how to create Socket connection in Android?

how to create Socket connection in Android? - android

I have an application in which I need to create a socket connection. My requirement is: once my socket connection is established it needs to be alive until I personally close it. And every 3 minutes I have to send data packets to the other end. Can anyone provide me some code samples that will help me to do this?

Socket connections in Android are the same as in Java: http://www.oracle.com/technetwork/java/socket-140484.html
Things you need to be aware of:
If phone goes to sleep your app will no longer execute, so socket will eventually timeout. You can prevent this with wake lock. This will eat devices battery tremendously - I know I wouldn't use that app.
If you do this constantly, even when your app is not active, then you need to use Service.
Activities and Services can be killed off by OS at any time, especially if they are part of an inactive app.
Take a look at AlarmManager, if you need scheduled execution of your code.
Do you need to run your code and receive data even if user does not use the app any more (i.e. app is inactive)?

Here, in this post you will find the detailed code for establishing socket between devices or between two application in the same mobile.
You have to create two application to test below code.
In both application's manifest file, add below permission
<uses-permission android:name="android.permission.INTERNET" />
1st App code: Client Socket
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TableRow
android:id="#+id/tr_send_message"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="11dp">
<EditText
android:id="#+id/edt_send_message"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_marginRight="10dp"
android:layout_marginLeft="10dp"
android:hint="Enter message"
android:inputType="text" />
<Button
android:id="#+id/btn_send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:text="Send" />
</TableRow>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="#+id/tr_send_message"
android:layout_marginTop="25dp"
android:id="#+id/scrollView2">
<TextView
android:id="#+id/tv_reply_from_server"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
</RelativeLayout>
MainActivity.java
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
/**
* Created by Girish Bhalerao on 5/4/2017.
*/
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private TextView mTextViewReplyFromServer;
private EditText mEditTextSendMessage;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button buttonSend = (Button) findViewById(R.id.btn_send);
mEditTextSendMessage = (EditText) findViewById(R.id.edt_send_message);
mTextViewReplyFromServer = (TextView) findViewById(R.id.tv_reply_from_server);
buttonSend.setOnClickListener(this);
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_send:
sendMessage(mEditTextSendMessage.getText().toString());
break;
}
}
private void sendMessage(final String msg) {
final Handler handler = new Handler();
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
//Replace below IP with the IP of that device in which server socket open.
//If you change port then change the port number in the server side code also.
Socket s = new Socket("xxx.xxx.xxx.xxx", 9002);
OutputStream out = s.getOutputStream();
PrintWriter output = new PrintWriter(out);
output.println(msg);
output.flush();
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
final String st = input.readLine();
handler.post(new Runnable() {
#Override
public void run() {
String s = mTextViewReplyFromServer.getText().toString();
if (st.trim().length() != 0)
mTextViewReplyFromServer.setText(s + "\nFrom Server : " + st);
}
});
output.close();
out.close();
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
thread.start();
}
}
2nd App Code - Server Socket
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/btn_stop_receiving"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="STOP Receiving data"
android:layout_alignParentTop="true"
android:enabled="false"
android:layout_centerHorizontal="true"
android:layout_marginTop="89dp" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/btn_stop_receiving"
android:layout_marginTop="35dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true">
<TextView
android:id="#+id/tv_data_from_client"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
<Button
android:id="#+id/btn_start_receiving"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="START Receiving data"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="14dp" />
</RelativeLayout>
MainActivity.java
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
/**
* Created by Girish Bhalerao on 5/4/2017.
*/
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
final Handler handler = new Handler();
private Button buttonStartReceiving;
private Button buttonStopReceiving;
private TextView textViewDataFromClient;
private boolean end = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
buttonStartReceiving = (Button) findViewById(R.id.btn_start_receiving);
buttonStopReceiving = (Button) findViewById(R.id.btn_stop_receiving);
textViewDataFromClient = (TextView) findViewById(R.id.tv_data_from_client);
buttonStartReceiving.setOnClickListener(this);
buttonStopReceiving.setOnClickListener(this);
}
private void startServerSocket() {
Thread thread = new Thread(new Runnable() {
private String stringData = null;
#Override
public void run() {
try {
ServerSocket ss = new ServerSocket(9002);
while (!end) {
//Server is waiting for client here, if needed
Socket s = ss.accept();
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
PrintWriter output = new PrintWriter(s.getOutputStream());
stringData = input.readLine();
output.println("FROM SERVER - " + stringData.toUpperCase());
output.flush();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
updateUI(stringData);
if (stringData.equalsIgnoreCase("STOP")) {
end = true;
output.close();
s.close();
break;
}
output.close();
s.close();
}
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
thread.start();
}
private void updateUI(final String stringData) {
handler.post(new Runnable() {
#Override
public void run() {
String s = textViewDataFromClient.getText().toString();
if (stringData.trim().length() != 0)
textViewDataFromClient.setText(s + "\n" + "From Client : " + stringData);
}
});
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_start_receiving:
startServerSocket();
buttonStartReceiving.setEnabled(false);
buttonStopReceiving.setEnabled(true);
break;
case R.id.btn_stop_receiving:
//stopping server socket logic you can add yourself
buttonStartReceiving.setEnabled(true);
buttonStopReceiving.setEnabled(false);
break;
}
}
}

