterface> nets=NetworkInterface.getNetworkInterfaces(); for(int i=0; nets.hasMoreElements(); ++i) { NetworkInterface ni=nets.nextElement(); if (ni.isUp() && !ni.getName().equals("lo")) { //ni is not local break; } } 

Answer 2

Connect the socket to the dataset. Then after several submissions you can get an exception. If the datagram socket is not connected, a routing error occurs that I cannot remember in advance: I will edit it when you have the opportunity to see it.

And yes, I know that UDP is a connectionless protocol. But you can still connect a UDP socket.