Add a RestoreActivity that lists available RestoreSets (backups)

and allows the user to select one to get restored.

app/src/main/AndroidManifest.xml

@@ -32,9 +32,20 @@
             android:exported="true" />
 
         <activity
-            android:name=".settings.RecoveryCodeActivity"
+            android:name=".ui.RecoveryCodeActivity"
             android:label="@string/recovery_code_title" />
 
+        <activity
+            android:name=".restore.RestoreActivity"
+            android:exported="true"
+            android:label="@string/restore_title"
+            android:theme="@style/AppTheme.NoActionBar">
+            <intent-filter>
+                <action android:name="com.stevesoltys.backup.restore.RESTORE_BACKUP" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </activity>
+
         <activity
             android:name="com.stevesoltys.backup.activity.MainActivity"
             android:label="@string/app_name" />

app/src/main/java/com/stevesoltys/backup/restore/RestoreActivity.kt

@@ -0,0 +1,30 @@
+package com.stevesoltys.backup.restore
+
+import android.os.Bundle
+import androidx.lifecycle.ViewModelProviders
+import com.stevesoltys.backup.R
+import com.stevesoltys.backup.ui.BackupActivity
+import com.stevesoltys.backup.ui.BackupViewModel
+
+class RestoreActivity : BackupActivity() {
+
+    private lateinit var viewModel: RestoreViewModel
+
+    override fun getViewModel(): BackupViewModel = viewModel
+
+    override fun getInitialFragment() = RestoreSetFragment()
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        viewModel = ViewModelProviders.of(this).get(RestoreViewModel::class.java)
+        super.onCreate(savedInstanceState)
+
+        setContentView(R.layout.activity_fragment_container)
+
+        if (savedInstanceState == null) showFragment(getInitialFragment())
+    }
+
+    override fun onInvalidLocation() {
+        // TODO alert dialog?
+    }
+
+}

app/src/main/java/com/stevesoltys/backup/restore/RestoreSetAdapter.kt

@@ -0,0 +1,42 @@
+package com.stevesoltys.backup.restore
+
+import android.app.backup.RestoreSet
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.recyclerview.widget.RecyclerView.Adapter
+import androidx.recyclerview.widget.RecyclerView.ViewHolder
+import com.stevesoltys.backup.R
+import com.stevesoltys.backup.restore.RestoreSetAdapter.RestoreSetViewHolder
+
+internal class RestoreSetAdapter(
+        private val listener: RestoreSetClickListener,
+        private val items: Array<out RestoreSet>) : Adapter<RestoreSetViewHolder>() {
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RestoreSetViewHolder {
+        val v = LayoutInflater.from(parent.context)
+                .inflate(R.layout.list_item_restore_set, parent, false) as View
+        return RestoreSetViewHolder(v)
+    }
+
+    override fun getItemCount() = items.size
+
+    override fun onBindViewHolder(holder: RestoreSetViewHolder, position: Int) {
+        holder.bind(items[position])
+    }
+
+    inner class RestoreSetViewHolder(private val v: View) : ViewHolder(v) {
+
+        private val titleView = v.findViewById<TextView>(R.id.titleView)
+        private val subtitleView = v.findViewById<TextView>(R.id.subtitleView)
+
+        internal fun bind(item: RestoreSet) {
+            v.setOnClickListener { listener.onRestoreSetClicked(item) }
+            titleView.text = item.name
+            subtitleView.text = item.device
+        }
+
+    }
+
+}

