How to bind an Activity to a Service and control a

Question

I'm trying to bind an Activity to a LocalService to interact with it. But in my Activity I am only able to make calls to methods defined in my LocalBinder and not in my LocalService. What am I doing wrong?

Not starting scratch I read another question and I have read a little how to code some sample code and my code resembles that sample code. Also I have been reading some of the Service Documentation for convenience here is a small quote from that section of the documentation:

"A service is "bound" when an application component binds to it by calling bindService(). A bound service offers a client-server interface that allows components to interact with the service, send requests, get results, and even do so across processes with interprocess communication (IPC). A bound service runs only as long as another application component is bound to it. Multiple components can bind to the service at once, but when all of them unbind, the service is destroyed."

But I can't do that. As mentioned above the best I can do is to have my Activity call methods defined in my LocalBinder. I have achieved nothing like the part highlighted in black above.

If it helps here are the relevant portions of my code.

LocalService to be bound to:

/**************************************************************************************************
 * Filename: LocalService.java
 * Project name: Local Service Sample
 * Application name: Local Service
 * Description: This file contains the LocalService (extends Service) for our Local Service app
 **************************************************************************************************/

package com.marie.localservicesample;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;
import android.widget.Toast;

public class LocalService extends Service {
    private NotificationManager mNM;

    // Unique Identification Number for the Notification.
    // We use it on Notification start, and to cancel it.
    private int NOTIFICATION = R.string.local_service_started;

    // just some arbitrary numbers for test purposes
    public static int statusCode = 99;
    public static  int emptyMsg = 549;

    // I get my Extras from onStartCommand and use in ServiceWorker() thread
    public static final String EXTRA_MAC = "com.marie.localservicesample.EXTRA_MAC";
    private String macString;

    public static final String EXTRA_MESSENGER = "com.marie.localservicesample.EXTRA_MESSENGER";
    private Messenger messenger;

    private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
    //private static final String macString = "00:06:66:02:D0:EC";

    Boolean stop_receive_data = false;

    // This is the object that receives interactions from clients.  See
    // RemoteService for a more complete example - or not because
    // this is a local service
    private final IBinder mBinder =  new LocalBinder();

    @Override
    public IBinder onBind(Intent intent) {
        Log.i("onBind", "called in LocalService" );
        Log.i("onBind", "intent: " + intent.toString());
        Log.i("onBind", "mBinder: " + mBinder);
        return mBinder;
    }

    @Override
    public void onCreate() {
        mNM = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

        // Display a notification about us starting.  We put an icon in the status bar.
        showNotification();
    }

    // Call this at the end of onStartCommand() after we got the Extras
    public void afterStartCommand() {
        Thread thr = new Thread(null, new ServiceWorker(), "LocalService");
        thr.start();  
    }

    /*
     * This is the ServiceWorker thread that passes messages to the handler defined in
     * the Controller activity.
     */
    class ServiceWorker implements Runnable
    {
        public void run() {
            // do background processing here... something simple
            Looper.prepare();

            BluetoothAdapter btAdapter = BluetoothAdapter.getDefaultAdapter();
            BluetoothDevice btDevice = btAdapter.getRemoteDevice(macString);
            BluetoothSocket btSocket = null;
            InputStream btIstream = null;
            OutputStream btOstream = null;
            try {
                btSocket = btDevice.createRfcommSocketToServiceRecord(MY_UUID);
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            try {
                btSocket.connect();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            try {
                btIstream = btSocket.getInputStream();
                btOstream = btSocket.getOutputStream();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            try {
                int data = btIstream.read();

                // reset the bluetooth device
                while (data != 63) {
                    Log.d("LocalService", "resetting bluetooth device");
                    btOstream.write('r');
                    data = btIstream.read();
                }

                StringBuffer strBuffer = new StringBuffer("");
                Boolean dataBegin = false;

                int ndxPlus = 0;

                while (data != -1) {
                    char printableB = (char) data;
                    if (data < 32 || data > 126) {
                        //printableB = ' ';
                    }               
                    //Log.d("LocalService", Character.toString(printableB) + "(" + data + ")");

                    if (data == 63) {
                        btOstream.write('$');
                        btOstream.write(',');
                    }
                    if (data == 45) {
                        btOstream.write('1');
                        btOstream.write(',');
                        dataBegin = true;
                    }
                    if (dataBegin == true) {
                        strBuffer = strBuffer.append(Character.toString(printableB));
                    }
                    if (data == 13) {
                        dataBegin = false;
                        //Log.d("LocalServiceDataString", strBuffer.toString());

                        // send data to the handler to plot the data
                        Message msg = Message.obtain();
                        msg.what = Controller.MESSAGE_MAC;
                        msg.obj = strBuffer;
                        try {
                            messenger.send(msg);
                        } catch (RemoteException e) {
                            e.printStackTrace();
                        }

                        strBuffer = new StringBuffer("");
                        if (ndxPlus < 0) {
                            btOstream.write('+');
                            ndxPlus++;
                        }
                    }

                    data = btIstream.read();
                    if (stop_receive_data) data = -1;

                }

            } catch (IOException e1) {
                e1.printStackTrace();
            }
            try {
                btSocket.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }

            LocalService.this.stopSelf();
            Looper.loop();
            // stop the service when done...
            // Or use the unbindBtn in the MainActivity class?
        }
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("LocalService", "Received start id " + startId + ": " + intent);

        Bundle extras = intent.getExtras();

        messenger = (Messenger)extras.get(EXTRA_MESSENGER);
        macString = extras.getString(EXTRA_MAC);

        afterStartCommand();

