Displaying processed image on screen

edit

you can convert it to a Bitmap, and draw it to an ImageView:

public void helloworld() {
        // make a mat and draw something
        Mat m = Mat.zeros(100,400, CvType.CV_8UC3);
        Core.putText(m, "hi there ;)", new Point(30,80), 
                Core.FONT_HERSHEY_SCRIPT_SIMPLEX, 2.2, new Scalar(200,200,0),2);

        // convert to bitmap:
        Bitmap bm = Bitmap.createBitmap(m.cols(), m.rows(),Bitmap.Config.ARGB_8888);
        Utils.matToBitmap(m, bm);

        // find the imageview and draw it!
        ImageView iv = (ImageView) findViewById(R.id.imageView1);
        iv.setImageBitmap(bm);
}