I think you're doing it the hard way, but maybe that's on purpose. The easy way is to use UrlConnection instead of sockets and use AsyncTask instead of creating threads by hand. AsyncTask uses a thread pool and makes it really easy to hook up actions and responses with the UI. Trying to get a response back to the UI from a non-UI thread is a well-known headache for Anfroid programmers.
On Wed, Apr 7, 2010 at 10:36 PM, raqz <[email protected]> wrote: > Hi, > > I have a main class activity that does the task of sending control to > other activities on click of a button. I am also starting a thread in > the main class. This thread basically sets up a connection with the > server and is active throughout the lifetime of the application. > I have two functions in the thread class, send and receive data from > server. Therefore, when the other activities need to send/receive data > from server, they use those particular functions. > First of all please let me know if what I am trying to do is fine as > per the architecture of the operating system. If its fine, when I try > to run the code, the app crashes and i see a NullPointerException and > a RuntimeException in the DDMS log. > Could some one please help me out in this or suggest a better way to > implement the concept. > Also, please be assured that, the other functionality of the code > works perfectly fine. > The main class code is as below > [code] > package com.getfriends; > > import java.util.ArrayList; > import java.util.Iterator; > import java.util.List; > import java.util.StringTokenizer; > import android.app.Activity; > import android.app.ListActivity; > import android.os.Bundle; > import android.widget.ArrayAdapter; > import android.widget.ListView; > import android.widget.Toast; > > public class GetFriendsActivity extends Activity{ > > > private MyFriend obj= new MyFriend(); > List<MyFriend> listOfFriends = new ArrayList<MyFriend>(); > > int i=0; > private String FName=null; > private String LName=null; > private String Latitude=null; > private String Longitude=null; > private String TimeStamp=null; > public static ArrayList<String> namesArray=new > ArrayList<String>(); > > public void onCreate(Bundle savedInstanceState) { > super.onCreate(savedInstanceState); > Thread cThread= null; > try{ > cThread = new Thread(new ConnectSocket()); > cThread.start();} > catch (Exception e){ > Toast.makeText(getBaseContext(), > "Unable to start thread", > Toast.LENGTH_LONG).show(); > > } > Toast.makeText(getBaseContext(), > "Starting", > Toast.LENGTH_LONG).show(); > > try { > getFriendsList(); > } catch (Exception e) { > Toast.makeText(getBaseContext(), > "Unable to fetch friend list:"+e.getMessage(), > Toast.LENGTH_LONG).show(); > e.printStackTrace(); > } > try { > displayFriendsList(); > } catch (Exception e) { > Toast.makeText(getBaseContext(), > "Unable to display friend list:"+e.getMessage() > +e.getLocalizedMessage(), > Toast.LENGTH_LONG).show(); > e.printStackTrace(); > } > ConnectSocket socket = new ConnectSocket(); > > socket.sendData("ABCDEF"); > String k = socket.recieveData(); > Toast.makeText(getBaseContext(), > "Recieved from server:"+k, > Toast.LENGTH_LONG).show(); > > > > } > > > private void getFriendsList() { > > > String line[] = new String[3]; > line[0]= > "Abdul#Raqeeb#23.44#34.44#4.45"; > line[1]= > "Abdul#Azeez#33.44#44.44#5.45"; > line[2]= > "Kiral#Azeez#53.44#454.44#6.45"; > for(int k=0;k<=2;k++){ > StringTokenizer tokens=new > StringTokenizer(line[k],"#"); > try{ > while(tokens.hasMoreTokens()) > { > FName=tokens.nextToken(); > LName=tokens.nextToken(); > Latitude=tokens.nextToken(); > Longitude=tokens.nextToken(); > TimeStamp=tokens.nextToken(); > listOfFriends.add(new > MyFriend(FName,LName,Latitude,Longitude,TimeStamp)); > } > } > catch (Exception e){ > Toast.makeText(this, > "Some prob > here:"+e.getLocalizedMessage(), > > Toast.LENGTH_SHORT).show(); > e.printStackTrace(); > } > } > > > } > > > } > > [/code] > > The code related to the thread is > [code] > package com.getfriends; > > import java.io.BufferedReader; > import java.io.DataOutputStream; > import java.io.IOException; > import java.io.InputStreamReader; > import java.net.InetAddress; > import java.net.Socket; > > import android.util.Log; > > public class ConnectSocket implements Runnable{ > /** Called when the activity is first created. */ > > > public String fromServer=null; > public static BufferedReader inFromServer=null; > public static Socket clientSocket=null; > public InetAddress address =null; > public static DataOutputStream outToServer=null; > > > @Override > public void run(){ > > > try { > address = InetAddress.getByName("127.0.0.1"); > Log.d("TCP", "C: Connecting..."); > clientSocket = new Socket(address, 9999); > outToServer = new > DataOutputStream(clientSocket.getOutputStream()); > inFromServer = new BufferedReader(new > InputStreamReader(clientSocket.getInputStream())); > } catch (Exception e) { > System.out.println("Not Connected to the internet"); > } > > } > > public void sendData(String s){ > try { > if(s.equals(null)) s="hello"; > Log.d("TCP", "C: Sending..."); > outToServer.writeBytes(s+'#'); > outToServer.flush(); > } catch (IOException e) { > // TODO Auto-generated catch block > Log.d("TCP", "unable to send msg"); > e.printStackTrace(); > } > > } > > public String recieveData(){ > try { > fromServer = inFromServer.readLine(); > if(fromServer.equals(null)) fromServer="bad luck"; > } catch (IOException e) { > // TODO Auto-generated catch block > Log.d("TCP", "unable to send msg"); > e.printStackTrace(); > } > return fromServer; > > > } > > > } > [/code] > > Many thanks, > Raqeeb > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected]<android-developers%[email protected]> > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > > To unsubscribe, reply using "remove me" as the subject. > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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