Show error notification when backup fails

The implementation is rudimentary for now.
E.g. The notification is only shown when a device init fails
which seems to be triggered after the first failure.

app/src/main/java/com/stevesoltys/backup/Backup.kt

@@ -5,6 +5,7 @@ import android.app.Application
 import android.app.backup.IBackupManager
 import android.content.Context.BACKUP_SERVICE
 import android.content.pm.PackageManager.PERMISSION_GRANTED
+import android.net.Uri
 import android.os.Build
 import android.os.ServiceManager.getService
 import android.util.Log
@@ -14,6 +15,8 @@ import com.stevesoltys.backup.settings.getDeviceName
 import com.stevesoltys.backup.settings.setDeviceName
 import io.github.novacrypto.hashing.Sha256.sha256Twice
 
+private const val URI_AUTHORITY_EXTERNAL_STORAGE = "com.android.externalstorage.documents"
+
 private val TAG = Backup::class.java.simpleName
 
 /**
@@ -31,6 +34,10 @@ class Backup : Application() {
         }
     }
 
+    val notificationManager by lazy {
+        BackupNotificationManager(this)
+    }
+
     override fun onCreate() {
         super.onCreate()
         storeDeviceName()
@@ -53,3 +60,5 @@ class Backup : Application() {
     }
 
 }
+
+fun Uri.isOnExternalStorage() = authority == URI_AUTHORITY_EXTERNAL_STORAGE

app/src/main/java/com/stevesoltys/backup/BackupNotificationManager.kt

@@ -0,0 +1,93 @@
+package com.stevesoltys.backup
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.NotificationManager.IMPORTANCE_DEFAULT
+import android.app.NotificationManager.IMPORTANCE_LOW
+import android.app.PendingIntent
+import android.app.backup.BackupTransport.TRANSPORT_PACKAGE_REJECTED
+import android.content.Context
+import android.content.Intent
+import androidx.core.app.NotificationCompat.*
+import com.stevesoltys.backup.settings.SettingsActivity
+
+private const val CHANNEL_ID_OBSERVER = "NotificationBackupObserver"
+private const val CHANNEL_ID_ERROR = "NotificationError"
+private const val NOTIFICATION_ID_OBSERVER = 1
+private const val NOTIFICATION_ID_ERROR = 2
+
+class BackupNotificationManager(private val context: Context) {
+
+    private val nm = context.getSystemService(NotificationManager::class.java)!!.apply {
+        createNotificationChannel(getObserverChannel())
+        createNotificationChannel(getErrorChannel())
+    }
+
+    private fun getObserverChannel(): NotificationChannel {
+        val title = context.getString(R.string.notification_channel_title)
+        return NotificationChannel(CHANNEL_ID_OBSERVER, title, IMPORTANCE_LOW).apply {
+            enableVibration(false)
+        }
+    }
+
+    private fun getErrorChannel(): NotificationChannel {
+        val title = context.getString(R.string.notification_error_channel_title)
+        return NotificationChannel(CHANNEL_ID_ERROR, title, IMPORTANCE_DEFAULT)
+    }
+
+    private val observerBuilder = Builder(context, CHANNEL_ID_OBSERVER).apply {
+        setSmallIcon(R.drawable.ic_cloud_upload)
+    }
+
+    private val errorBuilder = Builder(context, CHANNEL_ID_ERROR).apply {
+        setSmallIcon(R.drawable.ic_cloud_error)
+    }
+
+    fun onBackupUpdate(app: CharSequence, transferred: Int, expected: Int, userInitiated: Boolean) {
+        val notification = observerBuilder.apply {
+            setContentTitle(context.getString(R.string.notification_title))
+            setContentText(app)
+            setProgress(expected, transferred, false)
+            priority = if (userInitiated) PRIORITY_DEFAULT else PRIORITY_LOW
+        }.build()
+        nm.notify(NOTIFICATION_ID_OBSERVER, notification)
+    }
+
+    fun onBackupResult(app: CharSequence, status: Int, userInitiated: Boolean) {
+        val title = context.getString(when (status) {
+            0 -> R.string.notification_backup_result_complete
+            TRANSPORT_PACKAGE_REJECTED -> R.string.notification_backup_result_rejected
+            else -> R.string.notification_backup_result_error
+        })
+        val notification = observerBuilder.apply {
+            setContentTitle(title)
+            setContentText(app)
+            priority = if (userInitiated) PRIORITY_DEFAULT else PRIORITY_LOW
+        }.build()
+        nm.notify(NOTIFICATION_ID_OBSERVER, notification)
+    }
+
+    fun onBackupFinished() {
+        nm.cancel(NOTIFICATION_ID_OBSERVER)
+    }
+
+    fun onBackupError() {
+        val intent = Intent(context, SettingsActivity::class.java)
+        val pendingIntent = PendingIntent.getActivity(context, 0, intent, 0)
+        val actionText = context.getString(R.string.notification_error_action)
+        val action = Action(R.drawable.ic_storage, actionText, pendingIntent)
+        val notification = errorBuilder.apply {
+            setContentTitle(context.getString(R.string.notification_error_title))
+            setContentText(context.getString(R.string.notification_error_text))
+            addAction(action)
+            setOnlyAlertOnce(true)
+            setAutoCancel(true)
+        }.build()
+        nm.notify(NOTIFICATION_ID_ERROR, notification)
+    }
+
+    fun onBackupErrorSeen() {
+        nm.cancel(NOTIFICATION_ID_ERROR)
+    }
+
+}

