Adds Adds FilePickerStatus event handler to FilePickerPlatform

file_picker_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## [1.2.0] - Adds FilePickerStatus
+
+Adds `onFiledLoading` that will provide an event handler with `FilePickerStatus` when picking files.
+
 ## [1.1.0] - Adds directory pick 
 
 Implements `getDirectoryPath()`

file_picker_platform_interface/lib/file_picker_platform_interface.dart

@@ -11,6 +11,11 @@ enum FileType {
   custom,
 }
 
+enum FilePickerStatus {
+  picking,
+  done,
+}
+
 /// The interface that implementations of file_picker must implement.
 ///
 /// Platform implementations should extend this class rather than implement it as `file_picker`
@@ -38,6 +43,10 @@ abstract class FilePickerPlatform extends PlatformInterface {
   /// Default [type] set to `FileType.any` with [allowMultiple] set to `false`
   /// Optionally, [allowedExtensions] might be provided (e.g. [`pdf`, `svg`, `jpg`].).
   ///
+  /// If you want to track picking status, for example, because some files may take some time to be
+  /// cached (particularly those picked from cloud providers), you may want to set [onFileLoading] handler
+  /// that will give you the current status of picking.
+  ///
   /// Allows `dynamic` return as files may be resolved to different types, based
   /// on each platform implementation. For example, when using _dart:html_ with Flutter Web
   /// or _dart:io_ with Flutter, different `File` instances could be used.
@@ -45,6 +54,7 @@ abstract class FilePickerPlatform extends PlatformInterface {
     FileType type = FileType.any,
     List<String> allowedExtensions,
     bool allowMultiple = false,
+    Function(FilePickerStatus) onFileLoading,
   }) async =>
       throw UnimplementedError('getFiles() has not been implemented.');
 
@@ -55,11 +65,13 @@ abstract class FilePickerPlatform extends PlatformInterface {
   /// of it whenever needed. However, this will force the cleanup if you want to manage those on your own.
   ///
   /// Returns `true` if the files were removed with success, `false` otherwise.
-  Future<bool> clearTemporaryFiles() async => throw UnimplementedError('clearTemporaryFiles() has not been implemented.');
+  Future<bool> clearTemporaryFiles() async => throw UnimplementedError(
+      'clearTemporaryFiles() has not been implemented.');
 
   /// Selects a directory and returns its absolute path.
   ///
   /// On Android, this requires to be running on SDK 21 or above, else won't work.
   /// Returns `null` if folder path couldn't be resolved.
-  Future<String> getDirectoryPath() async => throw UnimplementedError('getDirectoryPath() has not been implemented.');
+  Future<String> getDirectoryPath() async =>
+      throw UnimplementedError('getDirectoryPath() has not been implemented.');
 }

file_picker_platform_interface/lib/method_channel_file_picker.dart

@@ -1,24 +1,32 @@
+import 'dart:async';
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 import 'file_picker_platform_interface.dart';
 
-const MethodChannel _channel = MethodChannel('miguelruivo.flutter.plugins.filepicker');
+const MethodChannel _channel =
+    MethodChannel('miguelruivo.flutter.plugins.filepicker');
+const EventChannel _eventChannel =
+    EventChannel('miguelruivo.flutter.plugins.filepickerevent');
 
 /// An implementation of [FilePickerPlatform] that uses method channels.
 class MethodChannelFilePicker extends FilePickerPlatform {
   static const String _tag = 'MethodChannelFilePicker';
+  static StreamSubscription _eventSubscription;
 
   @override
   Future getFiles({
     FileType type = FileType.any,
     List<String> allowedExtensions,
     bool allowMultiple = false,
+    Function(FilePickerStatus) onFileLoading,
   }) =>
-      _getPath(type, allowMultiple, allowedExtensions);
+      _getPath(type, allowMultiple, allowedExtensions, onFileLoading);
 
   @override
-  Future<bool> clearTemporaryFiles() async => _channel.invokeMethod<bool>('clear');
+  Future<bool> clearTemporaryFiles() async =>
+      _channel.invokeMethod<bool>('clear');
 
   @override
   Future<String> getDirectoryPath() async {
@@ -37,12 +45,24 @@ class MethodChannelFilePicker extends FilePickerPlatform {
     FileType fileType,
     bool allowMultipleSelection,
     List<String> allowedExtensions,
+    Function(FilePickerStatus) onFileLoading,
   ) async {
     final String type = describeEnum(fileType);
     if (type != 'custom' && (allowedExtensions?.isNotEmpty ?? false)) {
-      throw Exception('If you are using a custom extension filter, please use the FileType.custom instead.');
+      throw Exception(
+          'If you are using a custom extension filter, please use the FileType.custom instead.');
     }
     try {
+      _eventSubscription?.cancel();
+      if (onFileLoading != null) {
+        _eventSubscription = _eventChannel.receiveBroadcastStream().listen(
+              (data) => onFileLoading((data as bool)
+                  ? FilePickerStatus.picking
+                  : FilePickerStatus.done),
+              onError: (error) => throw Exception(error),
+            );
+      }
+
       dynamic result = await _channel.invokeMethod(type, {
         'allowMultipleSelection': allowMultipleSelection,
         'allowedExtensions': allowedExtensions,
@@ -51,14 +71,16 @@ class MethodChannelFilePicker extends FilePickerPlatform {
         if (result is String) {
           result = [result];
         }
-        return Map<String, String>.fromIterable(result, key: (path) => path.split('/').last, value: (path) => path);
+        return Map<String, String>.fromIterable(result,
+            key: (path) => path.split('/').last, value: (path) => path);
       }
       return result;
     } on PlatformException catch (e) {
       print('[$_tag] Platform exception: $e');
       rethrow;
     } catch (e) {
-      print('[$_tag] Unsupported operation. Method not found. The exception thrown was: $e');
+      print(
+          '[$_tag] Unsupported operation. Method not found. The exception thrown was: $e');
       rethrow;
     }
   }

file_picker_platform_interface/pubspec.yaml

@@ -1,7 +1,7 @@
 name: file_picker_platform_interface
 description: A common platform interface for the file_picker plugin
 homepage: https://github.com/miguelpruivo/plugins_flutter_file_picker/file_picker_platform_interface
-version: 1.1.0
+version: 1.2.0
 
 environment:
   sdk: ">=2.1.0 <3.0.0"