如何将位图从服务发送到Java，Android中的main？

Question

I'm making a service in my application to download images, that's unclear for me how can i send result (bitmap) from service to a main activity. Can I do that? Or in service there is only a possibitlity to save downloaded image somewhere and send only useless messages?

Answer 1

Try binding from the activity to the service and then pass the instance of the activity to the service. In this case you can pass bitmap from a service to the activity. However, you need to be real careful not introduce memory leaks

Something like this:

class TestActivity extends Activity {
    private BitmapService mBitmapService;
    private final ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName componentName,
                                       IBinder iBinder) {
            BitmapService.BitmapServiceBinder mBinder = (BitmapService.BitmapServiceBinder) iBinder;
            mBitmapService = mBinder.getBitmapService();
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {
        }
    };

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        bindService(new Intent(this, XMLDownloaderService.class), mServiceConnection, BIND_AUTO_CREATE);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(this.mServiceConnection);
    }
}

Your Service Side:

public class BitmapService extends BitmapService {

    public class BitmapServiceBinder extends Binder {
        public BitmapService getBitmapService() {
             return BitmapService.this;
        }
    }

     public BitmapService() {
        super("BitmapService");
     }

     @Override
     public IBinder onBind(Intent intent) {
         return mBinder;
     }

     @Override
     public void onCreate() {
          super.onCreate();
           if (mBinder == null) {
               mBinder = new BitmapServiceBinder();
           }
     }
}

Answer 2

Bitmap implements Parcelable , so you could always pass it in the intent:

Intent intent = new Intent(this, NewActivity.class);
intent.putExtra("BitmapImage", bitmap);

and retrieve it on the other end:

Intent intent = getIntent();
Bitmap bitmap = (Bitmap) intent.getParcelableExtra("BitmapImage");

If the bitmap exists as a file or a resource, its is always better to pass the URI or ResourceID of the bitmap and not the bitmap itself. Passing the entire bitmap requires a lot of memory. Passing the URL requires very little memory and allows each activity to load and scale the bitmap as they need it.

Answer pullout from: How can I pass a Bitmap object from one activity to another