Request permission to post notifications on devices running Android 13 and above (#68)

* Add user permission to post notifications in manifest

* Add effect to check permission to post notifications

* Check permission to post notification, when screen is created and restored

* Add view effect to request notification permission

* Request notification permission when it's not granted

* Extract out notification permission launcher as class property

Author: msasikanth

app/src/main/AndroidManifest.xml

@@ -3,6 +3,7 @@
   xmlns:tools="http://schemas.android.com/tools">
 
   <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
+  <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
 
   <application
     android:name=".PinnitApp"

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationScreenViewEffect.kt

@@ -5,3 +5,5 @@ import java.util.UUID
 sealed class NotificationScreenViewEffect
 
 data class UndoNotificationDeleteViewEffect(val notificationUuid: UUID) : NotificationScreenViewEffect()
+
+object RequestNotificationPermissionViewEffect : NotificationScreenViewEffect()

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationsScreen.kt

@@ -1,9 +1,12 @@
 package dev.sasikanth.pinnit.notifications
 
+import android.Manifest
+import android.annotation.SuppressLint
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.core.view.doOnPreDraw
 import androidx.core.view.isGone
 import androidx.core.view.isVisible
@@ -65,6 +68,11 @@ class NotificationsScreen : Fragment(), NotificationsScreenUi {
     }
   }
 
+  private val notificationPermissionLauncher = registerForActivityResult(ActivityResultContracts.RequestPermission()) { _ ->
+    // At the moment we are not handling permission results. Since this is a notification app
+    // expecting users to provide the notification permission for app to work
+  }
+
   private var _binding: FragmentNotificationsBinding? = null
   private val binding get() = _binding!!
 
@@ -135,7 +143,10 @@ class NotificationsScreen : Fragment(), NotificationsScreenUi {
           }
           .show()
       }
-      else -> throw IllegalArgumentException("Unknown view effect: $viewEffect")
+
+      RequestNotificationPermissionViewEffect -> requestNotificationPermission()
+
+      null -> throw NullPointerException()
     }
   }
 
@@ -166,6 +177,11 @@ class NotificationsScreen : Fragment(), NotificationsScreenUi {
     adapter.submitList(null)
   }
 
+  @SuppressLint("InlinedApi")
+  private fun requestNotificationPermission() {
+    notificationPermissionLauncher.launch(Manifest.permission.POST_NOTIFICATIONS)
+  }
+
   private fun onToggleNotificationPinClicked(notification: PinnitNotification) {
     viewModel.dispatchEvent(TogglePinStatusClicked(notification))
   }

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationsScreenEffect.kt

@@ -22,3 +22,7 @@ data class CancelNotificationSchedule(val notificationId: UUID) : NotificationsS
 data class RemoveSchedule(val notificationId: UUID) : NotificationsScreenEffect()
 
 data class ScheduleNotification(val notification: PinnitNotification) : NotificationsScreenEffect()
+
+object CheckPermissionToPostNotification : NotificationsScreenEffect()
+
+object RequestNotificationPermission : NotificationsScreenEffect()

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationsScreenEffectHandler.kt

@@ -44,9 +44,18 @@ class NotificationsScreenEffectHandler @AssistedInject constructor(
       is RemoveSchedule -> removeSchedule(effect, dispatchEvent)
 
       is ScheduleNotification -> pinnitNotificationScheduler.scheduleNotification(effect.notification)
+
+      CheckPermissionToPostNotification -> checkPermissionToPostNotification(dispatchEvent)
+
+      RequestNotificationPermission -> viewEffectConsumer.accept(RequestNotificationPermissionViewEffect)
     }
   }
 
+  private fun checkPermissionToPostNotification(dispatchEvent: (NotificationsScreenEvent) -> Unit) {
+    val canPostNotifications = notificationUtil.hasPermissionToPostNotifications()
+    dispatchEvent(HasPermissionToPostNotifications(canPostNotifications))
+  }
+
   private fun loadNotifications(dispatchEvent: (NotificationsScreenEvent) -> Unit) {
     val notificationsFlow = notificationRepository.notifications()
     notificationsFlow

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationsScreenEvent.kt

@@ -20,3 +20,5 @@ data class RemovedNotificationSchedule(val notificationId: UUID) : Notifications
 data class RemoveNotificationScheduleClicked(val notificationId: UUID) : NotificationsScreenEvent()
 
 data class RestoredDeletedNotification(val notification: PinnitNotification) : NotificationsScreenEvent()
+
+data class HasPermissionToPostNotifications(val canPostNotifications: Boolean) : NotificationsScreenEvent()

