CODEWITHSUNDEEP
androidandroid-fragmentskotlinandroid-recyclerview
SFAH
SFAH

Reputation: 644

Android: Problem using recycler view in fragment

I am using RecyclerView in Fragment ImagesliderFragment First it gives an expection of "recyclerview must not be null" so on stackover flow I got an answer that you should intialized your recyclerview by using following line 

  frag_rv = view.findViewById(R.id.frag_rv) as RecyclerView

But problem is that it gives me error on view. that only safe or non null asserted calls are allowed also my RecyclerView is not resolving can anyone explain me this what is the problem ?

code screenshot

ImagesliderFragment 

class ImagesliderFragment : Fragment() {

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    arguments?.let {
    }
}

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    inflater.inflate(R.layout.fragment_imageslider, container, false)
    frag_rv = view.findViewById(R.id.frag_rv) as RecyclerView
    frag_rv.layoutManager = LinearLayoutManager(context, LinearLayout.HORIZONTAL, false)
    return view
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

}

Upvotes: 0

Views: 73

Answers (4)

Jakir Hossain
Jakir Hossain

Reputation: 3930

Before you use view.findViewById you have to initialize it, also use val before frag_rv like the following.

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

  // here you have to initialize your view
  View view = inflater.inflate(R.layout.fragment_imageslider, container, false)
  val frag_rv = view.findViewById(R.id.frag_rv) as RecyclerView
  frag_rv.layoutManager = LinearLayoutManager(context, LinearLayout.HORIZONTAL, false)

  return view
}

Upvotes: 0

AskNilesh
AskNilesh

Reputation: 69671

Try this

class ImagesliderFragment : Fragment() {

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    arguments?.let {
    }
}

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {


    val myView = inflater.inflate(R.layout.fragment_imageslider, container, false)
    val frag_rv = myView.findViewById(R.id.frag_rv) as RecyclerView
    frag_rv.layoutManager = LinearLayoutManager(context, LinearLayout.HORIZONTAL, false)

    return myView
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

}

Also now no need to do findViewById()

SAMPLE CODE

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.LinearLayout
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.LinearLayoutManager
// import here your layout file like this
import kotlinx.android.synthetic.main.fragment_imageslider.view.*

class ImagesliderFragment : Fragment() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        arguments?.let {
        }
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {


        val myView = inflater.inflate(R.layout.fragment_imageslider, container, false)

        myView.frag_rv.layoutManager = LinearLayoutManager(context, LinearLayout.HORIZONTAL, false)

        return myView
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

    }

}

Upvotes: 2

SebastienRieu
SebastienRieu

Reputation: 1512

You should only use the onCreateView method to inflate the view and bind the iew in the onViewCreated method 

class ImagesliderFragment : Fragment() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

    }

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?) = inflater.inflate(R.layout.fragment_imageslider, container, false)!!

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

        val frag_rv = view.findViewById<RecyclerView>(R.id.frag_rv)            frag_rv.layoutManager = LinearLayoutManager(context, LinearLayout.HORIZONTAL, 
            false)
    }
}

Upvotes: 0

r2rek
r2rek

Reputation: 2233

You could change your onCreateView method to:

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
) = 
    inflater.inflate(R.layout.fragment_imageslider, container, false).apply {
    frag_rv = findViewById(R.id.frag_rv) as RecyclerView //val frag_rv if it's not declared elsewhere 
    frag_rv.layoutManager = LinearLayoutManager(context, LinearLayout.HORIZONTAL, false)
}

This way the view is inflated(via inflater.inflate) and you are using it to find the RecyclerView.

Upvotes: 0

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