MainActivity.java

package github.nisrulz.boundservices;

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.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    Messenger myService = null;
    boolean isBound;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        // Bind to Service
        Intent intent = new Intent(getApplicationContext(), MyBoundService.class);
        bindService(intent, myServiceConnection, Context.BIND_AUTO_CREATE);


        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Send Message
                sendMessage();
            }
        });
    }

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

        // Unbind from service so as to not leak the service connection
        unbindService(myServiceConnection);
    }

    void sendMessage() {
        if (!isBound) return;

        Message msg = Message.obtain();

        Bundle bundle = new Bundle();
        bundle.putString("data", "Hello World!");

        msg.setData(bundle);
        try {
            myService.send(msg);
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }

    // Service Connection
    private ServiceConnection myServiceConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className,
                                       IBinder service) {
            myService = new Messenger(service);
            isBound = true;
        }

        public void onServiceDisconnected(ComponentName className) {
            myService = null;
            isBound = false;
        }
    };

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}