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationsScreenInit.kt

@@ -7,15 +7,15 @@ import javax.inject.Inject
 
 class NotificationsScreenInit @Inject constructor() : Init<NotificationsScreenModel, NotificationsScreenEffect> {
   override fun init(model: NotificationsScreenModel): First<NotificationsScreenModel, NotificationsScreenEffect> {
-    val effects = if (model.notificationsQueried.not()) {
+    val effects = mutableSetOf<NotificationsScreenEffect>(CheckPermissionToPostNotification)
+
+    if (model.notificationsQueried.not()) {
       // We are only checking for notifications visibility during
       // screen create because system notifications are disappear only
       // if the app is force closed (or when updating). So app needs
       // to be reopened again. Notifications will persist
       // orientation changes, so no point checking again.
-      setOf(LoadNotifications, CheckNotificationsVisibility)
-    } else {
-      emptySet()
+      effects.addAll(listOf(LoadNotifications, CheckNotificationsVisibility))
     }
 
     return first(model, effects)

app/src/main/java/dev/sasikanth/pinnit/notifications/NotificationsScreenUpdate.kt

@@ -3,6 +3,7 @@ package dev.sasikanth.pinnit.notifications
 import com.spotify.mobius.Next
 import com.spotify.mobius.Next.dispatch
 import com.spotify.mobius.Next.next
+import com.spotify.mobius.Next.noChange
 import com.spotify.mobius.Update
 import javax.inject.Inject
 
@@ -17,6 +18,15 @@ class NotificationsScreenUpdate @Inject constructor() : Update<NotificationsScre
       is RemovedNotificationSchedule -> dispatch(setOf(CancelNotificationSchedule(event.notificationId)))
       is RemoveNotificationScheduleClicked -> dispatch(setOf(RemoveSchedule(event.notificationId)))
       is RestoredDeletedNotification -> dispatch(setOf(ScheduleNotification(event.notification)))
+      is HasPermissionToPostNotifications -> hasPermissionToPostNotifications(event.canPostNotifications)
+    }
+  }
+
+  private fun hasPermissionToPostNotifications(canPostNotifications: Boolean): Next<NotificationsScreenModel, NotificationsScreenEffect> {
+    return if (!canPostNotifications) {
+      dispatch(setOf(RequestNotificationPermission))
+    } else {
+      noChange()
     }
   }
 

app/src/main/java/dev/sasikanth/pinnit/utils/notification/NotificationUtil.kt

@@ -1,15 +1,18 @@
 package dev.sasikanth.pinnit.utils.notification
 
+import android.Manifest
 import android.app.Notification
 import android.app.NotificationChannel
 import android.app.NotificationManager
 import android.app.PendingIntent
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.os.Build
 import androidx.core.app.NotificationCompat
 import androidx.core.app.NotificationCompat.Action
 import androidx.core.app.NotificationManagerCompat
+import androidx.core.content.ContextCompat
 import androidx.core.content.getSystemService
 import androidx.navigation.NavDeepLinkBuilder
 import dagger.hilt.android.qualifiers.ApplicationContext
@@ -77,6 +80,15 @@ class NotificationUtil @Inject constructor(
     }
   }
 
+  /**
+   * Check if the app has permission to post notifications on devices running Android version >= 13
+   */
+  fun hasPermissionToPostNotifications() = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+    ContextCompat.checkSelfPermission(context, Manifest.permission.POST_NOTIFICATIONS) == PackageManager.PERMISSION_GRANTED
+  } else {
+    true
+  }
+
   private fun buildSystemNotification(notification: PinnitNotification): Notification {
     val content = notification.content.orEmpty()
     val editorScreenArgs = EditorScreenArgs(

app/src/test/java/dev/sasikanth/pinnit/notifications/NotificationsScreenEffectHandlerTest.kt

@@ -8,10 +8,8 @@ import com.nhaarman.mockitokotlin2.verifyNoMoreInteractions
 import com.nhaarman.mockitokotlin2.whenever
 import com.spotify.mobius.Connection
 import com.spotify.mobius.test.RecordingConsumer
-import dev.sasikanth.sharedtestcode.TestData
 import dev.sasikanth.pinnit.scheduler.PinnitNotificationScheduler
 import dev.sasikanth.pinnit.utils.TestDispatcherProvider
-import dev.sasikanth.sharedtestcode.utils.TestUtcClock
 import dev.sasikanth.pinnit.utils.notification.NotificationUtil
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.test.TestCoroutineScope
@@ -273,4 +271,29 @@ class NotificationsScreenEffectHandlerTest {
     verify(pinnitNotificationScheduler).scheduleNotification(notification)
     verifyNoMoreInteractions(pinnitNotificationScheduler)
   }
+
+  @Test
+  fun `when check notifications permission effect is received, then check the permission`() {
+    // given
+    whenever(notificationUtil.hasPermissionToPostNotifications()) doReturn true
+
+    // when
+    connection.accept(CheckPermissionToPostNotification)
+
+    // then
+    consumer.assertValues(HasPermissionToPostNotifications(canPostNotifications = true))
+
+    verify(notificationUtil).hasPermissionToPostNotifications()
+    verifyNoMoreInteractions(notificationUtil)
+  }
+
+  @Test
+  fun `when request notification permission effect is received, then request permission to post notifications`() {
+    // when
+    connection.accept(RequestNotificationPermission)
+
+    // then
+    consumer.assertValues()
+    viewActionsConsumer.accept(RequestNotificationPermissionViewEffect)
+  }
 }