hi use this code and hopefully this works
basically your image view is null so first inintiallise it
ImageView img= new ImageView();
img=(ImageView) rrr.getChildAt(0);
img.setRotation(90);
img.setDrawingCacheEnabled(true);
img.buildDrawingCache();
if(img.isDrawingCacheEnabled()){
Bitmap bitmap =img.getDrawingCache(true);
}img.destroyDrawingCache();
img.setDrawingCacheEnabled(false);
ByteArrayOutputStream bao = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100,
bao);
int width = bitmap.getWidth();
int height = bitmap.getHeight();
Matrix matrix = new Matrix();
matrix.postRotate(90);
Bitmap rotatedBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
BitmapDrawable bmd = new BitmapDrawable(rotatedBitmap);
rrr.removeViewAt(0);
ImageView img_new=new ImageView(ImageSlideShow.this);
img_new.setImageDrawable(bmd);
img_new.setScaleType(ScaleType.CENTER);
rrr.addView(img_new, new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));