Services

    package="com.szy.service"

    android:versionCode="1"

    <application

        android:icon="@drawable/ic_launcher"

        <activity

            android:name=".MainActivity"

            <intent-filter>

            </intent-filter>

        </activity>

    </application>

</manifest>

<resources>

</resources>

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.Handler;

import android.os.IBinder;

import android.os.Message;

import android.os.Messenger;

import android.os.RemoteException;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

public class MainActivity extends Activity {

    Button btnBind, btnUnbind;

    TextView textStatus, textStrValue;

    Messenger mService = null;

    boolean mIsBound;

    final Messenger mMessenger = new Messenger(new IncomingHandler());

    String s = "";

    class IncomingHandler extends Handler {

        @Override

        public void handleMessage(Message msg) {

            switch (msg.what) {

            case MyService.MSG_SET_STRING_VALUE:

                String str1 = msg.getData().getString("str1");

                s += str1;

                textStrValue.setText("Coming Message: " + s);

                break;

            default:

                super.handleMessage(msg);

            }

        }

    }

    private ServiceConnection mConnection = new ServiceConnection() {

        public void onServiceConnected(ComponentName className, IBinder service) {

            mService = new Messenger(service);

            textStatus.setText("Attached.");

            try {

                Message msg = Message.obtain(null, MyService.MSG_REGISTER_CLIENT);

                msg.replyTo = mMessenger;

                mService.send(msg);

            } catch (RemoteException e) {

                // In this case the service has crashed before we could even do anything with it

            }

        }

        public void onServiceDisconnected(ComponentName className) {

            // This is called when the connection with the service has been unexpectedly disconnected - process crashed.

            mService = null;

            textStatus.setText("Disconnected.");

        }

    };

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        btnBind = (Button)findViewById(R.id.btnBind);

        btnUnbind = (Button)findViewById(R.id.btnUnbind);

        textStatus = (TextView)findViewById(R.id.textStatus);

        textStrValue = (TextView)findViewById(R.id.textStrValue);

        btnBind.setOnClickListener(btnBindListener);

        btnUnbind.setOnClickListener(btnUnbindListener);

        CheckIfServiceIsRunning();

    }

    private void CheckIfServiceIsRunning() {

        //If the service is running when the activity starts, we want to automatically bind to it.

        if (MyService.isRunning()) {

            doBindService();

        }

    }

    private OnClickListener btnBindListener = new OnClickListener() {

        public void onClick(View v){

            doBindService();

        }

    };

    private OnClickListener btnUnbindListener = new OnClickListener() {

        public void onClick(View v){

            doUnbindService();

        }

    };

    void doBindService() {

        bindService(new Intent(this, MyService.class), mConnection, Context.BIND_AUTO_CREATE);

        mIsBound = true;

        textStatus.setText("Binding.");

    }

    void doUnbindService() {

        if (mIsBound) {

            // If we have received the service, and hence registered with it, then now is the time to unregister.

            if (mService != null) {

                try {

                    Message msg = Message.obtain(null, MyService.MSG_UNREGISTER_CLIENT);

                    msg.replyTo = mMessenger;

                    mService.send(msg);

                } catch (RemoteException e) {

                    // There is nothing special we need to do if the service has crashed.

                } 

            }

            // Detach our existing connection.

            unbindService(mConnection);

            mIsBound = false;

            textStatus.setText("Unbinding.");

        }

    }

    @Override

    protected void onDestroy() {

        super.onDestroy();

        try {

            doUnbindService();

        } catch (Throwable t) {

            Log.e("MainActivity", "Failed to unbind from the service", t);

        }

    }

}

import java.util.ArrayList;

import java.util.Timer;

import java.util.TimerTask;

import android.app.Notification;

import android.app.NotificationManager;

import android.app.PendingIntent;

import android.app.Service;

import android.content.Intent;

import android.os.Bundle;

import android.os.Handler;

import android.os.IBinder;

import android.os.Message;

import android.os.Messenger;

import android.os.RemoteException;

import android.util.Log;

public class MyService extends Service {

    private NotificationManager nm;

    private Timer timer = new Timer();

    private int counter = 0;

    private static boolean isRunning = false;

    int mValue = 0; // Holds last value set by a client.

    static final int MSG_REGISTER_CLIENT = 1;

    static final int MSG_UNREGISTER_CLIENT = 2;

    static final int MSG_SET_STRING_VALUE = 4;

    final Messenger mMessenger = new Messenger(new IncomingHandler()); // Target we publish for clients to send messages to IncomingHandler.

    String sendText = "Hello World!";

    Messenger client = null;

    @Override

    public IBinder onBind(Intent intent) {

        return mMessenger.getBinder();

    }

    class IncomingHandler extends Handler { // Handler of incoming messages from clients.

        @Override

        public void handleMessage(Message msg) {

            switch (msg.what) {

            case MSG_REGISTER_CLIENT:

                     client = msg.replyTo;

                break;

            case MSG_UNREGISTER_CLIENT:

                     client = null;

                break;

            default:

                super.handleMessage(msg);

            }

        }

    }

    private void sendMessageToUI(char intvaluetosend) {

            try {

                Bundle b = new Bundle();

                b.putString("str1", "" + intvaluetosend);

                Message msg = Message.obtain(null, MSG_SET_STRING_VALUE);

                msg.setData(b);

                client.send(msg);

            } catch (RemoteException e) {

                     client = null;

            }

    }

    @Override

    public void onCreate() {

        super.onCreate();

        Log.i("MyService", "Service Started.");

        showNotification();

        timer.scheduleAtFixedRate(new TimerTask(){ public void run() {onTimerTick();}}, 0, 1000L);

        isRunning = true;

    }

    private void showNotification() {

        nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

        // In this sample, we'll use the same text for the ticker and the expanded notification

        CharSequence text = getText(R.string.service_started);

        String text2 = "send Hello World!";

        // Set the icon, scrolling text and timestamp

        Notification notification = new Notification(R.drawable.ic_launcher, text2, System.currentTimeMillis());

        // The PendingIntent to launch our activity if the user selects this notification

        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);

        // Set the info for the views that show in the notification panel.

        //notification.setLatestEventInfo(this, getText(R.string.service_label), text, contentIntent);

        notification.setLatestEventInfo(this, "Send Hello World", text2, contentIntent);

        // Send the notification.

        // We use a layout id because it is a unique number.  We use it later to cancel.

        nm.notify(R.string.service_started, notification);

    }

    public static boolean isRunning()

    {

        return isRunning;

    }

    private void onTimerTick() {

        Log.i("TimerTick", "Timer doing work." + counter);

        try {

            if(counter == (sendText.length()))

            {

                     counter = 0;

            }

            sendMessageToUI(sendText.charAt(counter));

            counter ++;

        } catch (Throwable t) { //you should always ultimately catch all exceptions in timer tasks.

            Log.e("TimerTick", "Timer Tick Failed.", t);           

        }

    }

    @Override

    public void onDestroy() {

        super.onDestroy();

        if (timer != null) {

                 timer.cancel();

        }

        counter = 0;

        nm.cancel(R.string.service_started); // Cancel the persistent notification.

        Log.i("MyService", "Service Stopped.");

        isRunning = false;

}