Simple socket server app example
I've already posted a client example at: https://stackoverflow.com/a/35971718/895245 , so here goes a server example.
This example app runs a server that returns a ROT-1 cypher of the input.
You would then need to add an Exit button + some sleep delays, but this should get you started.
To play with it:
install the app
get your phone and PC on a LAN
find your phone's IP with https://android.stackexchange.com/a/130468/126934
run netcat $PHONE_IP 12345
type some lines
Android sockets are the same as Java's, except we have to deal with some permission issues.
src/com/cirosantilli/android_cheat/socket/Main.java
package com.cirosantilli.android_cheat.socket;
import android.app.Activity;
import android.app.IntentService;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Main extends Activity {
static final String TAG = "AndroidCheatSocket";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(Main.TAG, "onCreate");
Main.this.startService(new Intent(Main.this, MyService.class));
}
public static class MyService extends IntentService {
public MyService() {
super("MyService");
}
#Override
protected void onHandleIntent(Intent intent) {
Log.d(Main.TAG, "onHandleIntent");
final int port = 12345;
ServerSocket listener = null;
try {
listener = new ServerSocket(port);
Log.d(Main.TAG, String.format("listening on port = %d", port));
while (true) {
Log.d(Main.TAG, "waiting for client");
Socket socket = listener.accept();
Log.d(Main.TAG, String.format("client connected from: %s", socket.getRemoteSocketAddress().toString()));
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintStream out = new PrintStream(socket.getOutputStream());
for (String inputLine; (inputLine = in.readLine()) != null;) {
Log.d(Main.TAG, "received");
Log.d(Main.TAG, inputLine);
StringBuilder outputStringBuilder = new StringBuilder("");
char inputLineChars[] = inputLine.toCharArray();
for (char c : inputLineChars)
outputStringBuilder.append(Character.toChars(c + 1));
out.println(outputStringBuilder);
}
}
} catch(IOException e) {
Log.d(Main.TAG, e.toString());
}
}
}
}
We need a Service or other background method or else: How do I fix android.os.NetworkOnMainThreadException?
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.cirosantilli.android_cheat.socket"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="22" />
<uses-permission android:name="android.permission.INTERNET" />
<application android:label="AndroidCheatsocket">
<activity android:name="Main">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".Main$MyService" />
</application>
</manifest>
We must add: <uses-permission android:name="android.permission.INTERNET" /> or else: Java socket IOException - permission denied
On GitHub with a build.xml: https://github.com/cirosantilli/android-cheat/tree/92de020d0b708549a444ebd9f881de7b240b3fbc/socket

