Well in order to help I need to know what is causing the NullPointerException. You need to set up a break point at the start of your code and step through(f5) Keep an eye on the code b/c at some point it will error out and the line of code it was on right before then is the one giving the issue.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of raqz Sent: Thursday, April 08, 2010 1:47 AM To: Android Developers Subject: [android-developers] Re: Trying to start a thread dedicated to sending and receiving data The errors are as below java.lang.NullPointerException at com.getFriends.ConnectSocket.sendData(ConnectSocket.java:43) I am not sure why its giving such an error. Please help. Thanks, Raqeeb On Apr 8, 1:41 am, "Tommy" <[email protected]> wrote: > What line does the debug catch the error? Have you stepped through to see > what line causes the exception to throw? > > -----Original Message----- > From: [email protected] > > [mailto:[email protected]] On Behalf Of raqz > Sent: Thursday, April 08, 2010 1:37 AM > To: Android Developers > Subject: [android-developers] Trying to start a thread dedicated to sending > and receiving data > > 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] > For more options, visit this group athttp://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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