Persist GooglePayLauncherViewModel state

CHANGELOG.md

@@ -3,7 +3,10 @@
 ## X.X.X
 
 ### PaymentSheet
-* [Fixed][5215](https://github.com/stripe/stripe-android/pull/5215) Fix issue with us_bank_account appearing in payment sheet when Financial Connections SDK is not available
+* [Fixed] [5215](https://github.com/stripe/stripe-android/pull/5215) Fix issue with us_bank_account appearing in payment sheet when Financial Connections SDK is not available
+
+### Payments
+* [FIXED] [5226](https://github.com/stripe/stripe-android/pull/5226) Persist `GooglePayLauncherViewModel` state across process death
 
 ## 20.6.2 - 2022-06-23
 This release contains several bug fixes for Payments, reduces the size of StripeCardScan, and adds new `rememberFinancialConnections` features for Financial Connections.

example/src/main/java/com/stripe/example/activity/GooglePayLauncherIntegrationActivity.kt

@@ -28,20 +28,24 @@ class GooglePayLauncherIntegrationActivity : StripeIntentActivity() {
         super.onCreate(savedInstanceState)
         setContentView(viewBinding.root)
 
-        viewBinding.progressBar.isVisible = true
-        viewBinding.googlePayButton.isEnabled = false
-
-        viewModel.createPaymentIntent(COUNTRY_CODE)
-            .observe(this) { result ->
-                result.fold(
-                    onSuccess = ::onPaymentIntentCreated,
-                    onFailure = { error ->
-                        snackbarController.show(
-                            "Could not create PaymentIntent. ${error.message}"
-                        )
-                    }
-                )
-            }
+        // If the activity is being recreated, load the client secret if it has already been fetched
+        savedInstanceState?.let {
+            clientSecret = it.getString(SAVED_CLIENT_SECRET, "")
+        }
+
+        if (clientSecret.isBlank()) {
+            viewModel.createPaymentIntent(COUNTRY_CODE)
+                .observe(this) { result ->
+                    result.fold(
+                        onSuccess = ::onPaymentIntentCreated,
+                        onFailure = { error ->
+                            snackbarController.show(
+                                "Could not create PaymentIntent. ${error.message}"
+                            )
+                        }
+                    )
+                }
+        }
 
         val googlePayLauncher = GooglePayLauncher(
             activity = this,
@@ -52,9 +56,9 @@ class GooglePayLauncherIntegrationActivity : StripeIntentActivity() {
                 billingAddressConfig = GooglePayLauncher.BillingAddressConfig(
                     isRequired = true,
                     format = GooglePayLauncher.BillingAddressConfig.Format.Full,
-                    isPhoneNumberRequired = true
+                    isPhoneNumberRequired = false
                 ),
-                existingPaymentMethodRequired = true
+                existingPaymentMethodRequired = false
             ),
             readyCallback = ::onGooglePayReady,
             resultCallback = ::onGooglePayResult
@@ -64,6 +68,13 @@ class GooglePayLauncherIntegrationActivity : StripeIntentActivity() {
             viewBinding.progressBar.isVisible = true
             googlePayLauncher.presentForPaymentIntent(clientSecret)
         }
+
+        updateUi()
+    }
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        outState.putString(SAVED_CLIENT_SECRET, clientSecret)
     }
 
     private fun updateUi() {
@@ -98,10 +109,12 @@ class GooglePayLauncherIntegrationActivity : StripeIntentActivity() {
             }
         }.let {
             snackbarController.show(it)
+            googlePayButton.isEnabled = false
         }
     }
 
     private companion object {
         private const val COUNTRY_CODE = "US"
+        private const val SAVED_CLIENT_SECRET = "client_secret"
     }
 }

payments-core/src/main/java/com/stripe/android/googlepaylauncher/GooglePayLauncherActivity.kt

@@ -35,7 +35,8 @@ internal class GooglePayLauncherActivity : AppCompatActivity() {
     private val viewModel: GooglePayLauncherViewModel by viewModels {
         GooglePayLauncherViewModel.Factory(
             application,
-            args
+            args,
+            this
         )
     }
 
@@ -68,14 +69,13 @@ internal class GooglePayLauncherActivity : AppCompatActivity() {
         }
 
         if (!viewModel.hasLaunched) {
-            viewModel.hasLaunched = true
-
             lifecycleScope.launch {
                 runCatching {
                     viewModel.createLoadPaymentDataTask()
                 }.fold(
                     onSuccess = {
                         payWithGoogle(it)
+                        viewModel.hasLaunched = true
                     },
                     onFailure = {
                         viewModel.updateResult(

payments-core/src/main/java/com/stripe/android/googlepaylauncher/GooglePayLauncherViewModel.kt

@@ -2,12 +2,15 @@ package com.stripe.android.googlepaylauncher
 
 import android.app.Application
 import android.content.Intent
+import android.os.Bundle
 import androidx.annotation.VisibleForTesting
+import androidx.lifecycle.AbstractSavedStateViewModelFactory
 import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
-import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.distinctUntilChanged
 import androidx.lifecycle.viewModelScope
+import androidx.savedstate.SavedStateRegistryOwner
 import com.google.android.gms.tasks.Task
 import com.google.android.gms.wallet.PaymentData
 import com.google.android.gms.wallet.PaymentDataRequest
@@ -35,16 +38,25 @@ import kotlinx.coroutines.launch
 import org.json.JSONObject
 import kotlin.coroutines.CoroutineContext
 