Related

Python(Server) Android(Client) Socket Programming

I'd like to make a program which connects Python code with Android Studio.
But there has been a problem on android studio which is not showing any UI that I'd like to show on Emulator Screen. I think it is due to "StrictMode". But If I except the StrictMode Code. The Program is stopped. What should I do? Here is the codes.
Python Code(Server)
import socket
import random as r
HOST = "localhost"
PORT = 9999
x = ['10', '20', '30', '40', '50']
y = ['-10', '-20', '-30','-40', '-50']
rssi = ['1.5', '2.5', '3.5', '4.5', '5.5']
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print('Socket created')
try:
s.bind((HOST, PORT))
except socket.error as err:
print('Bind failed. Error Code : ' .format(err))
s.listen(10)
print("Socket Listening")
conn, addr = s.accept()
while(True):
i = r.randint(0, 4)
conn.send(bytes("x : " + x[i] + " y : "+ y[i] + " rssi : " +
rssi[i] + "\r\n", 'UTF-8'))
print("Message sent in python")
data = conn.recv(1024)
print(data.decode(encoding='UTF-8'))
Android Studio(Client) - AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.yangseungchan.socketwithpython">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />
</manifest>
3.Android Studio(Client) - MainActivity.java
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.StrictMode;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
public class MainActivity extends AppCompatActivity {
Button button;
TextView textView;
private Socket clientSocket;
private BufferedReader socketIn;
private PrintWriter socketOut;
private int port = 9999;
private final String ip = "222.99.99.14";
private MyHandler myHandler;
private MyThread myThread;
static String text;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
try{
clientSocket = new Socket(ip, port);
socketIn = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
socketOut = new PrintWriter(clientSocket.getOutputStream(), true);
}catch(Exception e){
e.printStackTrace();
}
myHandler = new MyHandler();
myThread = new MyThread();
myThread.start();
button = (Button)findViewById(R.id.button);
textView = (TextView)findViewById(R.id.textView);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
/*socketPython.Datastack.printStack();
textView.setText((String)SocketwithPython.Datastack.Peek(0));*/
socketOut.println(123);
}
});
}
class MyThread extends Thread{
#Override
public void run() {
while(true){
try{
System.out.println("Trying to read...");
String data = socketIn.readLine();
Message msg = myHandler.obtainMessage();
msg.obj = data;
myHandler.sendMessage(msg);
System.out.println(data);
socketOut.print("Try"+"\r\n");
socketOut.flush();
System.out.println("Message sent");
}
catch(Exception e){
e.printStackTrace();
}
}
}
}
class MyHandler extends Handler {
public void handleMessage(Message msg){
textView.setText(msg.obj.toString());
}
}
}

UDP Client on Android

I have made an UDP Server on a Wi-Fi demo board and test it using and android App (UDP Sender).
I created my own UDP client apps on Android, but it doesn't work.
I created and configured well the socket port and the IPaddress but the app doesn't work and I don't know why.
PS : In the manifest I added the uses-permission to access to the Wi-Fi
her is my simple code
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Udp_Client extends Activity {
/** Called when the activity is first created. */
TextView txt5,txt1;
byte[] send_data = new byte[1024];
Button hello;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txt1 = (TextView)findViewById(R.id.textView1);
txt5 = (TextView)findViewById(R.id.textView5);
hello = (Button) findViewById(R.id.button1);
hello.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
try {
client();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
public void client() throws IOException{
String str="Hello";
int port = 50000;
DatagramSocket client_socket = new DatagramSocket(port);
InetAddress IPAddress = InetAddress.getByName("192.168.0.1");
send_data = str.getBytes();
DatagramPacket send_packet = new DatagramPacket(send_data,str.length(), IPAddress, port);
//client_socket.setBroadcast(true);
client_socket.send(send_packet);
client_socket.close();
}
}
[1]: http://i.stack.imgur.com/aXPhf.png

I found the solution for the problem
The problem was in the manifest
Here is my new code and my manifest
The main in wich I call the UDP_Client :
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity implements View.OnClickListener {
private TextView sceen = null;
private Button launch = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sceen = (TextView)findViewById(R.id.textView1);
launch = (Button)findViewById(R.id.udpbutton);
launch.setOnClickListener(this);
launch.setOnClickListener((OnClickListener) this);
}
public void onClick(View v) {
//UDP Client erstellen
UDP_Client Client = new UDP_Client();
Client.Message = "Your message";
Client.NachrichtSenden();
}
}
The code of my UDP_Client
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import android.annotation.SuppressLint;
import android.os.AsyncTask;
import android.os.Build;
public class UDP_Client
{
private InetAddress IPAddress = null;
private String message = "Hello Android!" ;
private AsyncTask<Void, Void, Void> async_cient;
public String Message;
#SuppressLint("NewApi")
public void NachrichtSenden()
{
async_cient = new AsyncTask<Void, Void, Void>()
{
#Override
protected Void doInBackground(Void... params)
{
DatagramSocket ds = null;
try
{
byte[] ipAddr = new byte[]{ (byte) 192, (byte) 168,43, (byte) 157};
InetAddress addr = InetAddress.getByAddress(ipAddr);
ds = new DatagramSocket(5000);
DatagramPacket dp;
dp = new DatagramPacket(Message.getBytes(), Message.getBytes().length, addr, 50000);
ds.setBroadcast(true);
ds.send(dp);
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
if (ds != null)
{
ds.close();
}
}
return null;
}
protected void onPostExecute(Void result)
{
super.onPostExecute(result);
}
};
if (Build.VERSION.SDK_INT >= 11) async_cient.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
else async_cient.execute();
}
}
The manifest :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.udp_server"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
I added the part of code in my manifest
hope that it will help someone in the future ;)