app/src/main/java/com/stevesoltys/backup/restore/RestoreSetFragment.kt

@@ -0,0 +1,64 @@
+package com.stevesoltys.backup.restore
+
+import android.app.backup.RestoreSet
+import android.os.Bundle
+import android.util.Log
+import android.view.LayoutInflater
+import android.view.View
+import android.view.View.INVISIBLE
+import android.view.View.VISIBLE
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.Observer
+import androidx.lifecycle.ViewModelProviders
+import com.stevesoltys.backup.R
+import kotlinx.android.synthetic.main.fragment_restore_set.*
+
+class RestoreSetFragment : Fragment(), RestoreSetClickListener {
+
+    private lateinit var viewModel: RestoreViewModel
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
+                              savedInstanceState: Bundle?): View? {
+        return inflater.inflate(R.layout.fragment_restore_set, container, false)
+    }
+
+    override fun onActivityCreated(savedInstanceState: Bundle?) {
+        super.onActivityCreated(savedInstanceState)
+        viewModel = ViewModelProviders.of(requireActivity()).get(RestoreViewModel::class.java)
+
+        viewModel.restoreSets.observe(this, Observer { result -> onRestoreSetsLoaded(result) })
+
+        backView.setOnClickListener { requireActivity().finishAfterTransition() }
+    }
+
+    override fun onStart() {
+        super.onStart()
+        viewModel.loadRestoreSets()
+    }
+
+    private fun onRestoreSetsLoaded(result: RestoreSetResult) {
+        if (result.hasError()) {
+            errorView.visibility = VISIBLE
+            listView.visibility = INVISIBLE
+            progressBar.visibility = INVISIBLE
+
+            errorView.text = result.errorMsg
+        } else {
+            errorView.visibility = INVISIBLE
+            listView.visibility = VISIBLE
+            progressBar.visibility = INVISIBLE
+
+            listView.adapter = RestoreSetAdapter(this, result.sets)
+        }
+    }
+
+    override fun onRestoreSetClicked(set: RestoreSet) {
+        Log.e("TEST", "RESTORE SET CLICKED: ${set.name} ${set.device} ${set.token}")
+    }
+
+}
+
+internal interface RestoreSetClickListener {
+    fun onRestoreSetClicked(set: RestoreSet)
+}

app/src/main/java/com/stevesoltys/backup/restore/RestoreViewModel.kt

@@ -0,0 +1,131 @@
+package com.stevesoltys.backup.restore
+
+import android.app.Application
+import android.app.backup.IRestoreObserver
+import android.app.backup.IRestoreSession
+import android.app.backup.RestoreSet
+import android.net.Uri
+import android.util.Log
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import com.stevesoltys.backup.Backup
+import com.stevesoltys.backup.R
+import com.stevesoltys.backup.session.backup.BackupMonitor
+import com.stevesoltys.backup.transport.TRANSPORT_ID
+import com.stevesoltys.backup.ui.BackupViewModel
+
+private val TAG = RestoreViewModel::class.java.simpleName
+
+class RestoreViewModel(app: Application) : BackupViewModel(app) {
+
+    private val backupManager = Backup.backupManager
+
+    private var session: IRestoreSession? = null
+    private var observer: RestoreObserver? = null
+    private val monitor = BackupMonitor()
+
+    private val mRestoreSets = MutableLiveData<RestoreSetResult>()
+    internal val restoreSets: LiveData<RestoreSetResult> get() = mRestoreSets
+
+    override fun acceptBackupLocation(folderUri: Uri): Boolean {
+        // TODO
+        return true
+    }
+
+    internal fun loadRestoreSets() {
+        val session = this.session ?: backupManager.beginRestoreSession(null, TRANSPORT_ID)
+        this.session = session
+
+        if (session == null) {
+            Log.e(TAG, "beginRestoreSession() returned null session")
+            mRestoreSets.value = RestoreSetResult(app.getString(R.string.restore_set_error))
+            return
+        }
+        val observer = this.observer ?: RestoreObserver()
+        this.observer = observer
+
+        val setResult = session.getAvailableRestoreSets(observer, monitor)
+        if (setResult != 0) {
+            Log.e(TAG, "getAvailableRestoreSets() returned non-zero value")
+            mRestoreSets.value = RestoreSetResult(app.getString(R.string.restore_set_error))
+            return
+        }
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+        endSession()
+    }
+
+    private fun endSession() {
+        session?.endRestoreSession()
+        session = null
+        observer = null
+    }
+
+    private inner class RestoreObserver : IRestoreObserver.Stub() {
+
+        /**
+         * Supply a list of the restore datasets available from the current transport.
+         * This method is invoked as a callback following the application's use of the
+         * [IRestoreSession.getAvailableRestoreSets] method.
+         *
+         * @param restoreSets An array of [RestoreSet] objects
+         *   describing all of the available datasets that are candidates for restoring to
+         *   the current device. If no applicable datasets exist, restoreSets will be null.
+         */
+        override fun restoreSetsAvailable(restoreSets: Array<out RestoreSet>?) {
+            if (restoreSets == null || restoreSets.isEmpty()) {
+                mRestoreSets.value = RestoreSetResult(app.getString(R.string.restore_set_empty_result))
+            } else {
+                mRestoreSets.postValue(RestoreSetResult(restoreSets))
+            }
+        }
+
+        /**
+         * The restore operation has begun.
+         *
+         * @param numPackages The total number of packages being processed in this restore operation.
+         */
+        override fun restoreStarting(numPackages: Int) {
+            Log.e(TAG, "RESTORE STARTING $numPackages")
+        }
+
+        /**
+         * An indication of which package is being restored currently,
+         * out of the total number provided in the [restoreStarting] callback.
+         * This method is not guaranteed to be called.
+         *
+         * @param nowBeingRestored The index, between 1 and the numPackages parameter
+         *   to the [restoreStarting] callback, of the package now being restored.
+         * @param currentPackage The name of the package now being restored.
+         */
+        override fun onUpdate(nowBeingRestored: Int, currentPackage: String) {
+            Log.e(TAG, "RESTORE UPDATE $nowBeingRestored $currentPackage")
+        }
+
+        /**
+         * The restore operation has completed.
+         *
+         * @param error Zero on success; a nonzero error code if the restore operation
+         *   as a whole failed.
+         */
+        override fun restoreFinished(error: Int) {
+            Log.e(TAG, "RESTORE FINISHED $error")
+            endSession()
+        }
+
+    }
+
+}
+
+internal class RestoreSetResult(
+        internal val sets: Array<out RestoreSet>,
+        internal val errorMsg: String?) {
+
+    internal constructor(sets: Array<out RestoreSet>) : this(sets, null)
+
+    internal constructor(errorMsg: String) : this(emptyArray(), errorMsg)
+
+    internal fun hasError(): Boolean = errorMsg != null
+}

