override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val galleries = ArrayList<Gallery>()
    galleries.add(Gallery(1, "Gallery 1", "", android.R.color.holo_green_light))
    galleries.add(Gallery(2, "Gallery 2", "", android.R.color.holo_red_light))
    galleries.add(Gallery(3, "Gallery 3", "", android.R.color.holo_blue_light))
    galleries.add(Gallery(4, "Gallery 4", "", android.R.color.holo_orange_light))
    galleries.add(Gallery(5, "Gallery 5", "", android.R.color.holo_purple))

    val galleryPagerAdapter = GalleryPagerAdapter(supportFragmentManager, vpGallery).apply {
        setItems(galleries)
    }

    vpGallery?.apply {
        adapter = galleryPagerAdapter
        addOnPageChangeListener(galleryPagerAdapter)
        setCurrentItem(1, false)
    }

    val pageSize = galleries.size
    counter.text = ("1/$pageSize")

    vpIndicator?.apply {
        setupWithViewPager(vpGallery, galleries.size)
        addOnPageChangeListener(object : ViewPager.OnPageChangeListener {
            override fun onPageScrollStateChanged(state: Int) {}

            override fun onPageScrolled(position: Int, positionOffset: Float,
                                        positionOffsetPixels: Int) {
            }

            override fun onPageSelected(position: Int) {
                counter.text = ("$position/$pageSize")
            }
        })
    }
}

override fun onDestroy() {
    super.onDestroy()
    vpIndicator.cleared()
}

class GalleryPagerAdapter(fm: FragmentManager, viewPager: ViewPager) : LooperFragmentStatePagerAdapter<Gallery>(fm, viewPager) {

    override fun getItem(oldPosition: Int, newPosition: Int): Fragment {
        return GalleryFragment.newInstance(content[newPosition])
    }
}

@Parcelize
data class Gallery(
        var id: Int,
        var name: String,
        var image: String
) : Parcelable

class GalleryFragment : Fragment() {

	override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
	                          savedInstanceState: Bundle?): View? {
		return inflater.inflate(R.layout.fragment_gallery, container, false)
	}

	override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
		super.onViewCreated(view, savedInstanceState)
		arguments?.getParcelable<Gallery>(Gallery::class.java.simpleName)
				?.let { gallery ->
					context?.let {
						rootView.setBackgroundColor(ContextCompat.getColor(it, gallery.backgroundColor))
					}
					tvMessage.text = gallery.name
				}
	}

	companion object {
		fun newInstance(gallery: Gallery): GalleryFragment {
			return GalleryFragment().apply {
				arguments = Bundle().apply {
					putParcelable(Gallery::class.java.simpleName, gallery)
				}
			}
		}
	}
}