Fix don't keep activities on add fragment.

paymentsheet/src/main/java/com/stripe/android/paymentsheet/BaseAddPaymentMethodFragment.kt

@@ -15,12 +15,11 @@ import androidx.fragment.app.commit
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.lifecycleScope
 import androidx.recyclerview.widget.LinearLayoutManager
-import com.stripe.android.model.StripeIntent
 import com.stripe.android.core.injection.InjectorKey
+import com.stripe.android.model.StripeIntent
 import com.stripe.android.paymentsheet.analytics.EventReporter
 import com.stripe.android.paymentsheet.databinding.FragmentPaymentsheetAddPaymentMethodBinding
 import com.stripe.android.paymentsheet.forms.FormFieldValues
-import com.stripe.android.ui.core.Amount
 import com.stripe.android.paymentsheet.model.PaymentSelection
 import com.stripe.android.paymentsheet.model.SupportedPaymentMethod
 import com.stripe.android.paymentsheet.paymentdatacollection.CardDataCollectionFragment
@@ -30,6 +29,7 @@ import com.stripe.android.paymentsheet.paymentdatacollection.TransformToPaymentM
 import com.stripe.android.paymentsheet.ui.AddPaymentMethodsFragmentFactory
 import com.stripe.android.paymentsheet.ui.AnimationConstants
 import com.stripe.android.paymentsheet.viewmodels.BaseSheetViewModel
+import com.stripe.android.ui.core.Amount
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
@@ -93,32 +93,48 @@ internal abstract class BaseAddPaymentMethodFragment(
         }
 
         if (paymentMethods.isNotEmpty()) {
-            replacePaymentMethodFragment(paymentMethods[selectedPaymentMethodIndex])
+            // If the activity is destroyed and recreated, then the fragment is already present
+            // and doesn't need to be replaced, only the selected payment method needs to be set
+            if (savedInstanceState == null) {
+                replacePaymentMethodFragment(paymentMethods[selectedPaymentMethodIndex])
+            } else {
+                selectedPaymentMethod = paymentMethods[selectedPaymentMethodIndex]
+            }
         }
 
         sheetViewModel.processing.observe(viewLifecycleOwner) { isProcessing ->
             (getFragment() as? ComposeFormDataCollectionFragment)?.setProcessing(isProcessing)
         }
 
+        // If the activity was destroyed and recreated then we need to re-attach the fragment,
+        // as attach will not be called again.
+        childFragmentManager.fragments.forEach { fragment ->
+            attachComposeFragmentViewModel(fragment)
+        }
+
         childFragmentManager.addFragmentOnAttachListener { _, fragment ->
-            (fragment as? ComposeFormDataCollectionFragment)?.let { formFragment ->
-                // Need to access the formViewModel so it is constructed.
-                val formViewModel = formFragment.formViewModel
-                viewLifecycleOwner.lifecycleScope.launch {
-                    formViewModel.completeFormValues.collect { formFieldValues ->
-                        sheetViewModel.updateSelection(
-                            transformToPaymentSelection(
-                                formFieldValues,
-                                formFragment.paramKeySpec,
-                                selectedPaymentMethod
-                            )
+            attachComposeFragmentViewModel(fragment)
+        }
+
+        eventReporter.onShowNewPaymentOptionForm()
+    }
+
+    private fun attachComposeFragmentViewModel(fragment: Fragment) {
+        (fragment as? ComposeFormDataCollectionFragment)?.let { formFragment ->
+            // Need to access the formViewModel so it is constructed.
+            val formViewModel = formFragment.formViewModel
+            viewLifecycleOwner.lifecycleScope.launch {
+                formViewModel.completeFormValues.collect { formFieldValues ->
+                    sheetViewModel.updateSelection(
+                        transformToPaymentSelection(
+                            formFieldValues,
+                            formFragment.paramKeySpec,
+                            selectedPaymentMethod
                         )
-                    }
+                    )
                 }
             }
         }
-
-        eventReporter.onShowNewPaymentOptionForm()
     }
 
     private fun setupRecyclerView(

paymentsheet/src/main/java/com/stripe/android/paymentsheet/PaymentSheetActivity.kt

