Move app initialization to onResume() to prevent blank screen (#1946)

* Move app initialization to onResume() to prevent app freeze when the app is launched from sleep state

* Convert Rx to coroutine

* Create ViewModel for StartupFragment

ground/src/main/java/com/google/android/ground/system/GoogleApiManager.kt

@@ -20,14 +20,13 @@ import com.google.android.gms.common.ConnectionResult
 import com.google.android.gms.common.GoogleApiAvailability
 import com.google.android.ground.rx.RxCompletable
 import dagger.hilt.android.qualifiers.ApplicationContext
-import dagger.hilt.android.scopes.ActivityScoped
-import io.reactivex.Completable
-import io.reactivex.CompletableEmitter
 import javax.inject.Inject
+import javax.inject.Singleton
+import kotlinx.coroutines.rx2.await
 
 private val INSTALL_API_REQUEST_CODE = GoogleApiAvailability::class.java.hashCode() and 0xffff
 
-@ActivityScoped
+@Singleton
 class GoogleApiManager
 @Inject
 constructor(
@@ -37,34 +36,36 @@ constructor(
 ) {
 
   /**
-   * Returns a stream that either completes immediately if Google Play Services are already
-   * installed, otherwise shows install dialog. Terminates with error if install not possible or
-   * cancelled.
+   * Displays a dialog to install Google Play Services, if missing. Throws an error if install not
+   * possible or cancelled.
    */
-  fun installGooglePlayServices(): Completable =
-    requestInstallOrComplete().ambWith(getNextInstallApiResult())
+  suspend fun installGooglePlayServices() {
+    val status = googleApiAvailability.isGooglePlayServicesAvailable(context)
+    if (status == ConnectionResult.SUCCESS) return
 
-  private fun requestInstallOrComplete(): Completable =
-    Completable.create { emitter: CompletableEmitter ->
-      val status = googleApiAvailability.isGooglePlayServicesAvailable(context)
-      if (status == ConnectionResult.SUCCESS) {
-        emitter.onComplete()
-      } else if (googleApiAvailability.isUserResolvableError(status)) {
-        activityStreams.withActivity {
-          googleApiAvailability.showErrorDialogFragment(it, status, INSTALL_API_REQUEST_CODE) {
-            emitter.onError(Exception("Google play services not available"))
-          }
-        }
-      } else {
-        emitter.onError(Exception("Google play services not available"))
-      }
-    }
+    val requestCode = INSTALL_API_REQUEST_CODE
+    startResolution(status, requestCode, GooglePlayServicesMissingException())
+    getNextResult(requestCode)
+  }
+
+  private fun startResolution(status: Int, requestCode: Int, throwable: Throwable) {
+    if (!googleApiAvailability.isUserResolvableError(status)) throw throwable
 
-  private fun getNextInstallApiResult(): Completable =
-    activityStreams.getNextActivityResult(INSTALL_API_REQUEST_CODE).flatMapCompletable {
-      RxCompletable.completeOrError(
-        { it.isOk() },
-        Exception::class.java // TODO: Throw appropriate Exception.
-      )
+    activityStreams.withActivity {
+      googleApiAvailability.showErrorDialogFragment(it, status, requestCode) { throw throwable }
     }
+  }
+
+  private suspend fun getNextResult(requestCode: Int) =
+    activityStreams
+      .getNextActivityResult(requestCode)
+      .flatMapCompletable {
+        RxCompletable.completeOrError(
+          { it.isOk() },
+          Exception::class.java // TODO: Throw appropriate Exception.
+        )
+      }
+      .await()
+
+  class GooglePlayServicesMissingException : Error("Google play services not available")
 }

ground/src/main/java/com/google/android/ground/ui/common/ViewModelModule.kt

@@ -39,6 +39,7 @@ import com.google.android.ground.ui.offlineareas.OfflineAreasViewModel
 import com.google.android.ground.ui.offlineareas.selector.OfflineAreaSelectorViewModel
 import com.google.android.ground.ui.offlineareas.viewer.OfflineAreaViewerViewModel
 import com.google.android.ground.ui.signin.SignInViewModel
+import com.google.android.ground.ui.startup.StartupViewModel
 import com.google.android.ground.ui.submissiondetails.SubmissionDetailsViewModel
 import com.google.android.ground.ui.surveyselector.SurveySelectorViewModel
 import com.google.android.ground.ui.syncstatus.SyncStatusViewModel
@@ -189,5 +190,10 @@ abstract class ViewModelModule {
   @ViewModelKey(CaptureLocationMapViewModel::class)
   abstract fun bindCaptureLocationMapViewModel(viewModel: CaptureLocationMapViewModel): ViewModel
 
