In server side, it start a Thread to run a ServerSocket and wait for connection. Once connected, start another Thread to send file.
In client side, start a Thread to connect to server and download file.
In this example, the file to send and receive are fixed test.txt in external storage.
Server Side:
MainActivity.java
package com.example.androidsocketfiletransferserver;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
TextView infoIp, infoPort;
static final int SocketServerPORT = 8080;
ServerSocket serverSocket;
ServerSocketThread serverSocketThread;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
infoIp = (TextView) findViewById(R.id.infoip);
infoPort = (TextView) findViewById(R.id.infoport);
infoIp.setText(getIpAddress());
serverSocketThread = new ServerSocketThread();
serverSocketThread.start();
}
@Override
protected void onDestroy() {
super.onDestroy();
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private String getIpAddress() {
String ip = "";
try {
Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
.getNetworkInterfaces();
while (enumNetworkInterfaces.hasMoreElements()) {
NetworkInterface networkInterface = enumNetworkInterfaces
.nextElement();
Enumeration<InetAddress> enumInetAddress = networkInterface
.getInetAddresses();
while (enumInetAddress.hasMoreElements()) {
InetAddress inetAddress = enumInetAddress.nextElement();
if (inetAddress.isSiteLocalAddress()) {
ip += "SiteLocalAddress: "
+ inetAddress.getHostAddress() + "\n";
}
}
}
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
ip += "Something Wrong! " + e.toString() + "\n";
}
return ip;
}
public class ServerSocketThread extends Thread {
@Override
public void run() {
Socket socket = null;
try {
serverSocket = new ServerSocket(SocketServerPORT);
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
infoPort.setText("I'm waiting here: "
+ serverSocket.getLocalPort());
}});
while (true) {
socket = serverSocket.accept();
FileTxThread fileTxThread = new FileTxThread(socket);
fileTxThread.start();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
public class FileTxThread extends Thread {
Socket socket;
FileTxThread(Socket socket){
this.socket= socket;
}
@Override
public void run() {
File file = new File(
Environment.getExternalStorageDirectory(),
"test.txt");
byte[] bytes = new byte[(int) file.length()];
BufferedInputStream bis;
try {
bis = new BufferedInputStream(new FileInputStream(file));
bis.read(bytes, 0, bytes.length);
OutputStream os = socket.getOutputStream();
os.write(bytes, 0, bytes.length);
os.flush();
socket.close();
final String sentMsg = "File sent to: " + socket.getInetAddress();
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
sentMsg,
Toast.LENGTH_LONG).show();
}});
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.androidsocketfiletransferserver.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="File Transfer Server"
android:textStyle="bold" />
<TextView
android:id="@+id/infoport"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="italic" />
<TextView
android:id="@+id/infoip"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="italic" />
</LinearLayout>
Add permission of "android.permission.INTERNET" and "android.permission.READ_EXTERNAL_STORAGE" to AndroidManifest.xml.
Download the files.Client Side:
MainActivity.java
package com.example.androidsocketfiletransferclient;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.os.Bundle;
import android.os.Environment;
public class MainActivity extends ActionBarActivity {
EditText editTextAddress;
Button buttonConnect;
TextView textPort;
static final int SocketServerPORT = 8080;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextAddress = (EditText) findViewById(R.id.address);
textPort = (TextView) findViewById(R.id.port);
textPort.setText("port: " + SocketServerPORT);
buttonConnect = (Button) findViewById(R.id.connect);
buttonConnect.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
ClientRxThread clientRxThread =
new ClientRxThread(
editTextAddress.getText().toString(),
SocketServerPORT);
clientRxThread.start();
}});
}
private class ClientRxThread extends Thread {
String dstAddress;
int dstPort;
ClientRxThread(String address, int port) {
dstAddress = address;
dstPort = port;
}
@Override
public void run() {
Socket socket = null;
try {
socket = new Socket(dstAddress, dstPort);
File file = new File(
Environment.getExternalStorageDirectory(),
"test.txt");
byte[] bytes = new byte[1024];
InputStream is = socket.getInputStream();
FileOutputStream fos = new FileOutputStream(file);
BufferedOutputStream bos = new BufferedOutputStream(fos);
int bytesRead = is.read(bytes, 0, bytes.length);
bos.write(bytes, 0, bytesRead);
bos.close();
socket.close();
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
"Finished",
Toast.LENGTH_LONG).show();
}});
} catch (IOException e) {
e.printStackTrace();
final String eMsg = "Something wrong: " + e.getMessage();
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
eMsg,
Toast.LENGTH_LONG).show();
}});
} finally {
if(socket != null){
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.androidsocketfiletransferclient.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="File Transfer Client"
android:textStyle="bold" />
<EditText
android:id="@+id/address"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="dstAddress" />
<TextView
android:id="@+id/port"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="@+id/connect"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Connect..." />
</LinearLayout>
Add permission of "android.permission.INTERNET" and "android.permission.WRITE_EXTERNAL_STORAGE" to AndroidManifest.xml.
Download the files.Next:
- Transfer image between Android devices, via Socket
More example of Android Network programming
- Bi-directional communication between Client and Server, using ServerSocket, Socket, DataInputStream and DataOutputStream