@@ -18,14 +18,16 @@ import androidx.lifecycle.lifecycleScope
 import com.google.android.material.appbar.AppBarLayout
 import com.google.android.material.appbar.MaterialToolbar
 import com.stripe.android.googlepaylauncher.GooglePayPaymentMethodLauncherContract
+import com.stripe.android.model.PaymentIntent
+import com.stripe.android.model.SetupIntent
 import com.stripe.android.paymentsheet.PaymentSheetViewModel.CheckoutIdentifier
 import com.stripe.android.paymentsheet.databinding.ActivityPaymentSheetBinding
-import com.stripe.android.ui.core.Amount
 import com.stripe.android.paymentsheet.model.PaymentSelection
 import com.stripe.android.paymentsheet.model.PaymentSheetViewState
 import com.stripe.android.paymentsheet.ui.AnimationConstants
 import com.stripe.android.paymentsheet.ui.BaseSheetActivity
 import com.stripe.android.paymentsheet.viewmodels.BaseSheetViewModel
+import com.stripe.android.ui.core.Amount
 import com.stripe.android.ui.core.CurrencyFormatter
 import kotlinx.coroutines.launch
 import java.security.InvalidParameterException
@@ -106,7 +108,22 @@ internal class PaymentSheetActivity : BaseSheetActivity<PaymentSheetResult>() {
                 viewModel::onGooglePayResult
             )
         )
-        viewModel.maybeFetchStripeIntent()
+
+        // If the activity was destroyed we need to restore the payment intent without triggering
+        // the transition (which would replace the existing fragment).  The button container
+        // and buy button visibility must be visible again.
+        when (savedInstanceState?.getBoolean(SAVE_IS_PAYMENT_INTENT_TYPE)) {
+            true -> savedInstanceState.getParcelable<PaymentIntent>(SAVE_STRIPE_INTENT)
+            false -> savedInstanceState.getParcelable<SetupIntent>(SAVE_STRIPE_INTENT)
+            null -> null
+        }?.let {
+            // The buy btton needs to be made visible since it is gone in the xml
+            viewModel.setStripeIntent(it)
+            buttonContainer.isVisible = true
+            viewBinding.buyButton.isVisible = true
+        } ?: run {
+            viewModel.maybeFetchStripeIntent()
+        }
 
         starterArgs.statusBarColor?.let {
             window.statusBarColor = it
@@ -176,6 +193,12 @@ internal class PaymentSheetActivity : BaseSheetActivity<PaymentSheetResult>() {
         super.onBackPressed()
     }
 
+    override fun onSaveInstanceState(outState: Bundle) {
+        outState.putParcelable(SAVE_STRIPE_INTENT, viewModel.stripeIntent.value)
+        outState.putBoolean(SAVE_IS_PAYMENT_INTENT_TYPE, viewModel.isProcessingPaymentIntent)
+        super.onSaveInstanceState(outState)
+    }
+
     private fun updateErrorMessage(userMessage: BaseSheetViewModel.UserErrorMessage? = null) {
         messageView.isVisible = userMessage != null
         messageView.text = userMessage?.message
@@ -306,6 +329,11 @@ internal class PaymentSheetActivity : BaseSheetActivity<PaymentSheetResult>() {
     }
 
     internal companion object {
+
+        private const val SAVE_STRIPE_INTENT =
+            "com.stripe.android.paymentsheet.paymentsheetactivity.save_stripe_intent"
+        private const val SAVE_IS_PAYMENT_INTENT_TYPE =
+            "com.stripe.android.paymentsheet.paymentsheetactivity.save_stripe_intent_type"
         internal const val EXTRA_FRAGMENT_CONFIG = BaseSheetActivity.EXTRA_FRAGMENT_CONFIG
         internal const val EXTRA_STARTER_ARGS = BaseSheetActivity.EXTRA_STARTER_ARGS
     }