app/src/main/java/com/stevesoltys/backup/NotificationBackupObserver.kt

@@ -1,40 +1,18 @@
 package com.stevesoltys.backup
 
-import android.app.NotificationChannel
-import android.app.NotificationManager
-import android.app.NotificationManager.IMPORTANCE_LOW
 import android.app.backup.BackupProgress
-import android.app.backup.BackupTransport.TRANSPORT_PACKAGE_REJECTED
 import android.app.backup.IBackupObserver
 import android.content.Context
 import android.util.Log
 import android.util.Log.INFO
 import android.util.Log.isLoggable
-import androidx.core.app.NotificationCompat
-import androidx.core.app.NotificationCompat.PRIORITY_DEFAULT
-import androidx.core.app.NotificationCompat.PRIORITY_LOW
-
-private const val CHANNEL_ID = "NotificationBackupObserver"
-private const val NOTIFICATION_ID = 1042
 
 private val TAG = NotificationBackupObserver::class.java.simpleName
 
-class NotificationBackupObserver(
+class NotificationBackupObserver(context: Context, private val userInitiated: Boolean) : IBackupObserver.Stub() {
-        private val context: Context,
-        private val userInitiated: Boolean) : IBackupObserver.Stub() {
 
     private val pm = context.packageManager
-    private val nm = context.getSystemService(NotificationManager::class.java).apply {
+    private val nm = (context.applicationContext as Backup).notificationManager
-        val title = context.getString(R.string.notification_channel_title)
-        val channel = NotificationChannel(CHANNEL_ID, title, IMPORTANCE_LOW).apply {
-            enableVibration(false)
-        }
-        createNotificationChannel(channel)
-    }
-    private val notificationBuilder = NotificationCompat.Builder(context, CHANNEL_ID).apply {
-        setSmallIcon(R.drawable.ic_cloud_upload)
-        priority = if (userInitiated) PRIORITY_DEFAULT else PRIORITY_LOW
-    }
 
     /**
      * This method could be called several times for packages with full data backup.
@@ -44,17 +22,13 @@ class NotificationBackupObserver(
      * @param backupProgress Current progress of backup for the package.
      */
     override fun onUpdate(currentBackupPackage: String, backupProgress: BackupProgress) {
-        val transferred = backupProgress.bytesTransferred
+        val transferred = backupProgress.bytesTransferred.toInt()
-        val expected = backupProgress.bytesExpected
+        val expected = backupProgress.bytesExpected.toInt()
         if (isLoggable(TAG, INFO)) {
             Log.i(TAG, "Update. Target: $currentBackupPackage, $transferred/$expected")
         }
-        val notification = notificationBuilder.apply {
+        val app = getAppName(currentBackupPackage)
-            setContentTitle(context.getString(R.string.notification_title))
+        nm.onBackupUpdate(app, transferred, expected, userInitiated)
-            setContentText(getAppName(currentBackupPackage))
-            setProgress(expected.toInt(), transferred.toInt(), false)
-        }.build()
-        nm.notify(NOTIFICATION_ID, notification)
     }
 
     /**
@@ -71,16 +45,7 @@ class NotificationBackupObserver(
         if (isLoggable(TAG, INFO)) {
             Log.i(TAG, "Completed. Target: $target, status: $status")
         }
-        val title = context.getString(when (status) {
+        nm.onBackupResult(getAppName(target), status, userInitiated)
-            0 -> R.string.notification_backup_result_complete
-            TRANSPORT_PACKAGE_REJECTED -> R.string.notification_backup_result_rejected
-            else -> R.string.notification_backup_result_error
-        })
-        val notification = notificationBuilder.apply {
-            setContentTitle(title)
-            setContentText(getAppName(target))
-        }.build()
-        nm.notify(NOTIFICATION_ID, notification)
     }
 
     /**
@@ -94,7 +59,7 @@ class NotificationBackupObserver(
         if (isLoggable(TAG, INFO)) {
             Log.i(TAG, "Backup finished. Status: $status")
         }
-        nm.cancel(NOTIFICATION_ID)
+        nm.onBackupFinished()
     }
 
     private fun getAppName(packageId: String): CharSequence {

app/src/main/java/com/stevesoltys/backup/settings/SettingsActivity.kt

@@ -7,6 +7,7 @@ import android.view.MenuItem
 import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.ViewModelProviders
+import com.stevesoltys.backup.Backup
 import com.stevesoltys.backup.LiveEventHandler
 import com.stevesoltys.backup.R
 
