Closes #17443: IllegalStateException in startPostponedEnterTransition on HomeFragment

app/src/main/java/org/mozilla/fenix/browser/BrowserFragment.kt

@@ -5,9 +5,7 @@
 package org.mozilla.fenix.browser
 
 import android.content.Context
-import android.os.Bundle
 import android.os.StrictMode
-import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.appcompat.content.res.AppCompatResources
@@ -54,17 +52,6 @@ class BrowserFragment : BaseBrowserFragment(), UserInteractionHandler {
     private var openInAppOnboardingObserver: OpenInAppOnboardingObserver? = null
     private var pwaOnboardingObserver: PwaOnboardingObserver? = null
 
-    override fun onCreateView(
-        inflater: LayoutInflater,
-        container: ViewGroup?,
-        savedInstanceState: Bundle?
-    ): View {
-        val view = super.onCreateView(inflater, container, savedInstanceState)
-
-        startPostponedEnterTransition()
-        return view
-    }
-
     @Suppress("LongMethod")
     override fun initializeUI(view: View): Session? {
         val context = requireContext()

app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt

@@ -113,7 +113,6 @@ import org.mozilla.fenix.settings.SupportUtils
 import org.mozilla.fenix.settings.SupportUtils.SumoTopic.HELP
 import org.mozilla.fenix.settings.deletebrowsingdata.deleteAndQuit
 import org.mozilla.fenix.theme.ThemeManager
-import org.mozilla.fenix.utils.FragmentPreDrawManager
 import org.mozilla.fenix.utils.ToolbarPopupWindow
 import org.mozilla.fenix.utils.allowUndo
 import org.mozilla.fenix.whatsnew.WhatsNew
@@ -170,7 +169,6 @@ class HomeFragment : Fragment() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
-        postponeEnterTransition()
         bundleArgs = args.toBundle()
         lifecycleScope.launch(IO) {
             if (!onboarding.userHasBeenOnboarded()) {
@@ -339,19 +337,7 @@ class HomeFragment : Fragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
 
-        FragmentPreDrawManager(this).execute {
-            homeViewModel.layoutManagerState?.also { parcelable ->
-                sessionControlView!!.view.layoutManager?.onRestoreInstanceState(parcelable)
-            }
-            homeViewModel.layoutManagerState = null
-
-            // We have to delay so that the keyboard collapses and the view is resized before the
-            // animation from SearchFragment happens
-            delay(ANIMATION_DELAY)
-        }
-
         observeSearchEngineChanges()
-
         createHomeMenu(requireContext(), WeakReference(view.menuButton))
         createTabCounterMenu(view)
 
@@ -654,12 +640,6 @@ class HomeFragment : Fragment() {
         }.show()
     }
 
-    override fun onStop() {
-        super.onStop()
-        homeViewModel.layoutManagerState =
-            sessionControlView!!.view.layoutManager?.onSaveInstanceState()
-    }
-
     override fun onResume() {
         super.onResume()
         if (browsingModeManager.mode == BrowsingMode.Private) {

app/src/main/java/org/mozilla/fenix/home/HomeScreenViewModel.kt

@@ -4,7 +4,6 @@
 
 package org.mozilla.fenix.home
 
-import android.os.Parcelable
 import androidx.lifecycle.ViewModel
 
 class HomeScreenViewModel : ViewModel() {
@@ -13,8 +12,6 @@ class HomeScreenViewModel : ViewModel() {
      */
     var sessionToDelete: String? = null
 
-    var layoutManagerState: Parcelable? = null
-
     /**
      * Used to remember if we need to scroll to top of the homeFragment's recycleView (top sites) see #8561
      * */

app/src/main/java/org/mozilla/fenix/utils/FragmentPreDrawManager.kt

@@ -1,30 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-package org.mozilla.fenix.utils
-
-import androidx.core.view.doOnPreDraw
-import androidx.fragment.app.Fragment
-import androidx.lifecycle.lifecycleScope
-import kotlinx.coroutines.launch
-
-/**
- * Helper class that allows executing code immediately before [Fragment]s View being drawn.
- */
-class FragmentPreDrawManager(
-    private val fragment: Fragment
-) {
-    init {
-        fragment.postponeEnterTransition()
-    }
-
-    fun execute(code: suspend () -> Unit) {
-        fragment.view?.doOnPreDraw {
-            fragment.viewLifecycleOwner.lifecycleScope.launch {
-                code()
-                fragment.startPostponedEnterTransition()
-            }
-        }
-    }
-}

app/src/test/java/org/mozilla/fenix/utils/FragmentPreDrawManagerTest.kt

@@ -1,33 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-package org.mozilla.fenix.utils
-
-import androidx.core.view.OneShotPreDrawListener
-import androidx.fragment.app.Fragment
-import io.mockk.mockk
-import io.mockk.verify
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.ObsoleteCoroutinesApi
-import kotlinx.coroutines.test.runBlockingTest
-import org.junit.Test
-
-@ObsoleteCoroutinesApi
-@ExperimentalCoroutinesApi
-class FragmentPreDrawManagerTest {
-    private fun doNothing() { /*noop*/ }
-
-    @Test
-    fun `execute doOnPreDraw`() {
-        runBlockingTest {
-            val fragmentMock = mockk<Fragment>(relaxed = true)
-            val fragmentPreDrawManager = FragmentPreDrawManager(fragmentMock)
-            val listener = OneShotPreDrawListener.add(fragmentMock.view!!) { mockk() }
-
-            verify { fragmentMock.postponeEnterTransition() }
-            fragmentPreDrawManager.execute { doNothing() }
-            verify { fragmentMock.view?.viewTreeObserver?.addOnPreDrawListener(listener) }
-        }
-    }
-}