I think you miss this:
public void connect (InetAddress address, int port)
Of the DataGramSocket Object.
Try:
client_socket.connect(IPAddress, port);
client_socket.send(send_packet);

Error: Could not find or load main class com.example.pdfone.MainActivity

I'm new user in android and I try to view a pdf file using itext jar file.
My code is:
package com.example.pdfone;
public class MainActivity {
public static final String RESULT = "Workspace/one.pdf";
public static void main(String[] args) throws DocumentException, IOException {
Document document = new Document();
PdfWriter.getInstance(document, new FileOutputStream(RESULT));
document.open();
document.add(new Paragraph("Hello World!"));
document.close();
}
}
But when I run this program it gives me Error: Could not find or load main class com.example.pdfone.MainActivity error in console
What can I do? Please help me. Thank you in advance

You need to learn Android first.
Your class needs to extend Activity class.
And iText can only create pdf file, viewing is not possible. Reading is possible. Use Adobe Acrobat or any other PDF tools in Android to view it.
Sample Solutions is as below for PDF Read and Write in Android
100% Working Code Screenshots as below,
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:layout_gravity="center"
tools:context=".MainActivity" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:textAlignment="center"
android:text="Android Read/Write File" />
<EditText
android:id="#+id/fname"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="File Name"
android:text="sample_pdf_file" />
<EditText
android:id="#+id/ftext"
android:layout_width="fill_parent"
android:layout_height="100px"
android:hint="File Text"
android:text="Hello World" />
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/btnwrite"
android:text="Write File" />
<EditText
android:id="#+id/fnameread"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="File Name"
android:text="sample_pdf_file" />
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/btnread"
android:text="Read File" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/filecon" />
</LinearLayout>
FileOperations.java
package com.example.readwrite;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.StringWriter;
import android.util.Log;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.text.pdf.parser.PdfReaderContentParser;
import com.itextpdf.text.pdf.parser.SimpleTextExtractionStrategy;
import com.itextpdf.text.pdf.parser.TextExtractionStrategy;
public class FileOperations {
public FileOperations() {
}
public Boolean write(String fname, String fcontent) {
try {
String fpath = "/sdcard/" + fname + ".pdf";
File file = new File(fpath);
// If file does not exists, then create it
if (!file.exists()) {
file.createNewFile();
}
// step 1
Document document = new Document();
// step 2
PdfWriter.getInstance(document,
new FileOutputStream(file.getAbsoluteFile()));
// step 3
document.open();
// step 4
document.add(new Paragraph("Hello World!"));
document.add(new Paragraph("Hello World2!"));
// step 5
document.close();
Log.d("Suceess", "Sucess");
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
} catch (DocumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
}
public String read(String fname) {
BufferedReader br = null;
String response = null;
try {
StringBuffer output = new StringBuffer();
String fpath = "/sdcard/" + fname + ".pdf";
PdfReader reader = new PdfReader(new FileInputStream(fpath));
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
StringWriter strW = new StringWriter();
TextExtractionStrategy strategy;
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
strategy = parser.processContent(i,
new SimpleTextExtractionStrategy());
strW.write(strategy.getResultantText());
}
response = strW.toString();
} catch (IOException e) {
e.printStackTrace();
return null;
}
return response;
}
}
MainActivity.java
package com.example.readwrite;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
EditText fname, fcontent, fnameread;
Button write, read;
TextView filecon;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fname = (EditText) findViewById(R.id.fname);
fcontent = (EditText) findViewById(R.id.ftext);
fnameread = (EditText) findViewById(R.id.fnameread);
write = (Button) findViewById(R.id.btnwrite);
read = (Button) findViewById(R.id.btnread);
filecon = (TextView) findViewById(R.id.filecon);
write.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
String filename = fname.getText().toString();
String filecontent = fcontent.getText().toString();
FileOperations fop = new FileOperations();
fop.write(filename, filecontent);
if (fop.write(filename, filecontent)) {
Toast.makeText(getApplicationContext(),
filename + ".pdf created", Toast.LENGTH_SHORT)
.show();
} else {
Toast.makeText(getApplicationContext(), "I/O error",
Toast.LENGTH_SHORT).show();
}
}
});
read.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
String readfilename = fnameread.getText().toString();
FileOperations fop = new FileOperations();
String text = fop.read(readfilename);
if (text != null) {
filecon.setText(text);
} else {
Toast.makeText(getApplicationContext(), "File not Found",
Toast.LENGTH_SHORT).show();
filecon.setText(null);
}
}
});
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.readwrite"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.readwrite.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Make sure you have the itextpdf-5.5.1.jar in the right location as below,