        // We want this service to continue running until it is explicitly
        // stopped, so return sticky.
        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        // Cancel the persistent notification.
        mNM.cancel(NOTIFICATION);
        stop_receive_data = true;
        // Tell the user we stopped.
        Toast.makeText(this, R.string.local_service_stopped, Toast.LENGTH_SHORT).show();
    }

    /**
     * Show a notification while this service is running.
     */
    private void showNotification() {
        // In this sample, we'll use the same text for the ticker and the expanded notification
        CharSequence text = getText(R.string.local_service_started);

        // Set the icon, scrolling text and timestamp
        Notification notification = new Notification(R.drawable.stat_sample, text, System.currentTimeMillis());

        // The PendingIntent to launch our activity if the user selects this notification
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, Controller.class), 0);

        // Set the info for the views that show in the notification panel.
        notification.setLatestEventInfo(this, getText(R.string.local_service_label), text, contentIntent);

        // Send the notification.
        mNM.notify(NOTIFICATION, notification);
    }
}

Activity that binds to LocalService:

/**************************************************************************************************
 * Filename: Binding.java
 * Project name: Local Service Sample
 * Application name: Local Service
 * Description: This file contains the Binding class for our Local Service application
 **************************************************************************************************/
package com.marie.localservicesample;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

/*
 * Example of binding and unbinding to the local service.
 * This demonstrates the implementation of a service which the client will
 * bind to, receiving an object through which it can communicate with the service.
 */

public class Binding extends Activity {
    private ILocalBinder mBoundService;
    private boolean mIsBound;

    private ServiceConnection mConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className, IBinder service) {
            // This is called when the connection with the service has been
            // established, giving us the service object we can use to
            // interact with the service.  Because we have bound to a explicit
            // service that we know is running in our own process, we can
            // cast its IBinder to a concrete class and directly access it.
            mBoundService = (ILocalBinder)service;

            int statusCode = mBoundService.getStatusCode();

            Log.d("Binding.java","called onServiceConnected. statusCode: " + statusCode);

            Toast.makeText(Binding.this, R.string.local_service_connected,
                    Toast.LENGTH_SHORT).show();
        }

        public void onServiceDisconnected(ComponentName className) {
            // This is called when the connection with the service has been
            // unexpectedly disconnected -- that is, its process crashed.
            // Because it is running in our same process, we should never
            // see this happen.
            mBoundService = null;

            Log.d("Binding", "called onServiceDisconnected");

            Toast.makeText(Binding.this, R.string.local_service_disconnected,
                    Toast.LENGTH_SHORT).show();
        }
    };

    void doBindService() {
        // Establish a connection with the service.  We use an explicit
        // class name because we want a specific service implementation that
        // we know will be running in our own process (and thus won't be
        // supporting component replacement by other applications).
        bindService(new Intent(Binding.this, LocalService.class), mConnection, Context.BIND_AUTO_CREATE);
        mIsBound = true;
    }

    void doUnbindService() {
        if (mIsBound) {
            int statusCode = mBoundService.getStatusCode();
            if (statusCode != 0) Log.d("doUnbindService", "Binding.java statusCode: " + statusCode);

            // Tell the user we did an unbind
            Toast.makeText(this, R.string.local_service_unbound, Toast.LENGTH_SHORT).show();

            // Detach our existing connection.
            unbindService(mConnection);
            mIsBound = false;
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.local_service_binding);

        // Watch for button clicks.
        Button button = (Button)findViewById(R.id.bind);
        button.setOnClickListener(mBindListener);
        button = (Button)findViewById(R.id.unbind);
        button.setOnClickListener(mUnbindListener);
    }

    private OnClickListener mBindListener = new OnClickListener() {
        public void onClick(View v) {
            doBindService();
        }
    };

    private OnClickListener mUnbindListener = new OnClickListener() {
        public void onClick(View v) {
            doUnbindService();
        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        doUnbindService();
    }
}    

My ILocalBinder and LocalBinder:

/**************************************************************************************************
 * Filename: ILocalBinder.java
 * Project name: Local Service Sample
 * Application name: Local Service
 * Description: This file contains an example interface for my LocalBinder
 **************************************************************************************************/

package com.marie.localservicesample;

public interface ILocalBinder {

    public int getStatusCode();
}

/**************************************************************************************************
 * Filename: LocalBinder.java
 * Project name: Local Service Sample
 * Application name: Local Service
 * Description: This file contains the LocalBinder class for our Local Service application
 **************************************************************************************************/

package com.marie.localservicesample;

import android.os.Binder;

import com.marie.localservicesample.LocalService;

/**
 * Class for clients to access.  Because we know this service always
 * runs in the same process as its clients, we don't need to deal with
 * IPC.
 */
public class LocalBinder extends Binder implements ILocalBinder {
    @Override
    public int getStatusCode() {
        return LocalService.statusCode;
    }

}

Thanks!

Answer 1

See the local service example.

Just copy the binder class code they have into your service instead of making a separate file for it: (inside the LocalService class declaration)

public class LocalService {
    // This is the object that receives interactions from clients.  See
    // RemoteService for a more complete example.
    private final IBinder mBinder = new LocalBinder();

    /**
     * Class for clients to access.  Because we know this service always
     * runs in the same process as its clients, we don't need to deal with
     * IPC.
     */
    public class LocalBinder extends Binder {
        LocalService getService() {
            return LocalService.this;
        }
    }

    ...
}

and then:

public void onServiceConnected(ComponentName className, IBinder service) {
    // This is called when the connection with the service has been
    // established, giving us the service object we can use to
    // interact with the service.  Because we have bound to a explicit
    // service that we know is running in our own process, we can
    // cast its IBinder to a concrete class and directly access it.
    mBoundService = ((LocalService.LocalBinder)service).getService();

Now you can access your service directly using mBoundService.