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

@@ -1,85 +1,28 @@
 package com.stevesoltys.backup.settings
 
-import android.content.Intent
 import android.os.Bundle
-import android.util.Log
-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
+import com.stevesoltys.backup.ui.BackupActivity
+import com.stevesoltys.backup.ui.BackupViewModel
 
-private val TAG = SettingsActivity::class.java.name
+class SettingsActivity : BackupActivity() {
-
-const val REQUEST_CODE_OPEN_DOCUMENT_TREE = 1
-const val REQUEST_CODE_RECOVERY_CODE = 2
-
-class SettingsActivity : AppCompatActivity() {
 
     private lateinit var viewModel: SettingsViewModel
 
+    override fun getViewModel(): BackupViewModel = viewModel
+
+    override fun getInitialFragment() = SettingsFragment()
+
     override fun onCreate(savedInstanceState: Bundle?) {
+        viewModel = ViewModelProviders.of(this).get(SettingsViewModel::class.java)
         super.onCreate(savedInstanceState)
 
-        setContentView(R.layout.activity_settings)
+        setContentView(R.layout.activity_fragment_container)
-
-        viewModel = ViewModelProviders.of(this).get(SettingsViewModel::class.java)
-        viewModel.onLocationSet.observeEvent(this, LiveEventHandler { initialSetUp ->
-            if (initialSetUp) showFragment(SettingsFragment())
-            else supportFragmentManager.popBackStack()
-        })
-        viewModel.chooseBackupLocation.observeEvent(this, LiveEventHandler { show ->
-            if (show) showFragment(BackupLocationFragment(), true)
-        })
 
         supportActionBar!!.setDisplayHomeAsUpEnabled(true)
 
