Android: Overlay on Android Camera Preview

You can use SurfaceView and create a CustomView that will open the camera and you can adjust its size in the xml accordingly. Below is a pseudo code.

Create a class that extends SurfaceView and open camera inside that

CapturePreview.java

public class CapturePreview extends SurfaceView implements SurfaceHolder.Callback{

    public static Bitmap mBitmap;
    SurfaceHolder holder;
    static Camera mCamera;

    public CapturePreview(Context context, AttributeSet attrs) {
        super(context, attrs);

        holder = getHolder();
        holder.addCallback(this);
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

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

        Camera.Parameters parameters = mCamera.getParameters();
        parameters.getSupportedPreviewSizes();
        mCamera.setParameters(parameters);
        mCamera.startPreview();
    }
    @Override
    public void surfaceCreated(SurfaceHolder holder) {

        try {
            mCamera = Camera.open();
            mCamera.setPreviewDisplay(holder);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        mCamera.stopPreview();
        mCamera.release();
    }
    /***
     * 
     *  Take a picture and and convert it from bytes[] to Bitmap.
     *  
     */
    public static void takeAPicture(){  

        Camera.PictureCallback mPictureCallback = new PictureCallback() {
            @Override
            public void onPictureTaken(byte[] data, Camera camera) {

                BitmapFactory.Options options = new BitmapFactory.Options();
                mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length, options);
            }
        };
        mCamera.takePicture(null, null, mPictureCallback);
    }
}

Now you have to include the view that you created using SurfaceView in your xml like this

main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">

  <FrameLayout 
  android:id="@+id/mySurfaceView"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content">

  <com.cam.CapturePreview 
  android:layout_width="fill_parent"
  android:layout_height="wrap_content">
  </com.cam.CapturePreview>

  </FrameLayout>

  <LinearLayout 
  android:layout_below="@id/mySurfaceView" 
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:layout_centerInParent="true"
  android:gravity="center">

  <ImageView android:id="@+id/myImageView" 
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:src="https://stackoverflow.com/questions/7466336/@drawable/icon"/>
  </LinearLayout>  

</RelativeLayout>

Now you can use this main.xml in any Acitivty that will open a camera with a ImageView.
Thanks….