+@Suppress("LongParameterList")
 internal class GooglePayLauncherViewModel(
     private val paymentsClient: PaymentsClient,
     private val requestOptions: ApiRequest.Options,
     private val args: GooglePayLauncherContract.Args,
     private val stripeRepository: StripeRepository,
     private val paymentController: PaymentController,
     private val googlePayJsonFactory: GooglePayJsonFactory,
-    private val googlePayRepository: GooglePayRepository
+    private val googlePayRepository: GooglePayRepository,
+    private val savedStateHandle: SavedStateHandle
 ) : ViewModel() {
-    var hasLaunched: Boolean = false
+    /**
+     * [hasLaunched] indicates whether Google Pay has already been launched, and must be persisted
+     * across process death in case the Activity and ViewModel are destroyed while the user is
+     * interacting with Google Pay.
+     */
+    var hasLaunched: Boolean
+        get() = savedStateHandle.get<Boolean>(HAS_LAUNCHED_KEY) == true
+        set(value) = savedStateHandle.set(HAS_LAUNCHED_KEY, value)
 
     private val _googleResult = MutableLiveData<GooglePayLauncher.Result>()
     internal val googlePayResult = _googleResult.distinctUntilChanged()
@@ -209,11 +221,17 @@ internal class GooglePayLauncherViewModel(
     internal class Factory(
         private val application: Application,
         private val args: GooglePayLauncherContract.Args,
+        owner: SavedStateRegistryOwner,
         private val enableLogging: Boolean = false,
-        private val workContext: CoroutineContext = Dispatchers.IO
-    ) : ViewModelProvider.Factory {
+        private val workContext: CoroutineContext = Dispatchers.IO,
+        defaultArgs: Bundle? = null
+    ) : AbstractSavedStateViewModelFactory(owner, defaultArgs) {
         @Suppress("UNCHECKED_CAST")
-        override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        override fun <T : ViewModel> create(
+            key: String,
+            modelClass: Class<T>,
+            handle: SavedStateHandle
+        ): T {
             val googlePayEnvironment = args.config.environment
             val logger = Logger.getInstance(enableLogging)
 
@@ -265,8 +283,14 @@ internal class GooglePayLauncherViewModel(
                     googlePayConfig = GooglePayConfig(publishableKey, stripeAccountId),
                     isJcbEnabled = args.config.isJcbEnabled
                 ),
-                googlePayRepository
+                googlePayRepository,
+                handle
             ) as T
         }
     }
+
+    companion object {
+        @VisibleForTesting
+        const val HAS_LAUNCHED_KEY = "has_launched"
+    }
 }

payments-core/src/test/java/com/stripe/android/googlepaylauncher/GooglePayLauncherViewModelTest.kt

@@ -1,6 +1,7 @@
 package com.stripe.android.googlepaylauncher
 
 import android.content.Intent
+import androidx.lifecycle.SavedStateHandle
 import com.google.android.gms.tasks.Task
 import com.google.android.gms.wallet.PaymentData
 import com.google.android.gms.wallet.PaymentsClient
@@ -14,6 +15,7 @@ import com.stripe.android.SetupIntentResult
 import com.stripe.android.StripePaymentController
 import com.stripe.android.core.exception.StripeException
 import com.stripe.android.core.networking.ApiRequest
+import com.stripe.android.googlepaylauncher.GooglePayLauncherViewModel.Companion.HAS_LAUNCHED_KEY
 import com.stripe.android.model.ConfirmPaymentIntentParams
 import com.stripe.android.model.ConfirmSetupIntentParams
 import com.stripe.android.model.ConfirmStripeIntentParams
@@ -42,6 +44,7 @@ import kotlin.test.assertFailsWith
 @RunWith(RobolectricTestRunner::class)
 class GooglePayLauncherViewModelTest {
     private val stripeRepository = FakeStripeRepository()
+    private val savedStateHandle = SavedStateHandle()
     private val googlePayJsonFactory = GooglePayJsonFactory(
         googlePayConfig = GooglePayConfig(
             ApiKeyFixtures.FAKE_PUBLISHABLE_KEY,
@@ -124,6 +127,17 @@ class GooglePayLauncherViewModelTest {
             )
     }
 
+    @Test
+    fun `hasLaunched is stored in savedStateHandle`() {
+        val viewModel = createViewModel()
+
+        assertThat(viewModel.hasLaunched).isFalse()
+
+        viewModel.hasLaunched = true
+
+        assertThat(savedStateHandle.get<Boolean>(HAS_LAUNCHED_KEY)).isTrue()
+    }
+
     @Test
     fun `getResultFromConfirmation() using PaymentIntent should return expected result`() =
         runTest {
@@ -218,7 +232,8 @@ class GooglePayLauncherViewModelTest {
         stripeRepository,
         paymentController,
         googlePayJsonFactory,
-        googlePayRepository
+        googlePayRepository,
+        savedStateHandle
     )
 
     private class FakePaymentController : AbsPaymentController() {