-        if (savedInstanceState == null) showFragment(SettingsFragment())
+        if (savedInstanceState == null) showFragment(getInitialFragment())
-    }
-
-    override fun onActivityResult(requestCode: Int, resultCode: Int, result: Intent?) {
-        if (resultCode != RESULT_OK) {
-            Log.w(TAG, "Error in activity result: $requestCode")
-            finishAfterTransition()
-        } else {
-            super.onActivityResult(requestCode, resultCode, result)
-        }
-    }
-
-    override fun onStart() {
-        super.onStart()
-        if (isFinishing) return
-
-        // check that backup is provisioned
-        if (!viewModel.recoveryCodeIsSet()) {
-            showRecoveryCodeActivity()
-        } else if (!viewModel.validLocationIsSet()) {
-            showFragment(BackupLocationFragment())
-            // remove potential error notifications
-            (application as Backup).notificationManager.onBackupErrorSeen()
-        }
-    }
-
-    override fun onOptionsItemSelected(item: MenuItem): Boolean = when {
-        item.itemId == android.R.id.home -> {
-            onBackPressed()
-            true
-        }
-        else -> super.onOptionsItemSelected(item)
-    }
-
-    private fun showRecoveryCodeActivity() {
-        val intent = Intent(this, RecoveryCodeActivity::class.java)
-        startActivityForResult(intent, REQUEST_CODE_RECOVERY_CODE)
-    }
-
-    private fun showFragment(f: Fragment, addToBackStack: Boolean = false) {
-        val fragmentTransaction = supportFragmentManager.beginTransaction()
-                .replace(R.id.fragment, f)
-        if (addToBackStack) fragmentTransaction.addToBackStack(null)
-        fragmentTransaction.commit()
     }
 
 }

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

@@ -1,6 +1,7 @@
 package com.stevesoltys.backup.settings
 
 import android.content.Context.BACKUP_SERVICE
+import android.content.Intent
 import android.os.Bundle
 import android.os.RemoteException
 import android.provider.Settings
@@ -17,6 +18,7 @@ import androidx.preference.PreferenceFragmentCompat
 import androidx.preference.TwoStatePreference
 import com.stevesoltys.backup.Backup
 import com.stevesoltys.backup.R
+import com.stevesoltys.backup.restore.RestoreActivity
 
 private val TAG = SettingsFragment::class.java.name
 
@@ -100,7 +102,7 @@ class SettingsFragment : PreferenceFragmentCompat() {
             true
         }
         item.itemId == R.id.action_restore -> {
-            Toast.makeText(requireContext(), "Not yet implemented", LENGTH_SHORT).show()
+            startActivity(Intent(requireContext(), RestoreActivity::class.java))
             true
         }
         else -> super.onOptionsItemSelected(item)

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

@@ -1,66 +1,10 @@
 package com.stevesoltys.backup.settings
 
 import android.app.Application
-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
+import com.stevesoltys.backup.ui.BackupViewModel
 
-private val TAG = SettingsViewModel::class.java.simpleName
+class SettingsViewModel(app: Application) : BackupViewModel(app) {
-
-class SettingsViewModel(application: Application) : AndroidViewModel(application) {
-
-    private val app = application
-
-    private val locationWasSet = MutableLiveEvent<Boolean>()
-    /**
-     * Will be set to true if this is the initial location.
-     * It will be false if an existing location was changed.
-     */
-    internal val onLocationSet: LiveEvent<Boolean> = locationWasSet
-
-    private val mChooseBackupLocation = MutableLiveEvent<Boolean>()
-    internal val chooseBackupLocation: LiveEvent<Boolean> = mChooseBackupLocation
-    internal fun chooseBackupLocation() = mChooseBackupLocation.setEvent(true)
-
-    fun recoveryCodeIsSet() = Backup.keyManager.hasBackupKey()
-
-    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
-
-        // persist permission to access backup folder across reboots
-        val takeFlags = result.flags and (FLAG_GRANT_READ_URI_PERMISSION or FLAG_GRANT_WRITE_URI_PERMISSION)
-        app.contentResolver.takePersistableUriPermission(folderUri, takeFlags)
-
-        // check if this is initial set-up or a later change
-        val initialSetUp = !validLocationIsSet()
-
-        // store backup folder location in settings
-        setBackupFolderUri(app, folderUri)
-
-        // notify the UI that the location has been set
-        locationWasSet.setEvent(initialSetUp)
-
-        // stop backup service to be sure the old location will get updated
-        app.stopService(Intent(app, ConfigurableBackupTransportService::class.java))
-
-        Log.d(TAG, "New storage location chosen: $folderUri")
-    }
 
     fun backupNow() = Thread { requestBackup(app) }.start()
 

