Develop Reference

Android Software caused connection abort and Async task

I use a bluetooth_access Async task to establish a connection and I need continue to use the input stream and out stream of the bluetooth socket I established.
The issue I having is when I clicked button1 or button2, it sometimes (not all the times) cause Software caused connection abort. It got tripped on out.write(bytes) when clicked.
public class MainActivity extends Activity implements OnClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = (Button)this.findViewById(R.id.button1);
button2 = (Button)this.findViewById(R.id.button2);
button3 = (Button)this.findViewById(R.id.button3);
button1.setEnabled(false);
button2.setEnabled(false);
button3.setEnabled(false);
button1.setOnClickListener(this);
button2.setOnClickListener(this);
button3.setOnClickListener(this);
try {
for (int i = 0; i < 3; i++) {
test();
}
} catch (Exception e) {
e.printStackTrace();
}
}
private boolean connected = false;
private BluetoothSocket sock;
private InputStream in;
private OutputStream out;
private Button button1;
private Button button2;
private Button button3;
private TextView data_t;
private BufferedReader in_read;
public void test() throws Exception {
if (connected) {
return;
}
new bluetooth_access().execute("");
}
#Override
public void onClick(View v){
// TODO Auto-generated method stub
if(v.equals(button1)){
String s = "turn left";
byte[] bytes=s.getBytes();
try {
out.write(bytes);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(v.equals(button2)){
String s = "turn right";
byte[] bytes=s.getBytes();
try {
out.write(bytes);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//new post_data().execute("");
}
if(v.equals(button3)){
String s = "read ADC";
byte[] bytes=s.getBytes();
try {
out.write(bytes);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class bluetooth_access extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
BluetoothDevice Pi = BluetoothAdapter.getDefaultAdapter().
getRemoteDevice("00:15:83:0C:BF:EB");
Method m=null;
try {
m = Pi.getClass().getMethod("createRfcommSocket",
new Class[] { int.class });
} catch (NoSuchMethodException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
sock = (BluetoothSocket)m.invoke(Pi, Integer.valueOf(1));
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
sock.connect();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.d("PiTest", "++++ Connected");
return null;
}
#Override
protected void onPostExecute(String result) {
;
TextView text = (TextView) findViewById(R.id.textView5);
text.setText("Connected through Bluetooth");
button1.setEnabled(true);
button2.setEnabled(true);
button3.setEnabled(true);
// original
try {
in = sock.getInputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
out=sock.getOutputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
}
}

You are trying to write to a socket stream from your main UI thread (from onClick), i would consider doing all socket communication from asynctask itself, or another thread if needed.
your connected variable is not being set, not sure if that was intentional, it can cause multiple execution of your bluetooth asynctask.

Android Socket communication Exception

My server code
public class RemoteServer {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket socket = null;
DataInputStream dataInputStream = null;
DataOutputStream dataOutputStream = null;
try {
serverSocket = new ServerSocket(8888);
System.out.println("Listening :8888");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
while (true) {
try {
socket = serverSocket.accept();
dataInputStream = new DataInputStream(socket.getInputStream());
dataOutputStream = new DataOutputStream(
socket.getOutputStream());
System.out.println("ip: " + socket.getInetAddress());
System.out.println("message: " + dataInputStream.readUTF().toUpperCase());
dataOutputStream.writeUTF("sajol");
} 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();
}
}
if (dataInputStream != null) {
try {
dataInputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (dataOutputStream != null) {
try {
dataOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}
My client code for android device
public class Client extends Activity {
EditText textOut;
TextView textIn;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Button b = findViewById(R.id.b)
textOut = (EditText) findViewById(R.id.t);
Button buttonSend = (Button) findViewById(R.id.b);
textIn = (TextView) findViewById(R.id.te);
buttonSend.setOnClickListener(buttonSendOnClickListener);
}
Button.OnClickListener buttonSendOnClickListener = new Button.OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Thread t = new Thread(r);
t.start();
}
};
Runnable r = new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
Socket socket = null;
DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream = null;
try {
socket = new Socket("192.168.1.239", 8888);
dataOutputStream = new DataOutputStream(
socket.getOutputStream());
dataInputStream = new DataInputStream(socket.getInputStream());
dataOutputStream.writeUTF(textOut.getText().toString());
textIn.setText(dataInputStream.readUTF());
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
Log.e("Sajol", e+"");
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("Sajol", e+"");
e.printStackTrace();
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("Sajol", e+"");
}
}
if (dataOutputStream != null) {
try {
dataOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("Sajol", e+"");
}
}
if (dataInputStream != null) {
try {
dataInputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("Sajol", e+"");
}
}
}
}
};
}
when i run this client code on emulator server response .But when i run client code on real device server program does not response.I found the ip address using in my code by execute ipconfig command on cmd. My pc(windows 7) and android device both are connected to wifi.
i got following exception
java.net.SocketTimeoutException: Connection timed out
Please give me solution