@@ -25,8 +26,8 @@ class SettingsActivity : AppCompatActivity() {
         setContentView(R.layout.activity_settings)
 
         viewModel = ViewModelProviders.of(this).get(SettingsViewModel::class.java)
-        viewModel.onLocationSet.observeEvent(this, LiveEventHandler { wasEmptyBefore ->
+        viewModel.onLocationSet.observeEvent(this, LiveEventHandler { initialSetUp ->
-            if (wasEmptyBefore) showFragment(SettingsFragment())
+            if (initialSetUp) showFragment(SettingsFragment())
             else supportFragmentManager.popBackStack()
         })
         viewModel.chooseBackupLocation.observeEvent(this, LiveEventHandler { show ->
@@ -54,8 +55,10 @@ class SettingsActivity : AppCompatActivity() {
         // check that backup is provisioned
         if (!viewModel.recoveryCodeIsSet()) {
             showRecoveryCodeActivity()
-        } else if (!viewModel.locationIsSet()) {
+        } else if (!viewModel.validLocationIsSet()) {
             showFragment(BackupLocationFragment())
+            // remove potential error notifications
+            (application as Backup).notificationManager.onBackupErrorSeen()
         }
     }
 

app/src/main/java/com/stevesoltys/backup/settings/SettingsViewModel.kt

@@ -5,10 +5,12 @@ import android.content.Intent
 import android.content.Intent.FLAG_GRANT_READ_URI_PERMISSION
 import android.content.Intent.FLAG_GRANT_WRITE_URI_PERMISSION
 import android.util.Log
+import androidx.documentfile.provider.DocumentFile
 import androidx.lifecycle.AndroidViewModel
 import com.stevesoltys.backup.Backup
 import com.stevesoltys.backup.LiveEvent
 import com.stevesoltys.backup.MutableLiveEvent
+import com.stevesoltys.backup.isOnExternalStorage
 import com.stevesoltys.backup.transport.ConfigurableBackupTransportService
 import com.stevesoltys.backup.transport.requestBackup
 
@@ -30,7 +32,13 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
     internal fun chooseBackupLocation() = mChooseBackupLocation.setEvent(true)
 
     fun recoveryCodeIsSet() = Backup.keyManager.hasBackupKey()
-    fun locationIsSet() = getBackupFolderUri(getApplication()) != null
+
+    fun validLocationIsSet(): Boolean {
+        val uri = getBackupFolderUri(app) ?: return false
+        if (uri.isOnExternalStorage()) return true  // might be a temporary failure
+        val file = DocumentFile.fromTreeUri(app, uri) ?: return false
+        return file.isDirectory
+    }
 
     fun handleChooseFolderResult(result: Intent?) {
         val folderUri = result?.data ?: return
@@ -40,13 +48,13 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
         app.contentResolver.takePersistableUriPermission(folderUri, takeFlags)
 
         // check if this is initial set-up or a later change
-        val wasEmptyBefore = getBackupFolderUri(app) == null
+        val initialSetUp = !validLocationIsSet()
 
         // store backup folder location in settings
         setBackupFolderUri(app, folderUri)
 
         // notify the UI that the location has been set
-        locationWasSet.setEvent(wasEmptyBefore)
+        locationWasSet.setEvent(initialSetUp)
 
         // stop backup service to be sure the old location will get updated
         app.stopService(Intent(app, ConfigurableBackupTransportService::class.java))

app/src/main/java/com/stevesoltys/backup/transport/PluginManager.kt

@@ -36,8 +36,9 @@ class PluginManager(context: Context) {
     private val inputFactory = InputFactory()
     private val kvBackup = KVBackup(backupPlugin.kvBackupPlugin, inputFactory, headerWriter, crypto)
     private val fullBackup = FullBackup(backupPlugin.fullBackupPlugin, inputFactory, headerWriter, crypto)
+    private val notificationManager = (context.applicationContext as Backup).notificationManager
 
