Local services vs. Remote Services Local services are used by components in the same process (or vm?)

Local services vs. Remote Services

• 
  Local services are used by components in the same process (or VM?)
  
• 
  Remote services are accessible to other processes.
  
  • 
    The interface for remote services is more complicated than for local services
    
• 
  Examples
  
  • 
    Audio player
    
    • 
      The GUI is an activity
      
    • 
      The player is a local service that keeps on running although the GUI is no longer running (e.g., the GUI is not in focus or was “closed”)
      
  • 
    Map tracker: something that marks your path on a map
    
    • 
      The gui is an activity
      
    • 
      Recording the locations is in a local service, so that the path is kept up to date even though the activity is no longer running
      
  • 
    Fancy location provider: something that is better than the GPS based location provider built into the android
    
    • 
      This should be a remote service so that different applications can use it. If it was a local service, then each app would have to have its own copy
      

Local service (video)

• 
  There are two parts, the service and the activity that uses the service
  
• 
  Start a new project called FunWithLocalServices as usual
  
• 
  Add a new class MyService, but derive it from android.app.Service
  

Add:

public void onCreate() {

super.onCreate();

Log.d("MyService","Created");

}

Add:

public void onDestroy() {

super.onDestroy();

Log.d("MyService","Destroyed");

}

In manifest, either

or

in application tab, in Application Nodes, add Service. Set name = MyService

In onCreate add:

Log.e("FunWithLocalServices","Starting Service");

startService(new Intent(this, MyService.class));

int myCnt = 0;

MyService (video)

Add:

We want to provide access to MyServices member variables and functions. A binder will do this:

private final Binder binder = new LocalBinder();

public class LocalBinder extends Binder {

MyService getService() {

Log.d("MyService","localbinder");

return MyService.this;

}

}

Save

Add variable:

private MyService myService = null;

And

@Override

public void onServiceConnected(ComponentName className, IBinder rawBinder) {

myService = ((MyService.LocalBinder)rawBinder).getService();

}

@Override

myService = null;

}

};
In onCreate add:

At the end of onDestroy add:

unbindService(connectionToMyService);

FunWithLocalServices continued

The myService variable provides access to MyServices. Let’s use it

Add button and button listener:

Button button = (Button)findViewById(R.id.Button01);

button.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

Log.e("MyLocalSERVICE","val="+myService.cnt+" mycnt= "+myCnt);

myService.cnt++;

myCnt++; });