How to receive serial data using android bluetooth

I am new to android. I am designing an android application that receives serial data from a hardware device through bluetooth. I am working on Htc desire S. I used the sample Bluetooth chat code to receive data. But the data received is incorrect. It misses some values. Can anyone please provide me any other sample code to receive large amount of data through bluetooth and save it in a file.

try this code :
Activity:
package Android.Arduino.Bluetooth;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.TextView;
import android.widget.EditText;
import android.widget.Button;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;
public class MainActivity extends Activity
{
TextView myLabel;
EditText myTextbox;
BluetoothAdapter mBluetoothAdapter;
BluetoothSocket mmSocket;
BluetoothDevice mmDevice;
OutputStream mmOutputStream;
InputStream mmInputStream;
Thread workerThread;
byte[] readBuffer;
int readBufferPosition;
int counter;
volatile boolean stopWorker;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button openButton = (Button)findViewById(R.id.open);
Button sendButton = (Button)findViewById(R.id.send);
Button closeButton = (Button)findViewById(R.id.close);
myLabel = (TextView)findViewById(R.id.label);
myTextbox = (EditText)findViewById(R.id.entry);
//Open Button
openButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
findBT();
openBT();
}
catch (IOException ex) { }
}
});
//Send Button
sendButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
sendData();
}
catch (IOException ex) { }
}
});
//Close button
closeButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
closeBT();
}
catch (IOException ex) { }
}
});
}
void findBT()
{
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null)
{
myLabel.setText("No bluetooth adapter available");
}
if(!mBluetoothAdapter.isEnabled())
{
Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBluetooth, 0);
}
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if(pairedDevices.size() > 0)
{
for(BluetoothDevice device : pairedDevices)
{
if(device.getName().equals("MattsBlueTooth"))
{
mmDevice = device;
break;
}
}
}
myLabel.setText("Bluetooth Device Found");
}
void openBT() throws IOException
{
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); //Standard SerialPortService ID
mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
mmSocket.connect();
mmOutputStream = mmSocket.getOutputStream();
mmInputStream = mmSocket.getInputStream();
beginListenForData();
myLabel.setText("Bluetooth Opened");
}
void beginListenForData()
{
final Handler handler = new Handler();
final byte delimiter = 10; //This is the ASCII code for a newline character
stopWorker = false;
readBufferPosition = 0;
readBuffer = new byte[1024];
workerThread = new Thread(new Runnable()
{
public void run()
{
while(!Thread.currentThread().isInterrupted() && !stopWorker)
{
try
{
int bytesAvailable = mmInputStream.available();
if(bytesAvailable > 0)
{
byte[] packetBytes = new byte[bytesAvailable];
mmInputStream.read(packetBytes);
for(int i=0;i<bytesAvailable;i++)
{
byte b = packetBytes[i];
if(b == delimiter)
{
byte[] encodedBytes = new byte[readBufferPosition];
System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length);
final String data = new String(encodedBytes, "US-ASCII");
readBufferPosition = 0;
handler.post(new Runnable()
{
public void run()
{
myLabel.setText(data);
}
});
}
else
{
readBuffer[readBufferPosition++] = b;
}
}
}
}
catch (IOException ex)
{
stopWorker = true;
}
}
}
});
workerThread.start();
}
void sendData() throws IOException
{
String msg = myTextbox.getText().toString();
msg += "\n";
mmOutputStream.write(msg.getBytes());
myLabel.setText("Data Sent");
}
void closeBT() throws IOException
{
stopWorker = true;
mmOutputStream.close();
mmInputStream.close();
mmSocket.close();
myLabel.setText("Bluetooth Closed");
}
}
AND Here the layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:ignore="TextFields,HardcodedText" >
<TextView
android:id="#+id/label"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Type here:" />
<EditText
android:id="#+id/entry"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="#id/label"
android:background="#android:drawable/editbox_background" />
<Button
android:id="#+id/open"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="#id/entry"
android:layout_marginLeft="10dip"
android:text="Open" />
<Button
android:id="#+id/send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#id/open"
android:layout_toLeftOf="#id/open"
android:text="Send" />
<Button
android:id="#+id/close"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#id/send"
android:layout_toLeftOf="#id/send"
android:text="Close" />
</RelativeLayout>
Here for Manifest:
add to Application
// permission must be enabled complete
<manifest ....>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<application>
</application>
</manifest>

