catching remove pusher errors in the notification targets screen

- displays a dialog with a human readable version of the error

vector/src/main/java/im/vector/app/features/settings/push/PushGatewayViewEvents.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2021 New Vector Ltd
+ *
+ * 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 im.vector.app.features.settings.push
+
+import im.vector.app.core.platform.VectorViewEvents
+
+sealed class PushGatewayViewEvents : VectorViewEvents {
+    data class RemovePusherFailed(val cause: Throwable): PushGatewayViewEvents()
+}

vector/src/main/java/im/vector/app/features/settings/push/PushGatewaysFragment.kt

@@ -24,9 +24,11 @@ import android.view.ViewGroup
 import androidx.appcompat.app.AppCompatActivity
 import com.airbnb.mvrx.fragmentViewModel
 import com.airbnb.mvrx.withState
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import im.vector.app.R
 import im.vector.app.core.extensions.cleanup
 import im.vector.app.core.extensions.configureWith
+import im.vector.app.core.extensions.exhaustive
 import im.vector.app.core.platform.VectorBaseFragment
 import im.vector.app.databinding.FragmentGenericRecyclerBinding
 import org.matrix.android.sdk.api.session.pushers.Pusher
@@ -69,6 +71,17 @@ class PushGatewaysFragment @Inject constructor(
             override fun onRemovePushTapped(pusher: Pusher) = viewModel.handle(PushGatewayAction.RemovePusher(pusher))
         }
         views.genericRecyclerView.configureWith(epoxyController, dividerDrawable = R.drawable.divider_horizontal)
+        viewModel.observeViewEvents {
+            when(it) {
+                is PushGatewayViewEvents.RemovePusherFailed -> {
+                    MaterialAlertDialogBuilder(requireContext())
+                            .setTitle(R.string.dialog_title_error)
+                            .setMessage(errorFormatter.toHumanReadable(it.cause))
+                            .setPositiveButton(android.R.string.ok, null)
+                            .show()
+                }
+            }.exhaustive
+        }
     }
 
     override fun onDestroyView() {

vector/src/main/java/im/vector/app/features/settings/push/PushGatewaysViewModel.kt

@@ -29,6 +29,7 @@ import dagger.assisted.AssistedFactory
 import im.vector.app.core.extensions.exhaustive
 import im.vector.app.core.platform.EmptyViewEvents
 import im.vector.app.core.platform.VectorViewModel
+import im.vector.app.features.home.HomeActivityViewEvents
 import kotlinx.coroutines.launch
 import org.matrix.android.sdk.api.session.Session
 import org.matrix.android.sdk.api.session.pushers.Pusher
@@ -40,7 +41,7 @@ data class PushGatewayViewState(
 
 class PushGatewaysViewModel @AssistedInject constructor(@Assisted initialState: PushGatewayViewState,
                                                         private val session: Session)
-    : VectorViewModel<PushGatewayViewState, PushGatewayAction, EmptyViewEvents>(initialState) {
+    : VectorViewModel<PushGatewayViewState, PushGatewayAction, PushGatewayViewEvents>(initialState) {
 
     @AssistedFactory
     interface Factory {
@@ -79,7 +80,11 @@ class PushGatewaysViewModel @AssistedInject constructor(@Assisted initialState:
 
     private fun removePusher(pusher: Pusher) {
         viewModelScope.launch {
-            session.removePusher(pusher.pushKey, pusher.appId)
+            kotlin.runCatching {
+                session.removePusher(pusher.pushKey, pusher.appId)
+            }.onFailure {
+                _viewEvents.post(PushGatewayViewEvents.RemovePusherFailed(it))
+            }
         }
     }