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

@@ -12,6 +12,7 @@ import android.os.ParcelFileDescriptor
 import android.util.Log
 import com.stevesoltys.backup.settings.SettingsActivity
 
+val TRANSPORT_ID: String = ConfigurableBackupTransport::class.java.name
 const val DEFAULT_RESTORE_SET_TOKEN: Long = 1
 
 private const val TRANSPORT_DIRECTORY_NAME = "com.stevesoltys.backup.transport.ConfigurableBackupTransport"
@@ -32,8 +33,7 @@ class ConfigurableBackupTransport internal constructor(private val context: Cont
     }
 
     override fun name(): String {
-        // TODO: Make this class non-static in ConfigurableBackupTransportService and use Context and a ComponentName.
+        return TRANSPORT_ID
-        return this.javaClass.name
     }
 
     override fun getTransportFlags(): Int {

app/src/main/java/com/stevesoltys/backup/ui/BackupActivity.kt

@@ -0,0 +1,95 @@
+package com.stevesoltys.backup.ui
+
+import android.content.Intent
+import android.os.Bundle
+import android.util.Log
+import android.view.MenuItem
+import android.widget.Toast
+import android.widget.Toast.LENGTH_LONG
+import androidx.annotation.CallSuper
+import androidx.appcompat.app.AppCompatActivity
+import androidx.fragment.app.Fragment
+import com.stevesoltys.backup.Backup
+import com.stevesoltys.backup.R
+
+const val REQUEST_CODE_OPEN_DOCUMENT_TREE = 1
+const val REQUEST_CODE_RECOVERY_CODE = 2
+
+private val TAG = BackupActivity::class.java.name
+
+/**
+ * An Activity that requires the recovery code and the backup location to be set up
+ * before starting.
+ */
+abstract class BackupActivity : AppCompatActivity() {
+
+    protected abstract fun getViewModel(): BackupViewModel
+
+    protected abstract fun getInitialFragment(): Fragment
+
+    @CallSuper
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        getViewModel().onLocationSet.observeEvent(this, LiveEventHandler { result ->
+            if (result.validLocation) {
+                if (result.initialSetup) showFragment(getInitialFragment())
+                else supportFragmentManager.popBackStack()
+            } else onInvalidLocation()
+        })
+        getViewModel().chooseBackupLocation.observeEvent(this, LiveEventHandler { show ->
+            if (show) showFragment(BackupLocationFragment(), true)
+        })
+    }
+
+    @CallSuper
+    override fun onStart() {
+        super.onStart()
+        if (isFinishing) return
+
+        // check that backup is provisioned
+        if (!getViewModel().recoveryCodeIsSet()) {
+            showRecoveryCodeActivity()
+        } else if (!getViewModel().validLocationIsSet()) {
+            showFragment(BackupLocationFragment())
+            // remove potential error notifications
+            (application as Backup).notificationManager.onBackupErrorSeen()
+        }
+    }
+
+    @CallSuper
+    override fun onActivityResult(requestCode: Int, resultCode: Int, result: Intent?) {
+        if (resultCode != RESULT_OK) {
+            Log.w(TAG, "Error in activity result: $requestCode")
+            finishAfterTransition()
+        } else {
+            super.onActivityResult(requestCode, resultCode, result)
+        }
+    }
+
+    @CallSuper
+    override fun onOptionsItemSelected(item: MenuItem): Boolean = when {
+        item.itemId == android.R.id.home -> {
+            onBackPressed()
+            true
+        }
+        else -> super.onOptionsItemSelected(item)
+    }
+
+    private fun showRecoveryCodeActivity() {
+        val intent = Intent(this, RecoveryCodeActivity::class.java)
+        startActivityForResult(intent, REQUEST_CODE_RECOVERY_CODE)
+    }
+
+    protected open fun onInvalidLocation() {
+        Toast.makeText(this, getString(R.string.settings_backup_location_invalid), LENGTH_LONG).show()
+    }
+
+    protected fun showFragment(f: Fragment, addToBackStack: Boolean = false) {
+        val fragmentTransaction = supportFragmentManager.beginTransaction()
+                .replace(R.id.fragment, f)
+        if (addToBackStack) fragmentTransaction.addToBackStack(null)
+        fragmentTransaction.commit()
+    }
+
+}

