viewBinding delegate

CustomFragment.kt

import android.os.Bundle
import android.view.View

class CustomFragment : Fragment(R.layout.fragment_round_up_accounts) {
  
    private val binding by viewBinding(FragmentCustomBinding::bind)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        
        // Use binding here
    }
    
}

FragmentViewBindingDelegate.kt

import android.os.Handler
import android.os.Looper
import android.view.View
import androidx.fragment.app.Fragment
import androidx.lifecycle.DefaultLifecycleObserver
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleOwner
import androidx.viewbinding.ViewBinding
import kotlin.properties.ReadOnlyProperty
import kotlin.reflect.KProperty

private class FragmentViewBindingDelegate<T : ViewBinding>(
    val fragment: Fragment,
    val factory: (View) -> T
) : ReadOnlyProperty<Fragment, T>, DefaultLifecycleObserver {
    private var binding: T? = null
    private var waitingToDestroyBinding = false

    override fun getValue(thisRef: Fragment, property: KProperty<*>): T {
        alertIfNotOnMainThread()
        if (waitingToDestroyBinding &&
            fragment.viewLifecycleOwner.lifecycle.currentState != Lifecycle.State.DESTROYED
        ) {
            // Don't force clear binding if we're in the DESTROYED state
            // so that binding can still be reused within Fragment.onDestroyView
            binding = null
            waitingToDestroyBinding = false
        }
        return binding ?: fragment.viewLifecycleOwner.lifecycle.run {
            if (!currentState.isAtLeast(Lifecycle.State.INITIALIZED)) {
                error("Called before onCreateView or after onDestroyView.")
            }

            factory(thisRef.requireView()).also {
                addObserver(this@FragmentViewBindingDelegate)
                binding = it
            }
        }
    }

    override fun onDestroy(owner: LifecycleOwner) {
        // Fragment.viewLifecycleOwner calls FullLifecycleObserver.onDestroy before
        // Fragment.onDestroyView, so postpone clearing the value
        alertIfNotOnMainThread()
        waitingToDestroyBinding = true
        Handler(Looper.getMainLooper()).post {
            if (waitingToDestroyBinding) {
                binding = null
                waitingToDestroyBinding = false
            }
        }
    }

    private fun alertIfNotOnMainThread() {
        if (BuildConfig.DEBUG) {
            require(Looper.getMainLooper().isCurrentThread) { "Why aren't you on the main thread?" }
        }
    }
}

fun <T : ViewBinding> Fragment.viewBinding(factory: (View) -> T): ReadOnlyProperty<Fragment, T> =
    FragmentViewBindingDelegate(this, factory)