Using buttons in Bottom navigation crashes app

App Crashes when using button, link and .isGone function. It was working before but error occurred when switched to bottom navigation and fragments.

Could anyone explain what is happening.

Error:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.dmat.zerowaste, PID: 14673
    java.lang.NullPointerException
        at com.dmat.zerowaste.OrganicWasteFragment.onCreate(OrganicWasteFragment.kt:41)
        at androidx.fragment.app.Fragment.performCreate(Fragment.java:2949)
        at androidx.fragment.app.FragmentStateManager.create(FragmentStateManager.java:475)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:278)
        at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189)
        at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2100)
        at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
        at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:245)
        at android.app.ActivityThread.main(ActivityThread.java:8004)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:631)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:978)

File:

package com.dmat.zerowaste

import android.content.Intent
import android.os.Bundle
import android.text.method.LinkMovementMethod
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Button
import android.widget.TextView

import androidx.core.view.isGone
import androidx.fragment.app.Fragment
import kotlinx.android.synthetic.main.organic_waste_fragment_page.*

class OrganicWasteFragment : Fragment(R.layout.activity_recycle_page) {

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

    /*override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?): View? {
        val rootView = inflater.inflate(R.layout.organic_waste_fragment_page, container, false)
        return rootView
    }*/


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


        val compost_butt: Button = view?.findViewById(R.id.compost_butt)!!
        val animal_feed_butt: Button = view?.findViewById(R.id.animal_feed_butt)!!
        val animal_feed_content: View? = view?.findViewById(R.id.animal_feed_content)
        val rendering_butt: Button = view?.findViewById(R.id.rendering_butt)!!
        val rendering_content: View? = view?.findViewById(R.id.rendering_content)!!
        //val rapid_fermentation_butt: Button = view?.findViewById(R.id.fermentation_butt)!!
        val fermentation_link: TextView = view?.findViewById(R.id.fermentation_link)!!

        fermentation_link.setMovementMethod(LinkMovementMethod.getInstance())

        /*animal_feed_content.isGone = true
        rendering_content!!.isGone = true*/

        /*compost_butt.setOnClickListener {
            val compostIntent = Intent(context, composting_page::class.java)
            startActivity(compostIntent)

            animal_feed_butt.setCompoundDrawablesRelativeWithIntrinsicBounds(
                R.drawable.animal_feed_icon,
                0,
                R.drawable.plus,
                0
            )

            rendering_butt.setCompoundDrawablesRelativeWithIntrinsicBounds(
                R.drawable.rendering_icon,
                0,
                R.drawable.plus,
                0
            )

            animal_feed_content.isGone = true
            rendering_content.isGone = true

        }*/

        /*animal_feed_butt.setOnClickListener {
            animal_feed_butt.setCompoundDrawablesRelativeWithIntrinsicBounds(
                R.drawable.animal_feed_icon,
                0,
                R.drawable.minus_icon,
                0
            )

            animal_feed_content.isGone = false
            rendering_content.isGone = true

            rendering_butt.setCompoundDrawablesRelativeWithIntrinsicBounds(
                R.drawable.rendering_icon,
                0,
                R.drawable.plus,
                0
            )
        }

        rendering_butt.setOnClickListener {
            rendering_butt.setCompoundDrawablesRelativeWithIntrinsicBounds(
                R.drawable.rendering_icon,
                0,
                R.drawable.minus_icon,
                0
            )

            rendering_content.isGone = false
            animal_feed_content.isGone = true

            animal_feed_butt.setCompoundDrawablesRelativeWithIntrinsicBounds(
                R.drawable.animal_feed_icon,
                0,
                R.drawable.plus,
                0
            )
        }*/

    }
}

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