app/src/main/java/com/stevesoltys/backup/ui/BackupLocationFragment.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.backup.settings
+package com.stevesoltys.backup.ui
 
 import android.app.Activity.RESULT_OK
 import android.content.ActivityNotFoundException
@@ -12,8 +12,7 @@ import androidx.lifecycle.ViewModelProviders
 import androidx.preference.Preference
 import androidx.preference.PreferenceFragmentCompat
 import com.stevesoltys.backup.R
-
+import com.stevesoltys.backup.settings.SettingsViewModel
-private val TAG = BackupLocationFragment::class.java.name
 
 class BackupLocationFragment : PreferenceFragmentCompat() {
 

app/src/main/java/com/stevesoltys/backup/ui/BackupViewModel.kt

@@ -0,0 +1,76 @@
+package com.stevesoltys.backup.ui
+
+import android.app.Application
+import android.content.Intent
+import android.content.Intent.FLAG_GRANT_READ_URI_PERMISSION
+import android.content.Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+import android.net.Uri
+import android.util.Log
+import androidx.documentfile.provider.DocumentFile
+import androidx.lifecycle.AndroidViewModel
+import com.stevesoltys.backup.Backup
+import com.stevesoltys.backup.isOnExternalStorage
+import com.stevesoltys.backup.settings.getBackupFolderUri
+import com.stevesoltys.backup.settings.setBackupFolderUri
+import com.stevesoltys.backup.transport.ConfigurableBackupTransportService
+
+private val TAG = BackupViewModel::class.java.simpleName
+
+abstract class BackupViewModel(protected val app: Application) : AndroidViewModel(app) {
+
+    private val locationWasSet = MutableLiveEvent<LocationResult>()
+    /**
+     * Will be set to true if this is the initial location.
+     * It will be false if an existing location was changed.
+     */
+    internal val onLocationSet: LiveEvent<LocationResult> = locationWasSet
+
+    private val mChooseBackupLocation = MutableLiveEvent<Boolean>()
+    internal val chooseBackupLocation: LiveEvent<Boolean> = mChooseBackupLocation
+    internal fun chooseBackupLocation() = mChooseBackupLocation.setEvent(true)
+
+    internal fun recoveryCodeIsSet() = Backup.keyManager.hasBackupKey()
+
+    internal 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
+    }
+
+    internal fun handleChooseFolderResult(result: Intent?) {
+        val folderUri = result?.data ?: return
+
+        // persist permission to access backup folder across reboots
+        val takeFlags = result.flags and (FLAG_GRANT_READ_URI_PERMISSION or FLAG_GRANT_WRITE_URI_PERMISSION)
+        app.contentResolver.takePersistableUriPermission(folderUri, takeFlags)
+
+        // check if this is initial set-up or a later change
+        val initialSetUp = !validLocationIsSet()
+
+        if (acceptBackupLocation(folderUri)) {
+            // store backup folder location in settings
+            setBackupFolderUri(app, folderUri)
+
+            // notify the UI that the location has been set
+            locationWasSet.setEvent(LocationResult(true, initialSetUp))
+
+            // stop backup service to be sure the old location will get updated
+            app.stopService(Intent(app, ConfigurableBackupTransportService::class.java))
+
+            Log.d(TAG, "New storage location chosen: $folderUri")
+        } else {
+            Log.w(TAG, "Location was rejected: $folderUri")
+
+            // notify the UI that the location was invalid
+            locationWasSet.setEvent(LocationResult(false, initialSetUp))
+        }
+    }
+
+    protected open fun acceptBackupLocation(folderUri: Uri): Boolean {
+        return true
+    }
+
+}
+
+class LocationResult(val validLocation: Boolean, val initialSetup: Boolean)

app/src/main/java/com/stevesoltys/backup/ui/LiveEvent.kt

@@ -1,9 +1,9 @@
-package com.stevesoltys.backup
+package com.stevesoltys.backup.ui
 
 import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
-import com.stevesoltys.backup.LiveEvent.ConsumableEvent
+import com.stevesoltys.backup.ui.LiveEvent.ConsumableEvent
 