I tried this out for transmitting continuous data (float values converted to string) from my PC (MATLAB) to my phone. But, still my App misreads the delimiter '\n' and still data gets garbled. So, I took the character 'N' as the delimiter rather than '\n' (it could be any character that doesn't occur as part of your data) and I've achieved better transmission speed - I gave just 0.1 seconds delay between transmitting successive samples - with more than 99% data integrity at the receiver i.e. out of 2000 samples (float values) that I transmitted, only 10 were not decoded properly in my application.
My answer in short is: Choose a delimiter other than '\r' or '\n' as these create more problems for real-time data transmission when compared to other characters like the one I've used. If we work more, may be we can increase the transmission rate even more. I hope my answer helps someone!

The issue with the null connection is related to the findBT() function. you must change the device name from "MattsBlueTooth" to your device name as well as confirm the UUID for your service/device. Use something like BLEScanner app to confrim both on Android.

Take a look at incredible Bluetooth Serial class that has onResume() ability that helped me so much.
I hope this helps ;)

You can use android-bluetooth-serial library to send/receive messages.
Add this package as dependency in app build.gradle.
dependencies {
implementation 'com.github.harry1453:android-bluetooth-serial:v1.1'
// RxJava is also required.
implementation 'io.reactivex.rxjava2:rxjava:2.1.12'
implementation 'io.reactivex.rxjava2:rxandroid:2.0.2'
}
In your app, add a class to interact with device.
private void connectDevice(String mac) {
bluetoothManager.openSerialDevice(mac)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onConnected, this::onError);
}
private void onConnected(BluetoothSerialDevice connectedDevice) {
// You are now connected to this device!
// Here you may want to retain an instance to your device:
deviceInterface = connectedDevice.toSimpleDeviceInterface();
// Listen to bluetooth events
deviceInterface.setListeners(this::onMessageReceived, this::onMessageSent, this::onError);
// Let's send a message:
deviceInterface.sendMessage("Hello world!");
}
private void onMessageSent(String message) {
// We sent a message! Handle it here.
Toast.makeText(context, "Sent a message! Message was: " + message, Toast.LENGTH_LONG).show(); // Replace context with your context instance.
}
private void onMessageReceived(String message) {
// We received a message! Handle it here.
Toast.makeText(context, "Received a message! Message was: " + message, Toast.LENGTH_LONG).show(); // Replace context with your context instance.
}
You can see the readme page for more details on using this package.

