Android Sockets always timeout

Question

I have this class which connects to a server through sockets, for some reason it is always timing out from here and I can't figure out why, I thought at first it had to do with it being with onCreate(), thats why doit() even exists. any help would be appreciated. here is my code...

public class Ads extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ads);
        doit();
    };
    public void doit(){
        Socket socket = null;
        FileOutputStream fos = null;
        DataInputStream dis = null;
        BufferedOutputStream buf = null;
        DataOutputStream dos = null;

        try {
            socket = new Socket("192.168.1.106", 4447);
            Bundle extras = getIntent().getExtras();

            String value = extras.getString("keyName");

            dos = new DataOutputStream(
                    new BufferedOutputStream(socket.getOutputStream()));
            dis = new DataInputStream(new BufferedInputStream(
                    socket.getInputStream()));
            //dos.writeChars(value);
            int numFiles = dis.readInt();
            File sdCard = Environment.getExternalStorageDirectory();
            File dir = new File (sdCard.getAbsolutePath() +value);
            dir.mkdirs();
            if (dir.isDirectory()) {
                String[] children = dir.list();
                for (int i=0; i<children.length; i++) {
                    new File(dir, children[i]).delete();
                }
            }
            int n = 0;
            int fileLength = 0;
            for (int i=0;i<numFiles;i++){
                File file = new File(dir, String.valueOf(i)+".png");
                Log.d("debug tag","created file "+file);
            }
            for (int i=0;i<numFiles;i++){
                fileLength = dis.readInt();


                byte[] temp = new byte[(int) fileLength];

                String path = sdCard.getAbsolutePath()+value+"/"+i+".png";
                buf = new BufferedOutputStream(new FileOutputStream(path));
                while ((fileLength > 0) && (n = dis.read(temp, 0, (int) Math.min(temp.length, fileLength))) != -1) {
                    buf.write(temp,0,n);
                    buf.flush();
                    fileLength -= n;
                }
                //buf.close();

            Log.d("debug tag","the file is "+temp.length+" bytes long");
            }
            // now read in text files

             n = 0;
             fileLength = 0;
            for (int i=0;i<numFiles;i++){
                File file = new File(dir, String.valueOf(i)+".txt");
                Log.d("debug tag","created file "+file);
            }
            for (int i=0;i<numFiles;i++){
                fileLength = dis.readInt();


                byte[] temp = new byte[(int) fileLength];

                String path = sdCard.getAbsolutePath()+value+"/"+i+".txt";
                buf = new BufferedOutputStream(new FileOutputStream(path));
                while ((fileLength > 0) && (n = dis.read(temp, 0, (int) Math.min(temp.length, fileLength))) != -1) {
                    buf.write(temp,0,n);
                    buf.flush();
                    fileLength -= n;
                }
                //buf.close();

            Log.d("debug tag","the text file is "+temp.length+" bytes long");
            }
            generateListView(sdCard.getAbsoluteFile()+value+"/");
        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 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 (fos != null){
                try {
                    fos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

            if (dis != null){
                try {
                    dis.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (dos != null){
                try {
                    dos.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

;

Answer 1

I'm afraid the question lacks some important details (it timeouts when connecting, right?), but my blind guess is that your device is using cellular connection, while 192.168.1.106 is on your WiFi network - IPs in the 192.168.x.x pool are private IP addresses, and obviously you can't connect to any such IP address over Internet.

But there's another serious problem with your code - you're trying to make blocking I/O calls in onCreate() - which is executed in the main thread of the application. You should never do this (actually, as soon as you try it on Android 3.x or higher, you'll get NetworkOnMainThreadException). Network I/O should always happen in another thread, either explicitly, or perhaps using AsyncTask (which runs the background thread for you).

For a good introduction, see this post and Designing for Responsiveness guide.