 open class LiveEvent<T> : LiveData<ConsumableEvent<T>>() {
 

app/src/main/java/com/stevesoltys/backup/ui/LiveEventHandler.java

@@ -1,4 +1,4 @@
-package com.stevesoltys.backup;
+package com.stevesoltys.backup.ui;
 
 public interface LiveEventHandler<T> {
     void onEvent(T t);

app/src/main/java/com/stevesoltys/backup/ui/MutableLiveEvent.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.backup
+package com.stevesoltys.backup.ui
 
 class MutableLiveEvent<T> : LiveEvent<T>() {
 

app/src/main/java/com/stevesoltys/backup/ui/RecoveryCodeActivity.kt

@@ -1,10 +1,9 @@
-package com.stevesoltys.backup.settings
+package com.stevesoltys.backup.ui
 
 import android.os.Bundle
 import android.view.MenuItem
 import androidx.appcompat.app.AppCompatActivity
 import androidx.lifecycle.ViewModelProviders
-import com.stevesoltys.backup.LiveEventHandler
 import com.stevesoltys.backup.R
 
 class RecoveryCodeActivity : AppCompatActivity() {

app/src/main/java/com/stevesoltys/backup/ui/RecoveryCodeAdapter.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.backup.settings
+package com.stevesoltys.backup.ui
 
 import android.view.LayoutInflater
 import android.view.View

app/src/main/java/com/stevesoltys/backup/ui/RecoveryCodeInputFragment.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.backup.settings
+package com.stevesoltys.backup.ui
 
 import android.os.Build
 import android.os.Bundle
@@ -57,7 +57,7 @@ class RecoveryCodeInputFragment : Fragment() {
     }
 
     private fun allFilledOut(input: List<CharSequence>): Boolean {
-        for (i in 0 until input.size) {
+        for (i in input.indices) {
             if (input[i].isNotEmpty()) continue
             showError(i, getString(R.string.recovery_code_error_empty_word))
             return false
@@ -96,7 +96,7 @@ class RecoveryCodeInputFragment : Fragment() {
 
     private fun debugPreFill() {
         val words = viewModel.wordList
-        for (i in 0 until words.size) {
+        for (i in words.indices) {
             getWordLayout(i).editText!!.setText(words[i])
         }
     }

app/src/main/java/com/stevesoltys/backup/ui/RecoveryCodeOutputFragment.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.backup.settings
+package com.stevesoltys.backup.ui
 
 import android.content.res.Configuration
 import android.os.Bundle

app/src/main/java/com/stevesoltys/backup/ui/RecoveryCodeViewModel.kt

@@ -1,10 +1,8 @@
-package com.stevesoltys.backup.settings
+package com.stevesoltys.backup.ui
 
 import android.app.Application
 import androidx.lifecycle.AndroidViewModel
 import com.stevesoltys.backup.Backup
-import com.stevesoltys.backup.LiveEvent
-import com.stevesoltys.backup.MutableLiveEvent
 import io.github.novacrypto.bip39.*
 import io.github.novacrypto.bip39.Validation.InvalidChecksumException
 import io.github.novacrypto.bip39.Validation.InvalidWordCountException

app/src/main/res/drawable/ic_cloud_download.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="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M19.35,10.04C18.67,6.59 15.64,4 12,4 9.11,4 6.6,5.64 5.35,8.04 2.34,8.36 0,10.91 0,14c0,3.31 2.69,6 6,6h13c2.76,0 5,-2.24 5,-5 0,-2.64 -2.05,-4.78 -4.65,-4.96zM17,13l-5,5 -5,-5h3V9h4v4h3z" />
+</vector>

app/src/main/res/drawable/ic_phone_android.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="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M16,1L8,1C6.34,1 5,2.34 5,4v16c0,1.66 1.34,3 3,3h8c1.66,0 3,-1.34 3,-3L19,4c0,-1.66 -1.34,-3 -3,-3zM14,21h-4v-1h4v1zM17.25,18L6.75,18L6.75,4h10.5v14z" />
+</vector>

app/src/main/res/layout/fragment_recovery_code_input.xml

@@ -9,7 +9,7 @@
     <androidx.constraintlayout.widget.ConstraintLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        tools:context=".settings.RecoveryCodeInputFragment">
+        tools:context=".ui.RecoveryCodeInputFragment">
 