Example: Android bi-directional network socket using AsyncTask

Most of the network socket examples I found for Android were one directional only. I needed a solution for a bi-directional data stream. I eventually learned of the AsyncTask. This example shows how to get data from a socket and send data back to it. Due to the blocking nature of a socket that is receiving data, that blocking needs to run in a thread other than the UI thread.
For the sake of example, this code connects to a webserver. Pressing the "Start AsyncTask" button will open the socket. Once the socket is open, the web server waits for a request. Pressing the "Send Message" button will send a request to the server. Any response from the server will be displayed in the TextView. In the case of http, a web server will disconnect from the client once all the data has been sent. For other TCP data streams, the connection will stay up until one side disconnects.
Screenshot:
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.exampleasynctask"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.INTERNET" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".MainActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
res\layout\main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button android:id="#+id/btnStart" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Start AsyncTask"></Button>
<Button android:id="#+id/btnSend" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Send Message"></Button>
<TextView android:id="#+id/textStatus" android:textSize="24sp" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Status Goes Here" />
</LinearLayout>
src\com.exampleasynctask\MainActivity.java:
package com.exampleasynctask;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
Button btnStart, btnSend;
TextView textStatus;
NetworkTask networktask;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnStart = (Button)findViewById(R.id.btnStart);
btnSend = (Button)findViewById(R.id.btnSend);
textStatus = (TextView)findViewById(R.id.textStatus);
btnStart.setOnClickListener(btnStartListener);
btnSend.setOnClickListener(btnSendListener);
networktask = new NetworkTask(); //Create initial instance so SendDataToNetwork doesn't throw an error.
}
private OnClickListener btnStartListener = new OnClickListener() {
public void onClick(View v){
btnStart.setVisibility(View.INVISIBLE);
networktask = new NetworkTask(); //New instance of NetworkTask
networktask.execute();
}
};
private OnClickListener btnSendListener = new OnClickListener() {
public void onClick(View v){
textStatus.setText("Sending Message to AsyncTask.");
networktask.SendDataToNetwork("GET / HTTP/1.1\r\n\r\n");
}
};
public class NetworkTask extends AsyncTask<Void, byte[], Boolean> {
Socket nsocket; //Network Socket
InputStream nis; //Network Input Stream
OutputStream nos; //Network Output Stream
#Override
protected void onPreExecute() {
Log.i("AsyncTask", "onPreExecute");
}
#Override
protected Boolean doInBackground(Void... params) { //This runs on a different thread
boolean result = false;
try {
Log.i("AsyncTask", "doInBackground: Creating socket");
SocketAddress sockaddr = new InetSocketAddress("192.168.1.1", 80);
nsocket = new Socket();
nsocket.connect(sockaddr, 5000); //10 second connection timeout
if (nsocket.isConnected()) {
nis = nsocket.getInputStream();
nos = nsocket.getOutputStream();
Log.i("AsyncTask", "doInBackground: Socket created, streams assigned");
Log.i("AsyncTask", "doInBackground: Waiting for inital data...");
byte[] buffer = new byte[4096];
int read = nis.read(buffer, 0, 4096); //This is blocking
while(read != -1){
byte[] tempdata = new byte[read];
System.arraycopy(buffer, 0, tempdata, 0, read);
publishProgress(tempdata);
Log.i("AsyncTask", "doInBackground: Got some data");
read = nis.read(buffer, 0, 4096); //This is blocking
}
}
} catch (IOException e) {
e.printStackTrace();
Log.i("AsyncTask", "doInBackground: IOException");
result = true;
} catch (Exception e) {
e.printStackTrace();
Log.i("AsyncTask", "doInBackground: Exception");
result = true;
} finally {
try {
nis.close();
nos.close();
nsocket.close();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
Log.i("AsyncTask", "doInBackground: Finished");
}
return result;
}
public void SendDataToNetwork(String cmd) { //You run this from the main thread.
try {
if (nsocket.isConnected()) {
Log.i("AsyncTask", "SendDataToNetwork: Writing received message to socket");
nos.write(cmd.getBytes());
} else {
Log.i("AsyncTask", "SendDataToNetwork: Cannot send message. Socket is closed");
}
} catch (Exception e) {
Log.i("AsyncTask", "SendDataToNetwork: Message send failed. Caught an exception");
}
}
#Override
protected void onProgressUpdate(byte[]... values) {
if (values.length > 0) {
Log.i("AsyncTask", "onProgressUpdate: " + values[0].length + " bytes received.");
textStatus.setText(new String(values[0]));
}
}
#Override
protected void onCancelled() {
Log.i("AsyncTask", "Cancelled.");
btnStart.setVisibility(View.VISIBLE);
}
#Override
protected void onPostExecute(Boolean result) {
if (result) {
Log.i("AsyncTask", "onPostExecute: Completed with an Error.");
textStatus.setText("There was a connection error.");
} else {
Log.i("AsyncTask", "onPostExecute: Completed.");
}
btnStart.setVisibility(View.VISIBLE);
}
}
#Override
protected void onDestroy() {
super.onDestroy();
networktask.cancel(true); //In case the task is currently running
}
}

The SendDataToNetwork task runs in the main ui thread, meaning it will crash a Honeycomb or higher app due to NetworkOnMainThreadException Fatal exception. Here's what my SendDataToNetwork looks like to avoid this issue:
public boolean sendDataToNetwork(final byte[] cmd) {
if (_nsocket.isConnected()) {
Log.i(TAG, "SendDataToNetwork: Writing received message to socket");
new Thread(new Runnable() {
public void run() {
try {
_nos.write(cmd);
} catch (Exception e) {
e.printStackTrace();
Log.i(TAG, "SendDataToNetwork: Message send failed. Caught an exception");
}
}
}).start();
return true;
}
Log.i(TAG, "SendDataToNetwork: Cannot send message. Socket is closed");
return false;
}

Your SendDataToNetwork does not run on the same thread as doInBackground(). There is a possibility that SendDataToNetwork would start sending data before socket is ready.
To avoid all this just use SendDataToNetwork to save data and signal to background thread that data is ready to be sent.
Since there is possibility that user can press button multiple times, while the old data is still being sent, you should have synchronized Queue inside NetworkTask. Then:
Background thread sets up the socket connection and then goes to sleep (via wait()).
On button press, SendDataToNetwork adds data to queue and wakes up the background thread (via notify()).
When background thread wakes up, it first checks the finish flag. If set, it closes connections and exits. If not it reads data from Queue, sends it to network and goes back to sleep.
You should have finish() method which sets a finish flag (atomic variable, like boolean) and wakes the background thread. This is a way to gracefully exit the background thread.
Take a look at how thread synchronization is done: http://www.jchq.net/tutorial/07_03Tut.htm

