Add loading state in the MediaOutputViewModel

We need to distinguish between loading and null session in the
MediaOutputViewModel to wait for the initial load to finish.

Flag: aconfig new_volume_panel TRUNKFOOD
Test: manual on the phone
Fixes: 332721662
Change-Id: Ib9eb6cdade98fdd75ccacbac7b49caa782ba8bd6

2 files changed, 51 insertions, 10 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/volume/panel/component/mediaoutput/ui/viewmodel/MediaOutputViewModel.kt b/packages/SystemUI/src/com/android/systemui/volume/panel/component/mediaoutput/ui/viewmodel/MediaOutputViewModel.kt
index 6b237f8e329b..f19fa20bd999 100644
--- a/packages/SystemUI/src/com/android/systemui/volume/panel/component/mediaoutput/ui/viewmodel/MediaOutputViewModel.kt
+++ b/packages/SystemUI/src/com/android/systemui/volume/panel/component/mediaoutput/ui/viewmodel/MediaOutputViewModel.kt
@@ -27,6 +27,7 @@ import com.android.systemui.volume.panel.component.mediaoutput.domain.interactor
 import com.android.systemui.volume.panel.component.mediaoutput.domain.interactor.MediaOutputInteractor
 import com.android.systemui.volume.panel.component.mediaoutput.shared.model.SessionWithPlayback
 import com.android.systemui.volume.panel.dagger.scope.VolumePanelScope
+import com.android.systemui.volume.panel.shared.model.Result
 import com.android.systemui.volume.panel.ui.VolumePanelUiEvent
 import javax.inject.Inject
 import kotlinx.coroutines.CoroutineScope
@@ -34,6 +35,7 @@ import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.map
@@ -53,32 +55,40 @@ constructor(
     private val uiEventLogger: UiEventLogger,
 ) {
 
-    private val sessionWithPlayback: StateFlow<SessionWithPlayback?> =
+    private val sessionWithPlayback: StateFlow<Result<SessionWithPlayback?>> =
         interactor.defaultActiveMediaSession
             .flatMapLatest { session ->
                 if (session == null) {
-                    flowOf(null)
+                    flowOf(Result.Data<SessionWithPlayback?>(null))
                 } else {
-                    mediaDeviceSessionInteractor.playbackState(session).map { playback ->
-                        playback?.let { SessionWithPlayback(session, it) }
-                    }
+                    mediaDeviceSessionInteractor
+                        .playbackState(session)
+                        .map { playback ->
+                            playback?.let {
+                                Result.Data<SessionWithPlayback?>(SessionWithPlayback(session, it))
+                            }
+                        }
+                        .filterNotNull()
                 }
             }
             .stateIn(
                 coroutineScope,
                 SharingStarted.Eagerly,
-                null,
+                Result.Loading(),
             )
 
     val connectedDeviceViewModel: StateFlow<ConnectedDeviceViewModel?> =
         combine(sessionWithPlayback, interactor.currentConnectedDevice) {
                 mediaDeviceSession,
                 currentConnectedDevice ->
+                if (mediaDeviceSession !is Result.Data) {
+                    return@combine null
+                }
                 ConnectedDeviceViewModel(
-                    if (mediaDeviceSession?.playback?.isActive == true) {
+                    if (mediaDeviceSession.data?.playback?.isActive == true) {
                         context.getString(
                             R.string.media_output_label_title,
-                            mediaDeviceSession.session.appLabel
+                            mediaDeviceSession.data.session.appLabel
                         )
                     } else {
                         context.getString(R.string.media_output_title_without_playing)
@@ -96,7 +106,10 @@ constructor(
         combine(sessionWithPlayback, interactor.currentConnectedDevice) {
                 mediaDeviceSession,
                 currentConnectedDevice ->
-                if (mediaDeviceSession?.playback?.isActive == true) {
+                if (mediaDeviceSession !is Result.Data) {
+                    return@combine null
+                }
+                if (mediaDeviceSession.data?.playback?.isActive == true) {
                     val icon =
                         currentConnectedDevice?.icon?.let { Icon.Loaded(it, null) }
                             ?: Icon.Resource(
@@ -130,6 +143,7 @@ constructor(
 
     fun onBarClick(expandable: Expandable) {
         uiEventLogger.log(VolumePanelUiEvent.VOLUME_PANEL_MEDIA_OUTPUT_CLICKED)
-        actionsInteractor.onBarClick(sessionWithPlayback.value, expandable)
+        val result = sessionWithPlayback.value
+        actionsInteractor.onBarClick((result as? Result.Data)?.data, expandable)
     }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/volume/panel/shared/model/Result.kt b/packages/SystemUI/src/com/android/systemui/volume/panel/shared/model/Result.kt
new file mode 100644
index 000000000000..8793538aac0d
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/volume/panel/shared/model/Result.kt
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.volume.panel.shared.model
+
+/** Models a loadable result */
+sealed interface Result<T> {
+
+    /** The data is still loading */
+    class Loading<T> : Result<T>
+
+    /** The data is loaded successfully */
+    data class Data<T>(val data: T) : Result<T>
+}