android_overview.pdf

Android Overview

Dongsu Han

Outline

• Java network programming overview

• Android Overview

• Android Emulator Overview

• Project Overview

• Getting Started

Java Network Programming

• Java.net.* programming model

– Blocking model, you wait until work is done, maybe

forever

– One thread required per connection

– Socket exposes input and output stream

• Java.nio.* programming model

– Introduced in Java 1.4, non-blocking IO

– New Interface: SocketChannel (in java.nio.channels)

– Reading/writing via Buffer objects rather than

input/output streams

– Select() implemented

Java.net.* Socket API

• Part of the java.net package

– import java.net.*;

• Provides two classes of sockets for TCP

– Socket : client side of socket

– ServerSocket : server side of socket

• Provides one socket type for UDP

– DatagramSocket

Java.net.Socket

• Making a connection

Socket s = new Socket(“hostname”, port);

• The constructor not only creates a socket, but

makes a TCP connection.

• Socket exposes input and output stream.

s.getOutputStream()

s.getInputStream()

• Most of the time you'll chain the input/output

stream to some other input/output stream or

reader object to more easily handle the data.