Remove commented out code.

            }

            final MainActivity main_activity = (MainActivity)this.getContext();

			/*final Button prev_button = new Button(this.getContext());

			//prev_button.setBackgroundResource(R.drawable.exposure);

			prev_button.setBackgroundColor(Color.TRANSPARENT); // workaround for Android 6 crash!

			prev_button.setText("<");

			this.addView(prev_button);*/

            LinearLayout ll2 = new LinearLayout(this.getContext());

            ll2.setOrientation(LinearLayout.HORIZONTAL);