More interactive example
Similar to the OP's, but you can control host, port and message + there is a popup error notification if the connection failed.
Usage 1:
get Android and a Linux desktop on a LAN
find the IP of the desktop with ifconfig
run netcat -l 12345 on a terminal
on Android, fill in the IP of the desktop
click contact server
on the terminal, type the reply, and hit Ctrl + D
it appears on the output: section
Usage 2:
hostname google.com
port 80
Message: "GET / HTTP/1.1\r\nHost: google.com\r\n\r\n"
Note that some HTTP servers won't close after the reply expecting further requests, and the application will hang until they timeout. Such servers expect you to parse the Content-Width header and close yourself.
If the connection fails, an alert message is shown to the user on a dialog.
Code
Add to AndroidManifest.xml:
<uses-permission android:name="android.permission.INTERNET" />
And the main activity is:
import android.app.Activity;
import android.app.AlertDialog;
import android.app.IntentService;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
public class Main extends Activity {
final static String TAG = "AndroidCheatSocket";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final LinearLayout linearLayout = new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.VERTICAL);
TextView textView;
final String defaultHostname = "192.168.0.";
textView = new TextView(this);
textView.setText("hostname / IP:");
linearLayout.addView(textView);
final EditText hostnameEditText = new EditText(this);
hostnameEditText.setText(defaultHostname);
hostnameEditText.setSingleLine(true);
linearLayout.addView(hostnameEditText);
textView = new TextView(this);
textView.setText("port:");
linearLayout.addView(textView);
final EditText portEditText = new EditText(this);
portEditText.setText("12345");
portEditText.setSingleLine(true);
linearLayout.addView(portEditText);
textView = new TextView(this);
textView.setText("data to send:");
linearLayout.addView(textView);
final EditText dataEditText = new EditText(this);
dataEditText.setText(String.format("GET / HTTP/1.1\r\nHost: %s\r\n\r\n", defaultHostname));
linearLayout.addView(dataEditText);
final TextView replyTextView = new TextView(this);
final ScrollView replyTextScrollView = new ScrollView(this);
replyTextScrollView.addView(replyTextView);
final Button button = new Button(this);
button.setText("contact server");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
button.setEnabled(false);
new MyAsyncTask(Main.this, replyTextView, button).execute(
hostnameEditText.getText().toString(),
portEditText.getText().toString(),
dataEditText.getText().toString());
}
});
linearLayout.addView(button);
textView = new TextView(this);
textView.setText("output:");
linearLayout.addView(textView);
linearLayout.addView(replyTextScrollView);
this.setContentView(linearLayout);
}
private class MyAsyncTask extends AsyncTask<String, Void, String> {
Activity activity;
Button button;
TextView textView;
IOException ioException;
MyAsyncTask(Activity activity, TextView textView, Button button) {
super();
this.activity = activity;
this.textView = textView;
this.button = button;
this.ioException = null;
}
#Override
protected String doInBackground(String... params) {
StringBuilder sb = new StringBuilder();
try {
Socket socket = new Socket(
params[0],
Integer.parseInt(params[1]));
OutputStream out = socket.getOutputStream();
out.write(params[2].getBytes());
InputStream in = socket.getInputStream();
byte buf[] = new byte[1024];
int nbytes;
while ((nbytes = in.read(buf)) != -1) {
sb.append(new String(buf, 0, nbytes));
}
socket.close();
} catch(IOException e) {
this.ioException = e;
return "error";
}
return sb.toString();
}
#Override
protected void onPostExecute(String result) {
if (this.ioException != null) {
new AlertDialog.Builder(this.activity)
.setTitle("An error occurrsed")
.setMessage(this.ioException.toString())
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
} else {
this.textView.setText(result);
}
this.button.setEnabled(true);
}
}
}
On GitHub with build boilerplate.
I've also posted an Android server example at: https://stackoverflow.com/a/35745834/895245
Tested on Android 5.1.1, Sony Xperia 3 D6643.

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

how to create Socket connection in Android? - android

Related

Python(Server) Android(Client) Socket Programming

UDP Client on Android

Error: Could not find or load main class com.example.pdfone.MainActivity

How to receive serial data using android bluetooth

Example: Android bi-directional network socket using AsyncTask

Categories

Resources