CODEWITHSUNDEEP
androidnetwork-programmingudp
Debadeep Sen
Debadeep Sen

Reputation: 465

UDP transmission stops after sometime

Ok, so here's my problem. I have an android app transmitting UDP packets to a PC (a java program which listens for the packets), based on user interactions with the android device. To keep things simple, let's say this is happening - the user taps the screen of the phone, and it sends a UDP packet with the coordinates of the point where the user tapped. The listener program receives and reads this packet, and outputs the string received, using System.out.println().

Now, what's happening is that the program works perfectly for the first few packets. Then it stops working, as in, the listener program on the desktop does not display any output. Now, the issue is probably with the transmission, as I have a text label on the app (for testing purpose) that displays what is being transmitted, so the transmission packet is definitely being built properly. But I have no idea on how to understand if this is a problem with sending the data (on the android device side), or receiving (on the desktop side). How can I find out what's wrong and solve this issue?

Upvotes: 2

Views: 540

Answers (2)

Trisha
Trisha

Reputation: 11

Are you using native code or Java classes? I have tried both, and with the NDK (i.e. sockets written as C functions being called from Java) I have seen erratic behavior on the server side, mostly due to threading issues. Using the Java Socket class I have not had issues however. Moreover, if your Android app is the client, that should not be the problem. I would also use Wireshark to check whether the packets are reaching the PC.

Upvotes: 1

Binaek Sarkar
Binaek Sarkar

Reputation: 636

I have mostly worked with TCP transmission and all the UDP i have done are mostly Copy-Paste [:-)] or with APIs

For TCP, after transmission, I throw a debug message, which helps me to know that the transmission occurred properly. But in this case, your write will have to be blocking.

Also, you could use a Packet Tracer on your listener terminal to determine whether it is receiving the packets properly. The one I love is WireShark (I think its a fork of Ethereal). Its really easy to use. You tell it which interface to listen on and give a filter and it will list out the packets as and when they come.

However, if you are using Windows 7, you will need admin privileges.

Upvotes: 1

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