display all textfiles in listview created by your app

The code creates a text file in local memory, but how do I get all files created by my application in a list view:
public class newfile extends Activity {
public EditText textBox,textbox2;
FileOutputStream fos=null;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.newfile);
Button save = (Button) findViewById(R.id.btnSave);
save.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
textBox = (EditText) findViewById(R.id.txtText1);
textbox2 = (EditText) findViewById(R.id.fname);
String FILENAME = textbox2.getText().toString();
String value = textBox.getText().toString();
try{
fos = openFileOutput(FILENAME,MODE_WORLD_WRITEABLE);
}
catch(IOException e)
{
e.printStackTrace();
}
byte[] buffer = value.getBytes();
try {
fos.write(buffer);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fos.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fos.close();
Toast.makeText(getBaseContext(), "File saved successfully!", Toast.LENGTH_LONG).show();
finish();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}

You can get a list all application files using Context.fileList. Then use ArrayAdapter to populate your list view

Adding events to google calendar from my app

I have the code. No errors in eclipse. But in the emulator, I'm getting "Application has stopped unexpectedly" error. I have done a lot of research but I'm not able to get rid of this. All I want the app to do is to add events to my google calendar.
The code snippet:
public class HelloAndroid extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set up the URL and the object that will handle the connection:
URL postUrl = null;
try {
postUrl = new URL("http://www.google.com/calendar/feeds/xyz#gmail.com/private/full");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
CalendarService myService = new CalendarService("exampleCo-exampleApp-1");
try {
myService.setUserCredentials("xyz","xyz123");
} catch (AuthenticationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
EventEntry myEntry = new EventEntry();
myEntry.setTitle(new PlainTextConstruct("test event"));
myEntry.setContent(new PlainTextConstruct("Working!!"));
Person author = new Person("It's me", null, "me#home.com");
myEntry.getAuthors().add(author);
DateTime startTime = DateTime.parseDateTime("2011-07-20T15:00:00-08:00");
DateTime endTime = DateTime.parseDateTime("2011-07-20T17:00:00-08:00");
When eventTimes = new When();
eventTimes.setStartTime(startTime);
eventTimes.setEndTime(endTime);
myEntry.addTime(eventTimes);
try {
EventEntry insertedEntry = myService.insert (postUrl, myEntry);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ServiceException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
setContentView(R.layout.main);
}
Is it anything to do with the code or the manifest?

Android Client, Pc Server Socket d'ont work over 3g

I try to create a client server socket beetwen my droid(client) and my PC(server), when i am in local(over wifi) it work perfectely, but when il try over 3G i get this exception when the server try to get clientsocket.getOutputStream()
at java.lang.Thread.run(Unknown Source)
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.io.DataInputStream.readUnsignedShort(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
What's the probleme, do eny one know the solution of this?
help please :-(
The Server
public class Server {
ServerSocket serverSocket;
public LinkedBlockingQueue<CDRecCourseDisplay> recCours;
public LinkedList<ClientMail> clientMails;
static Server server;
public static Server getInstance(){
if(server == null){
server = new Server();
}
return server;
}
Server() {
// TODO Auto-generated constructor stub
try {
serverSocket = new ServerSocket(54444);
recCours = new LinkedBlockingQueue<CDRecCourseDisplay>(10);
clientMails = new LinkedList<ClientMail>();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.start();
}
private void start(){
new Thread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
while (true){
try {
Socket socket = serverSocket.accept();
new Thread(new Client(socket)).start();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
class Client implements Runnable{
Socket socket;
DataInputStream in;
DataOutputStream out;
public Client(Socket socket) {
// TODO Auto-generated constructor stub
this.socket = socket;
if(socket == null) return;
try {
InputStream i = socket.getInputStream();
OutputStream o = socket.getOutputStream();
in = new DataInputStream(i);
out = new DataOutputStream(o);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void run() {
// TODO Auto-generated method stub
new Thread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
while(true){
try {
out.writeUTF("Test Message");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
new Thread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
while(true){
try {
String buf = in.readUTF();
Log.d("MESSAGE", buf);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
}
}
and the client
class Client implements Runnable{
Socket socket;
DataInputStream in;
DataOutputStream out;
public void run() {
// TODO Auto-generated method stub
boolean conected = false;
while(!conected){
try {
Thread.sleep(500);
socket = new Socket("213.233.216.25", 54444);
in = new DataInputStream(socket.getInputStream());
out = new DataOutputStream(socket.getOutputStream());
conected = true;
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
Log.e("ERROR :", e.getMessage());
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("ERROR :", e.getMessage());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
Log.e("ERROR :", e.getMessage());
}
}
new Thread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
while(true){
try {
String buf = in.readUTF();
log.d("MESSAGE", buf);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
new Thread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
while(true){
try {
out.writeUTF("Test message from the phone");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
}

Most networks (Wifi and 3G) use NAT. NAT allows outbound connections, but prevents inbound (internet to device) connections.
When your server and device are both on the same network, as in your case, then this works as you are not traversing NAT gateway.
Rationale: what you are trying to do (connecting from internet to device) will not work in most networks.