Question

I am currently having trouble connecting to my webservice on android. I am using a Jetty web service and building it using ANT. On my laptop it works perfectly and displays items from my database. However it won’t seem to connect on my Android application. Attached is the code and LOGCAT report.

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.TextView;
public class Android2Servlet extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dbtest);
TextView txtresp = (TextView)findViewById(R.id.servlet_response);

String url = "http://(MY LAPTOPS IP):8085/DB";
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
try{
System.out.println("About to execute");
HttpResponse response = client.execute(request);
String helpedResp=HttpUnpack.request(response); 
System.out.println(helpedResp); 
txtresp.setText(helpedResp);
System.out.println(response);
}catch(Exception ex){
txtresp.setText("Failed!");
ex.printStackTrace();
}
} }

The HTTP Unpack File

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
public class HttpUnpack {
public static String request(HttpResponse response){
String result = "";
try{ InputStream in = response.getEntity().getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder str = new StringBuilder();
String line = null;
while((line = reader.readLine()) != null){
str.append(line + "\n");
}
in.close();
result = str.toString();
}catch(Exception ex){
result = "Error retrieving response";
}
return result;
}
}

The HTTP Unpack and the Android2Servlet do not cause any errors, however the text box only returns “Failed!”.

LOGCAT file

W/System.err(1282): android.os.NetworkOnMainThreadException
W/System.err(1282):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
W/System.err(1282):     at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
W/System.err(1282):     at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
W/System.err(1282):     at libcore.io.IoBridge.connect(IoBridge.java:112)
W/System.err(1282):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
W/System.err(1282):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
W/System.err(1282):     at java.net.Socket.connect(Socket.java:842)
W/System.err(1282):     at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
W/System.err(1282):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
W/System.err(1282):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
W/System.err(1282):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
W/System.err(1282):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
W/System.err(1282):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
W/System.err(1282):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
W/System.err(1282):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
W/System.err(1282):     at myFood.myFood.Android2Servlet.onCreate(Android2Servlet.java:24)
W/System.err(1282):     at android.app.Activity.performCreate(Activity.java:4465)
W/System.err(1282):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
W/System.err(1282):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
W/System.err(1282):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
W/System.err(1282):     at android.app.ActivityThread.access$600(ActivityThread.java:123)
W/System.err(1282):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
W/System.err(1282):     at android.os.Handler.dispatchMessage(Handler.java:99)
W/System.err(1282):     at android.os.Looper.loop(Looper.java:137)
W/System.err(1282):     at android.app.ActivityThread.main(ActivityThread.java:4424)
W/System.err(1282):     at java.lang.reflect.Method.invokeNative(Native Method)
W/System.err(1282):     at java.lang.reflect.Method.invoke(Method.java:511)
W/System.err(1282):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
W/System.err(1282):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
W/System.err(1282):     at dalvik.system.NativeStart.main(Native Method)

Any response would be greatly helpful.

Regards.

EDIT:

I have now removed the network access and put it in another Java class. And called it form another class. And it is still returning the same errors. Any other advice?

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
public class androidconnectors {

    public static final String main(String args[]) throws Exception {


String txtresp = "";
try{
    String url = "http://(LAPTOPS IP):8085/Hello";
    HttpClient client = new DefaultHttpClient();
    HttpGet request = new HttpGet(url);
System.out.println("About to execute");
HttpResponse response = client.execute(request);
String helpedResp=HttpUnpack.request(response); // Http Unpack is not part of
System.out.println(helpedResp); // of HttpClient library
txtresp =(helpedResp);
System.out.println(response);
}catch(Exception ex){
    ex.printStackTrace();
}
return txtresp;
}
}

And the android class.

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class Settings extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dbtest);
        Button mybutton = (Button) findViewById(R.id.buttonpress);
        mybutton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                TextView txtresp = (TextView)findViewById(R.id.servlet_response);
            String[] args = null;
            try {
                String x = androidconnectors.main(args);
                txtresp.setText(x);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                txtresp.setText("Failed");
            }

            }
        });
}
}

Answer 1

It would seem, based on a quick google search, that since Honeycomb you are not supposed to execute network access on your app’s main thread (to improve responsiveness).

Create another thread for network access as suggested here.