For #1909: Tabs disappear intermittently (#2426)

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

@@ -166,6 +166,45 @@ class HomeFragment : Fragment(), CoroutineScope {
         homeDividerShadow.bringToFront()
     }
 
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        val state = sessionControlComponent.stateObservable.blockingFirst()
+        outState.putParcelableArrayList(
+            KEY_TABS,
+            ArrayList(state.tabs)
+        )
+        outState.putParcelableArrayList(
+            KEY_COLLECTIONS,
+            ArrayList(state.collections)
+        )
+        val modeInt = if (state.mode is Mode.Private) 0 else 1
+        outState.putInt(KEY_MODE, modeInt)
+    }
+
+    override fun onViewStateRestored(savedInstanceState: Bundle?) {
+        super.onViewStateRestored(savedInstanceState)
+        if (savedInstanceState != null) {
+            getManagedEmitter<SessionControlChange>().onNext(
+                SessionControlChange.TabsChange(
+                    (savedInstanceState.getParcelableArrayList<Tab>(
+                        KEY_TABS
+                    ) ?: arrayListOf()).toList()
+                )
+            )
+            getManagedEmitter<SessionControlChange>().onNext(
+                SessionControlChange.CollectionsChange(
+                    (savedInstanceState.getParcelableArrayList<TabCollection>(
+                        KEY_COLLECTIONS
+                    ) ?: arrayListOf()).toList()
+                )
+            )
+            val mode = if (savedInstanceState.getInt(KEY_MODE) == 0) Mode.Private else Mode.Normal
+            getManagedEmitter<SessionControlChange>().onNext(
+                SessionControlChange.ModeChange(mode)
+            )
+        }
+    }
+
     override fun onDestroyView() {
         homeMenu = null
         job.cancel()
@@ -469,6 +508,9 @@ class HomeFragment : Fragment(), CoroutineScope {
     }
 
     companion object {
-        const val toolbarPaddingDp = 12f
+        private const val toolbarPaddingDp = 12f
+        private const val KEY_TABS = "tabs"
+        private const val KEY_COLLECTIONS = "collections"
+        private const val KEY_MODE = "mode"
     }
 }

app/src/main/java/org/mozilla/fenix/home/sessioncontrol/SessionControlComponent.kt

@@ -5,6 +5,7 @@
 package org.mozilla.fenix.home.sessioncontrol
 
 import android.graphics.Bitmap
+import android.os.Parcelable
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.ViewModel
@@ -13,6 +14,7 @@ import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.RecyclerView
 import io.reactivex.Observable
 import io.reactivex.Observer
+import kotlinx.android.parcel.Parcelize
 import org.mozilla.fenix.mvi.Action
 import org.mozilla.fenix.mvi.ActionBusFactory
 import org.mozilla.fenix.mvi.Change
@@ -32,19 +34,25 @@ class SessionControlComponent(
         bus.getSafeManagedObservable(SessionControlChange::class.java)
     ) {
 
+    var stateObservable: Observable<SessionControlState>
+    lateinit var viewModel: SessionControlViewModel
+
     override fun initView() = SessionControlUIView(container, actionEmitter, changesObservable)
     val view: RecyclerView
         get() = uiView.view as RecyclerView
 
-    override fun render(): Observable<SessionControlState> =
+    override fun render(): Observable<SessionControlState> {
-        ViewModelProviders.of(owner, SessionControlViewModel.Factory(initialState, changesObservable))
+        viewModel = ViewModelProviders.of(owner, SessionControlViewModel.Factory(initialState, changesObservable))
-            .get(SessionControlViewModel::class.java).render(uiView)
+            .get(SessionControlViewModel::class.java)
+        return viewModel.render(uiView)
+    }
 
     init {
-        render()
+        stateObservable = render()
     }
 }
 
+@Parcelize
 data class Tab(
     val sessionId: String,
     val url: String,
@@ -52,15 +60,16 @@ data class Tab(
     val title: String,
     val selected: Boolean? = null,
     val thumbnail: Bitmap? = null
-)
+) : Parcelable
 
+@Parcelize
 data class TabCollection(
     val id: Int,
     val title: String,
     val tabs: MutableList<Tab>,
     val iconColor: Int = 0,
     var expanded: Boolean = false
-)
+) : Parcelable
 
 sealed class Mode {
     object Normal : Mode()