+  @Binds
+  @IntoMap
+  @ViewModelKey(StartupViewModel::class)
+  abstract fun bindStartupViewModel(viewModel: StartupViewModel): ViewModel
+
   @Binds abstract fun bindViewModelFactory(factory: ViewModelFactory): ViewModelProvider.Factory
 }

ground/src/main/java/com/google/android/ground/ui/startup/StartupFragment.kt

@@ -15,49 +15,54 @@
  */
 package com.google.android.ground.ui.startup
 
-import android.content.Context
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.lifecycle.lifecycleScope
 import com.google.android.ground.R
-import com.google.android.ground.repository.UserRepository
-import com.google.android.ground.rx.RxAutoDispose
 import com.google.android.ground.system.GoogleApiManager
 import com.google.android.ground.ui.common.AbstractFragment
 import com.google.android.ground.ui.common.EphemeralPopups
 import dagger.hilt.android.AndroidEntryPoint
 import javax.inject.Inject
+import kotlinx.coroutines.launch
 import timber.log.Timber
 
 @AndroidEntryPoint(AbstractFragment::class)
 class StartupFragment : Hilt_StartupFragment() {
 
-  @Inject lateinit var googleApiManager: GoogleApiManager
   @Inject lateinit var popups: EphemeralPopups
-  @Inject lateinit var userRepository: UserRepository
+
+  private lateinit var viewModel: StartupViewModel
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    viewModel = getViewModel(StartupViewModel::class.java)
+  }
 
   override fun onCreateView(
     inflater: LayoutInflater,
     container: ViewGroup?,
     savedInstanceState: Bundle?
   ): View? = inflater.inflate(R.layout.startup_frag, container, false)
 
-  override fun onAttach(context: Context) {
-    super.onAttach(context)
-    googleApiManager
-      .installGooglePlayServices()
-      .`as`(RxAutoDispose.autoDisposable<Any>(requireActivity()))
-      .subscribe({ onGooglePlayServicesReady() }) { t: Throwable -> onGooglePlayServicesFailed(t) }
-  }
-
-  private fun onGooglePlayServicesReady() {
-    userRepository.init()
+  override fun onResume() {
+    super.onResume()
+    viewLifecycleOwner.lifecycleScope.launch {
+      try {
+        viewModel.initializeLogin()
+      } catch (t: Throwable) {
+        onInitFailed(t)
+      }
+    }
   }
 
-  private fun onGooglePlayServicesFailed(t: Throwable) {
-    Timber.e(t, "Google Play Services install failed")
-    popups.showError(R.string.google_api_install_failed)
+  private fun onInitFailed(t: Throwable) {
+    Timber.e(t, "Failed to launch app")
+    if (t is GoogleApiManager.GooglePlayServicesMissingException) {
+      popups.showError(R.string.google_api_install_failed)
+    }
     requireActivity().finish()
   }
 }

ground/src/main/java/com/google/android/ground/ui/startup/StartupViewModel.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * 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
+ *
+ *     https://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.google.android.ground.ui.startup
+
+import com.google.android.ground.repository.UserRepository
+import com.google.android.ground.system.GoogleApiManager
+import com.google.android.ground.ui.common.AbstractViewModel
+import javax.inject.Inject
+
+class StartupViewModel
+@Inject
+internal constructor(
+  private val googleApiManager: GoogleApiManager,
+  private val userRepository: UserRepository
+) : AbstractViewModel() {
+
+  /** Checks & installs Google Play Services and initializes the login flow. */
+  suspend fun initializeLogin() {
+    googleApiManager.installGooglePlayServices()
+    userRepository.init()
+  }
+}