How to take pictures from the camera without preview when my app starts?

Now all I want is an app that just takes the picture from the camera upon launching. No layout, no camera preview...nothing, just a simple app icon to launch the app. Once launched the camera should take the picture.

Here is the preview image, that i do not want to appear in my app. I just want to eanble my app to click the take picture button encircled in the image here:

Once the picture is taken then I need to save it in my photo gallery.

Can someone guide me here? Thanks

Here is some code that I have tried on emulator and device.

import java.io.IOException;
import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;

public class Main extends Activity implements SurfaceHolder.Callback{

    private Camera camera;
     private ImageButton cameraClick;
     private SurfaceHolder mHolder; 

    /** Called when the activity is first created. */
     @Override
     public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      SurfaceView surfaceView = (SurfaceView)findViewById(R.id.surfaceView1);
      mHolder = surfaceView.getHolder();
      mHolder.addCallback(this);
      mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);  

      cameraClick = (ImageButton) findViewById(R.id.cameraClick);
      cameraClick.setOnClickListener( new OnClickListener() {
       public void onClick(View v)
       {
            camera.takePicture(shutterCallback, rawCallback,jpegCallback);
       }
      });  





      }

     // Handles when shutter open
     ShutterCallback shutterCallback = new ShutterCallback()
     {
      public void onShutter()
      {   

      }
     };

     /** Handles data for raw picture */
     PictureCallback rawCallback = new PictureCallback()
     {
      public void onPictureTaken(byte[] data, Camera camera)
      {   

      }
     }; 

     /** Handles data for jpeg picture */
     PictureCallback jpegCallback = new PictureCallback()
    {
      public void onPictureTaken(byte[] data, Camera camera)
    {
       // we do something using return byte[] of taken image.
      }
     };

     @Override
     public void surfaceChanged(SurfaceHolder holder,int format,int width,int height)
    {

      // Set camera preview size,orientation,rotation using parameters 

    Camera.Parameters parameters = camera.getParameters();
            parameters.set("orientation", "portrait");
            camera.setParameters(parameters);
             camera.startPreview();       

     }

     @Override
     public void surfaceCreated(SurfaceHolder holder)
    {
      camera = Camera.open();
             try {
        camera.setPreviewDisplay(holder);
       }
    catch (IOException e)
    {
        e.printStackTrace();
       }

     }

     @Override
     public void surfaceDestroyed(SurfaceHolder holder)
    {
      camera.stopPreview();
             camera.release();
            camera = null; 

     }

}

Now I am able to hear the picture click on the button click both on the emulator and the device. Now I want to save the picture as well. Any clue?