I want to make changes in my Layout that contains ViewPager2 according to the position of ViewPager2. Example -> I want to make a Button Visible when the ViewPager2 has the last item or position. But I am Not able to do so, Any Help and Suggestions would be Very Helpful Thank You.

My Adapter :

open class ImagesliderAdapter(private val context: Context, private val list: ArrayList<HomePageSlideEntity>, private val viewPager2: ViewPager2): RecyclerView.Adapter<RecyclerView.ViewHolder>() {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        return MyViewHolder(LayoutInflater.from(context).inflate(R.layout.item_imageslider, parent, false))
    }


    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        val model = list[position]
        if(position==list.size-1) {
            viewPager2.post(runnable)
        }
        if(holder is MyViewHolder) {
            holder.itemView.findViewById<ImageView>(R.id.ivimageslider).setImageURI(Uri.parse(model.image))
        }
    }

    override fun getItemCount(): Int {
        return list.size
    }

    private val runnable = Runnable {
        list.addAll(list)
        notifyDataSetChanged()
    }

    private class MyViewHolder(view: View): RecyclerView.ViewHolder(view)
}

CodePudding user response：

Use registerOnPageChangeCallback in your ViewPager2.

     binding.viewPager2.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {

                override fun onPageScrolled(
                    position: Int,
                    positionOffset: Float,
                    positionOffsetPixels: Int
                ) {
                    super.onPageScrolled(position, positionOffset, positionOffsetPixels)
                    Log.d("Page", "onPageScrolled: $position")
                }

                override fun onPageSelected(position: Int) {
                    super.onPageSelected(position)

                    Log.d("Page", "onPageSelected: $position")

                    // use position and do what ever you want
                    //for 1st page
                    if (position <= 0) {
                        btn.visibility = View.GONE
                    } else {
                        btn.visibility = View.VISIBLE
                    }
                    //for last page
                    if (position   1 >= args.content.items.size) {
                        btn.visibility = View.GONE
                    } else {
                        btn.visibility = View.VISIBLE
                    }


                }

                override fun onPageScrollStateChanged(state: Int) {
                    super.onPageScrollStateChanged(state)
                }

            })

CodePudding user response：

You are using RecyclerView.ViewHolder instead of MyViewHolder in your adapter. Replace RecyclerView.ViewHolder with MyViewHolder and it should work properly then.