private void applyBackgroundColor(TypedArray attrs, int attributeIndex, View targetView) {
        if (attrs.hasValue(attributeIndex)) {
            final int color = attrs.getColor(attributeIndex, 0);
            targetView.setBackgroundColor(color);
        }
    }
Sets the padding to be used for the number pad buttons.

@param padding padding in pixels
android/third_party/time-duration-picker/src/main/java/mobi/upod/timedurationpicker/TimeDurationPicker.java