-    internal val backupCoordinator = BackupCoordinator(backupPlugin, kvBackup, fullBackup)
+    internal val backupCoordinator = BackupCoordinator(backupPlugin, kvBackup, fullBackup, notificationManager)
 
 
     private val restorePlugin = DocumentsProviderRestorePlugin(storage)

app/src/main/java/com/stevesoltys/backup/transport/backup/BackupCoordinator.kt

@@ -5,6 +5,7 @@ import android.app.backup.BackupTransport.TRANSPORT_OK
 import android.content.pm.PackageInfo
 import android.os.ParcelFileDescriptor
 import android.util.Log
+import com.stevesoltys.backup.BackupNotificationManager
 import java.io.IOException
 
 private val TAG = BackupCoordinator::class.java.simpleName
@@ -16,7 +17,8 @@ private val TAG = BackupCoordinator::class.java.simpleName
 class BackupCoordinator(
         private val plugin: BackupPlugin,
         private val kv: KVBackup,
-        private val full: FullBackup) {
+        private val full: FullBackup,
+        private val nm: BackupNotificationManager) {
 
     private var calledInitialize = false
     private var calledClearBackupData = false
@@ -53,6 +55,7 @@ class BackupCoordinator(
             TRANSPORT_OK
         } catch (e: IOException) {
             Log.e(TAG, "Error initializing device", e)
+            nm.onBackupError()
             TRANSPORT_ERROR
         }
     }

app/src/main/res/drawable/ic_cloud_error.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="?android:attr/textColorSecondary"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M19,20H6C2.71,20 0,17.29 0,14C0,10.9 2.34,8.36 5.35,8.03C6.6,5.64 9.11,4 12,4C15.64,4 18.67,6.59 19.35,10.03C21.95,10.22 24,12.36 24,15C24,17.74 21.74,20 19,20M11,15V17H13V15H11M11,13H13V8H11V13Z" />
+</vector>

app/src/main/res/values/strings.xml

@@ -65,4 +65,9 @@
     <string name="notification_backup_result_rejected">Not backed up</string>
     <string name="notification_backup_result_error">Backup failed</string>
 
+    <string name="notification_error_channel_title">Error Notification</string>
+    <string name="notification_error_title">Backup Error</string>
+    <string name="notification_error_text">A device backup failed to run.</string>
+    <string name="notification_error_action">Fix</string>
+
 </resources>

app/src/test/java/com/stevesoltys/backup/transport/CoordinatorIntegrationTest.kt

@@ -7,6 +7,7 @@ import android.app.backup.BackupTransport.TRANSPORT_OK
 import android.app.backup.RestoreDescription
 import android.app.backup.RestoreDescription.TYPE_FULL_STREAM
 import android.os.ParcelFileDescriptor
+import com.stevesoltys.backup.BackupNotificationManager
 import com.stevesoltys.backup.crypto.CipherFactoryImpl
 import com.stevesoltys.backup.crypto.CryptoImpl
 import com.stevesoltys.backup.crypto.KeyManagerTestImpl
@@ -37,7 +38,8 @@ internal class CoordinatorIntegrationTest : TransportTest() {
     private val kvBackup = KVBackup(kvBackupPlugin, inputFactory, headerWriter, cryptoImpl)
     private val fullBackupPlugin = mockk<FullBackupPlugin>()
     private val fullBackup = FullBackup(fullBackupPlugin, inputFactory, headerWriter, cryptoImpl)
-    private val backup = BackupCoordinator(backupPlugin, kvBackup, fullBackup)
+    private val notificationManager = mockk<BackupNotificationManager>()
+    private val backup = BackupCoordinator(backupPlugin, kvBackup, fullBackup, notificationManager)
 
     private val restorePlugin = mockk<RestorePlugin>()
     private val kvRestorePlugin = mockk<KVRestorePlugin>()

app/src/test/java/com/stevesoltys/backup/transport/backup/BackupCoordinatorTest.kt

@@ -2,6 +2,7 @@ package com.stevesoltys.backup.transport.backup
 
 import android.app.backup.BackupTransport.TRANSPORT_ERROR
 import android.app.backup.BackupTransport.TRANSPORT_OK
+import com.stevesoltys.backup.BackupNotificationManager
 import io.mockk.Runs
 import io.mockk.every
 import io.mockk.just
@@ -17,8 +18,9 @@ internal class BackupCoordinatorTest: BackupTest() {
     private val plugin = mockk<BackupPlugin>()
     private val kv = mockk<KVBackup>()
     private val full = mockk<FullBackup>()
+    private val notificationManager = mockk<BackupNotificationManager>()
 
-    private val backup = BackupCoordinator(plugin, kv, full)
+    private val backup = BackupCoordinator(plugin, kv, full, notificationManager)
 
     @Test
     fun `device initialization succeeds and delegates to plugin`() {
@@ -33,6 +35,7 @@ internal class BackupCoordinatorTest: BackupTest() {
     @Test
     fun `device initialization fails`() {
         every { plugin.initializeDevice() } throws IOException()
+        every { notificationManager.onBackupError() } just Runs
 
         assertEquals(TRANSPORT_ERROR, backup.initializeDevice())
 

build.gradle

@@ -2,7 +2,7 @@
 
 buildscript {
 
-    ext.kotlin_version = '1.3.41'
+    ext.kotlin_version = '1.3.50'
 
     repositories {
         jcenter()