Added support for the upload status snackbar in the event screen

lib/src/screens/event_screen.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 
-import '../utils.dart' show getImageThumbnailPath;
+import '../utils.dart' show getImageThumbnailPath, showUploadStatusSnackBar;
 import '../blocs/event_bloc.dart';
 import '../screens/gallery_screen.dart';
 import '../models/task_model.dart';
@@ -189,9 +189,16 @@ class _EventScreenState extends State<EventScreen>
     );
   }
 
+  // TODO: use a block provider instead of passing callbacks
   Future<void> onAddPicturePressed() async {
     await Navigator.of(context).pushNamed('newImage/${bloc.eventName}');
-    print('popped the pictures');
+    if (bloc.snackBarStatus.value == false) {
+      showUploadStatusSnackBar(
+        _scaffoldContext,
+        bloc.uploadStatus,
+        bloc.updateSnackBarStatus,
+      );
+    }
   }
 
   void dispose() {

lib/src/screens/new_image_screen.dart

@@ -154,7 +154,7 @@ class _NewImageScreenState extends State<NewImageScreen> {
 
   /// Saves the image to the storage bucket.
   void onSubmit() async {
-    await bloc.submit();
+    bloc.submit();
     Navigator.of(context).pop();
   }
 

lib/src/services/upload_status_service.dart

@@ -28,12 +28,8 @@ class UploadStatusService {
   ///
   /// The task gets automatically removed when done.
   void addNewUpload(StorageUploadTask task) async {
-    final initialSnap = task.lastSnapshot;
-    // Initialize the map entry with the initial values.
-    _tasksData[task] = [
-      initialSnap.bytesTransferred,
-      initialSnap.totalByteCount,
-    ];
+    // Initialize the map entry with initial values.
+    _tasksData[task] = [0, 0];
     task.events.listen(
       (StorageTaskEvent event) {
         // Update the map with the current values.
@@ -47,6 +43,7 @@ class UploadStatusService {
     );
     await task.onComplete;
     _tasksData.remove(task);
+    _sendUpdate();
   }
 
   /// Updates the _status subject with the most current data.
@@ -60,10 +57,10 @@ class UploadStatusService {
       },
     );
     if (bytestTransferred != 0) {
-      percentage = totalBytes / bytestTransferred;
+      percentage = bytestTransferred / totalBytes;
     }
     _status.sink.add(UploadStatus(
-      percentage: percentage,
+      percentage: (percentage * 100).toStringAsFixed(2),
       numberOfFiles: _tasksData.length,
     ));
   }
@@ -77,7 +74,7 @@ class UploadStatusService {
 /// The status of an upload.
 class UploadStatus {
   /// Percentage of the upload.
-  final double percentage;
+  final String percentage;
 
   /// Number of files being uploaded.
   ///

lib/src/utils.dart

@@ -71,9 +71,46 @@ String getImageThumbnailPath(String path) {
   return tokens.join('/');
 }
 
+/// Shows an upload status snack bar.
 ///
+/// Takes the data from the [uploadStatus] stream and shows in the snack bar.
+/// Calls [onSuccessfullyClosed] with [false] when all files are done being
+/// uploaded.
 void showUploadStatusSnackBar(
-  BuildContext context,
+  BuildContext scaffoldContext,
   Observable<UploadStatus> uploadStatus,
-  ValueObservable<bool> snackBarStatus,
-) {}
+  Function(bool) onSuccessfullyClosed,
+) {
+  assert(scaffoldContext != null);
+  assert(uploadStatus != null);
+  assert(onSuccessfullyClosed != null);
+  final scaffoldState = Scaffold.of(scaffoldContext);
+  scaffoldState.showSnackBar(SnackBar(
+    /// The snack bar shouldn't close until the files are done uploading
+    /// hence the long duration. It gets closed programatically.
+    duration: Duration(hours: 1),
+    content: StreamBuilder(
+      stream: uploadStatus,
+      builder: (BuildContext context, AsyncSnapshot<UploadStatus> snap) {
+        if (!snap.hasData) {
+          return Text('');
+        }
+        print('Number of files: ${snap.data.numberOfFiles}');
+        if (snap.data.numberOfFiles == 0) {
+          onSuccessfullyClosed(false);
+          scaffoldState.hideCurrentSnackBar();
+          return Text('');
+        }
+        return Row(
+          children: <Widget>[
+            Spacer(),
+            Text('${snap.data.numberOfFiles} pending files'),
+            Spacer(flex: 5),
+            Text(snap.data.percentage + '%'),
+            Spacer(),
+          ],
+        );
+      },
+    ),
+  ));
+}