ViewPager2 | View.ClickListener not called

Question

I use new android widget ViewPager2 version 1.0.0-alpha03 and when I set click listener on it method onClick() not called.

My Actvity class:

class MainActivity : AppCompatActivity() {

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

        supportFragmentManager.beginTransaction()
            .add(R.id.fragmentContent, SecondFragment.newInstance(), SecondFragment.TAG)
            .addToBackStack(SecondFragment.TAG)
            .commit()
    }
}

My Fragment:

class SecondFragment : Fragment() {

    companion object {
        val TAG = SecondFragment::class.java.canonicalName

        fun newInstance(): SecondFragment = SecondFragment()
    }

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

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        viewPager2.setOnClickListener {
            Log.d("logi", "click : ")
        }
    }
}

My layout xml file:

<androidx.coordinatorlayout.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewPager2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

Any assumption or workaround?

Answer 1

I found a solution! ViewPager2 contains RecyclerView and we must work with it as RecyclerView. I created RecyclerView.Adapter and set the ClickListener on itemView into the constructor RecyclerView.ViewHolder and VOILA!!!

in Fragment:

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        viewPager2.adapter = ViewPager2Adapter {
            Log.d("logi", "clicked at : $it")
        }
    }

RecyclerView adapter:

class ViewPager2Adapter(private val itemClickListener: (Int) -> (Unit)) :
    RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    val items = mutableListOf<Any>()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder =
        ItemViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.item, parent, false))

    override fun getItemCount(): Int = items.size 

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        // bind your items
    }

    private inner class ItemViewHolder(itemView: View): RecyclerView.ViewHolder(itemView) {

        init {
            itemView.setOnClickListener {
                Log.d("logi", "Click!") // WORKS!!!
                itemClickListener(adapterPosition)
            }
        }
    }
}

Answer 2

Another approach can be like below:

class MyAdapter(
    private val items: List<Any>,
    private val onItemClickListener: OnItemClickListener
) : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val itemView = parent.inflate(R.layout.item_details_view_pager)
        return MyViewHolder(itemView)
    }

    override fun getItemCount(): Int = items.size

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.imageView.apply {
            setOnClickListener {
                onItemClickListener.onItemClick(position)
            }
            ...
        }
    }

    inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val imageView: ImageView = itemView.findViewById(R.id.some_image_view)
    }
}

The constructor parameter onItemClickListener could be a lambda as well, but it's a simple interface for me:

interface OnItemClickListener {
    fun onItemClick(position: Int)
}