Android Introduction
Hello Socket Programming
TCP and UDP
@2011 Mihail L. Sichitiu
1
Goal

Convert the Java Socket Programming
Project to Android
Text input from the user –
sent to the same server(s)
as before
Answer from the server(s)
Sends the input from the
user to the UPD Server
Sends the input from the
user to the TCP Server
@2010 Mihail L. Sichitiu
2
Layout
Create a simple layout that will include the
required elements:
 EditText
 TextView
 Buttons
 Register one “OnClickedListener()” for
each of the buttons
 Test functionality (make a toast for each
listener)

@2010 Mihail L. Sichitiu
3
Socket Programming
Define most variables as members of the
main Activity Class
 Rename:




DatagramSocket clientSocket ->
DatagramSocket udpClientSocket
Socket clientSocket -> Socket tcpSocket;
Adapt the code from pure Java to Android
(especially the input and output strings)
by filling in the two OnClickListeners
@2010 Mihail L. Sichitiu
4
Handling Exceptions

Many network operations throw exceptions (as they can
fail). In the original code they were just thrown out of main
– in Android we have to handle them!

Try{
Operations that may fail and throw an exception;
}catch (Exception e) {
Log.e(TAG,"Caught UDP Exception: “ + e.getMessage());
Toast.makeText(HelloNets.this, "UDP Error"+
e.getMessage()), Toast.LENGTH_LONG).show();
}
@2010 Mihail L. Sichitiu
5
Running it
First give the application INTERNET
permissions (like in the WebView)
 Implement the UDP and TCP functionality
separately
 Run and debug.

@2010 Mihail L. Sichitiu
6