@Override
        protected void onCreate(Bundle savedInstanceState) {
            requestWindowFeature(Window.FEATURE_NO_TITLE);
            super.onCreate(savedInstanceState);
            setContentView(R.layout.number_indicator_spinner);
            setCanceledOnTouchOutside(false);

            RelativeLayout content = (RelativeLayout) this
                    .findViewById(R.id.number_indicator_spinner_content);
            indicator = new Indicator(this.getContext());
            content.addView(indicator);

            numberIndicator = new TextView(getContext());
            numberIndicator.setTextColor(Color.WHITE);
            numberIndicator.setGravity(Gravity.CENTER);
            content.addView(numberIndicator);

            indicator.setLayoutParams(new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.FILL_PARENT,
                    RelativeLayout.LayoutParams.FILL_PARENT));
        }
Make a dark color to press effect

@return
MaterialDesignLibrary/MaterialDesign/src/main/java/com/gc/materialdesign/views/Slider.java