如何将服务对象传递给Android中的子类？

Question

I'm developing an app, which gets data from web and writes it back to web. For that I was using AsyncTask, but those requests weren't optimized, so I had to authenticate user, on every request. Now I want to use Service for holding the connection to backend and to do requests without needing to authenticate the user on every requests.

I'm having trouble to send this service object to subactivity without creating an new instance and nulling all the values I need from the service. So how to do it without osing values ?

Here is my service:

public class LasteMVService extends Service {

    private ArrayList<WorkSheet> workSheetArrayList;
    private SpreadSheet selectedSpeadSheet;
    private static String LOG_TAG = "LasteMVService";
    private IBinder mBinder = new MyBinder();


    @Override
    public void onCreate() {
        super.onCreate();
        new Thread(new Task()).start();

        Log.v(LOG_TAG, "in onCreate");

    }


    @Override
    public IBinder onBind(Intent intent) {
        Log.v(LOG_TAG, "in onBind");
        return mBinder;
    }

    @Override
    public void onRebind(Intent intent) {
        Log.v(LOG_TAG, "in onRebind");
        super.onRebind(intent);

    }


    public SpreadSheet getSelectedSpeadSheet() {
        return selectedSpeadSheet;
    }

    public ArrayList<WorkSheet> getWorkSheetArrayList() {
        return workSheetArrayList;
    }

    @Override
    public void onDestroy() {
        Log.v(LOG_TAG, "in onDestroy");
        super.onDestroy();
    }

    public class MyBinder extends Binder {
        public LasteMVService getService() {
            return LasteMVService.this;
        }
    }

    class Task implements Runnable {

        @Override
        public void run() {
            synchronized (this){
            AndroidAuthenticator androidAuthenticator = new AndroidAuthenticator(getApplicationContext());
            SpreadSheetFactory spf = SpreadSheetFactory.getInstance(androidAuthenticator);
            ArrayList<SpreadSheet> sheets = spf.getSpreadSheet("Stardiprotokoll", true);
            if (sheets != null) {
                final SpreadSheet spreadSheet = sheets.get(0);
                selectedSpeadSheet = spreadSheet;
                ArrayList<WorkSheet> workSheet = spreadSheet.getAllWorkSheets();
                workSheetArrayList = workSheet;
            }
        }
        }
    }
}

And here is where I bind it with BaseActivity:

public class BaseActivity extends AppCompatActivity {


        protected LasteMVService lasteMVService;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            lasteMVService = ((LasteMVApplication) getApplicationContext()).getLasteMVService();
            if(lasteMVService == null){
                ((LasteMVApplication) getApplicationContext()).initApp();
                lasteMVService = ((LasteMVApplication) getApplicationContext()).getLasteMVService();
                Util.restartApp(this, true);
            }


        }

        @Override
        protected void onStart() {
            super.onStart();
            Intent intent = new Intent(BaseActivity.this,LasteMVService.class);
            startService(intent);
bindService(intent,serviceConnection,BIND_AUTO_CREATE);


        }
      protected ServiceConnection serviceConnection = new ServiceConnection() {
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
                LasteMVService.MyBinder myBinder = (LasteMVService.MyBinder) service;
                lasteMVService = myBinder.getService();

            }

            @Override
            public void onServiceDisconnected(ComponentName name) {

            }

        };

My question is how to get the same instance of the service in some of the subactivities of BaseActivity?

Answer 1

Okay so you need a service object, Scratch getting the object's reference from base activity rather create a singleton class that is globally accessible throughout your application.. The source code to help you is below

public class Common extends Application {

private Service mService; //Service Object from your class that extends service.
private Context mContext;

public Service getService(){
    return mService;
}
public void setService(Service service){
    mService = service;
}



@Override
public void onCreate() {
    super.onCreate();
    //Gets the context associated with the whole application
    mContext = getApplicationContext();
}
}


public class Service extends Service{

private Common mApp;
private Context mContext;


//Instantiate the Common Object from the singleton class within on create.
@Override
public void onCreate() {
    super.onCreate();
    mContext = getApplicationContext();

    mApp = (Common) getApplicationContext();
    mApp.setService(this);

    }

 }

  //Now to use it in your base Activity

public class BaseActivity extends AppCompatActivity{

private Common mApp;
private Service mService;

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

        mApp = (Common) mContext.getApplicationContext();

        //To use the service you would simply use:

        mService = mApp.getService()./*Some public method defined in your service*/;



    }


}