         <ImageView
             android:id="@+id/introIcon"

app/src/main/res/layout/fragment_restore_set.xml

@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <ImageView
+        android:id="@+id/imageView"
+        android:layout_width="32dp"
+        android:layout_height="32dp"
+        android:layout_margin="16dp"
+        android:tint="?android:colorAccent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:srcCompat="@drawable/ic_cloud_download"
+        tools:ignore="ContentDescription" />
+
+    <TextView
+        android:id="@+id/titleView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="16dp"
+        android:text="@string/restore_choose_restore_set"
+        android:textSize="24sp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/imageView" />
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/listView"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_marginStart="16dp"
+        android:layout_marginTop="16dp"
+        android:layout_marginEnd="16dp"
+        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
+        app:layout_constraintBottom_toTopOf="@+id/backView"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/titleView"
+        tools:listitem="@layout/list_item_restore_set" />
+
+    <ProgressBar
+        android:id="@+id/progressBar"
+        style="?android:progressBarStyleLarge"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        app:layout_constraintBottom_toTopOf="@+id/backView"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/titleView" />
+
+    <TextView
+        android:id="@+id/errorView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:textColor="@android:color/holo_red_dark"
+        android:textSize="18sp"
+        android:visibility="invisible"
+        app:layout_constraintBottom_toTopOf="@+id/backView"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/titleView"
+        tools:text="There was an error retrieving your backups." />
+
+    <TextView
+        android:id="@+id/backView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="16dp"
+        android:text="@string/restore_back"
+        android:textColor="?android:colorAccent"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.0"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/listView" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/list_item_restore_set.xml

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="?android:selectableItemBackground"
+    tools:showIn="@layout/fragment_restore_set">
+
+    <ImageView
+        android:id="@+id/imageView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="16dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:srcCompat="@drawable/ic_phone_android"
+        tools:ignore="ContentDescription" />
+
+    <TextView
+        android:id="@+id/titleView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="16dp"
+        android:layout_marginTop="16dp"
+        android:textColor="?android:attr/textColorSecondary"
+        android:textSize="18sp"
+        app:layout_constraintStart_toEndOf="@+id/imageView"
+        app:layout_constraintTop_toTopOf="parent"
+        tools:text="Pixel 2 XL backup" />
+
+    <TextView
+        android:id="@+id/subtitleView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="8dp"
+        android:layout_marginBottom="16dp"
+        android:textColor="?android:attr/textColorTertiary"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="@+id/titleView"
+        app:layout_constraintTop_toBottomOf="@+id/titleView"
+        tools:text="Yesterday, 8:25 AM" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -29,6 +29,7 @@
     <string name="settings_backup_location_picker">Choose backup location</string>
     <string name="settings_backup_location_title">Backup Location</string>
     <string name="settings_backup_location_info">Choose where to store your backups. More options might get added in the future.</string>
+    <string name="settings_backup_location_invalid">The chosen location can not be used.</string>
     <string name="settings_backup_external_storage">External Storage</string>
     <string name="settings_info">All backups are encrypted on your phone. To restore from backup you will need your 12-word recovery code.</string>
     <string name="settings_auto_restore_title">Automatic restore</string>
@@ -70,4 +71,11 @@
     <string name="notification_error_text">A device backup failed to run.</string>
     <string name="notification_error_action">Fix</string>
 
+    <!-- Restore -->
+    <string name="restore_title">Restore from Backup</string>
+    <string name="restore_choose_restore_set">Choose a backup to restore</string>
+    <string name="restore_back">Don\'t restore</string>
+    <string name="restore_set_error">An error occurred loading the backups.</string>
+    <string name="restore_set_empty_result">No backups found at given location.</string>
+
 </resources>

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

@@ -4,4 +4,9 @@
         <item name="preferenceTheme">@style/PreferenceThemeOverlay</item>
     </style>
 
+    <style name="AppTheme.NoActionBar" parent="AppTheme">
+        <item name="windowActionBar">false</item>
+        <item name="windowNoTitle">true</item>
+    </style>
+
 </resources>