Basic Socket Problem

scottk9876 · by **scottk9876** » Tue Jul 03, 2012 12:17 am

[The pic at the bottom shows the result on the emulator for running the app]

I am developing a network application that exchanges xml data from an android app to a remote server. The server receives xml requests from the apps, processes them, and returns an xml result.

My goal is to overcome the technical hurdles by establishing a simple proof-of-concept server and app pair that can talk to each other through a TCP socket connection.

I have Windows 7 operating with IIS that has a server on port 23 that receives an xml request, displays the request for me to see (on a memo field), and responds with a string back to the client. I know this server works (written with Delphi) because I have a delphi client that sends an xml request that gets displayed, and receives the output xml from the server that it, in turn, displays.

I wish to create an andoid app using Eclipse that duplicates the client functionality - namely, it opens a socket connection with the server, sends pre-set xml (just a string) and receives the resulting xml from the server. I can’t even get the connection to work. I am new to android development so please bear with me. I will provide you with whatever you need to help.

Here is the android manifest:

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Using xml Syntax Highlighting

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.client"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-sdk android:minSdkVersion="15" />
    <uses-permission android:name="android.permission.INTERNET" />
  
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".ClientTestActivity"
            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>
 
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Here is the Java Code:

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Using java Syntax Highlighting

package com.example.client;
 
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
 
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
 
public class ClientTestActivity extends Activity {
        
        // Define our variables
        SocketAddress sockaddr; // Our socket address
        Socket my_socket;                       // Our Socket to send xml data
        TextView display_txt;   // The display view we use to communicate results
        
    /** Called when the activity is first created. */
[syntax="java"][/syntax]    @Override
    public void onCreate(Bundle savedInstanceState) {  
 
        /** Default constructors */
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        display_txt = (TextView)findViewById(R.id.textView1);
        
        /**  Protect against exceptions */
        try {
                
                /**  define the socket address. 10.0.2.2 should map to "Localhost" */
                        SocketAddress sockaddr = new InetSocketAddress("10.0.2.2", 23);
                        
                        /**  Instantiate and connect the socket */
            my_socket = new Socket();
                        my_socket.connect( sockaddr );
                        
                        
                } catch (IOException e) {
                        
                                /**  Report an exception encountered */
                                display_txt.setText("Nasty Error");
                                
                } finally {
                        
                        /** Catch any exception thrown from closing the socket */
                        try {
                                
                                /** Close our socket and report results */
                                my_socket.close();
                                display_txt.setText("Connected Okay!");
                                
                        } catch (IOException e) {
                                
                                /** Display the error trying to close */
                                display_txt.setText("Could not close socket.");
                                
                        }
                }
        
    }
} 
Parsed in 0.036 seconds,  using GeSHi 1.0.8.4

When I run the app, I don't get the expected error messages or "Connected Okay!". I simply get the emulator stating "Unfortunately, Client_Socket has stopped".

Thank you VERY MUCH, in advance, for your time and help.

Scott

Basic Socket Problem

Basic Socket Problem

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