Using bitmap in external dialog Imageview

As I can assign a bitmap of a previously selected image, a ImageView an external Layout Dialog .. I have this code, which when not assign the layout to strip findViewById returns error, if assign it (which is what I think the problem is) simply nothing happens, not display the image.

Method that selects image gallery

    public void selImagen(View v){
    Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.INTERNAL_CONTENT_URI);
    int code = SELECT_PICTURE;
    startActivityForResult(intent, code);
}

method that creates a bitmap image selected and displayed on a imageview

@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
   //The problem is here I think, if so OTHERWISE INDICATE THAT BELONGS TO THIS LAYOUT IMAGEVIEW

    LayoutInflater li = LayoutInflater.from(this);
    View prompt = li.inflate(R.layout.prod_new_modal, null);

    Uri selectedImage = data.getData();
    InputStream is;
    try {
        is = getContentResolver().openInputStream(selectedImage);
        BufferedInputStream bis = new BufferedInputStream(is);
        final Bitmap bitmap = BitmapFactory.decodeStream(bis);
        ImageView imageview = (ImageView)findViewById(R.id.imgView);
        imageview.setImageBitmap(bitmap);

    } catch (FileNotFoundException e) {

    } catch (IOException e) {
        e.printStackTrace();
    }
}