remove MediumType attribute in MediaPage, and remove MediumType parameter in listMedia method

lib/photo_gallery.dart

@@ -35,7 +35,6 @@ class PhotoGallery {
 
   static Future<MediaPage> _listMedia({
     @required Album album,
-    @required MediumType mediumType,
     @required int total,
     int skip,
     int take,
@@ -43,12 +42,12 @@ class PhotoGallery {
     assert(album.id != null);
     final json = await _channel.invokeMethod('listMedia', {
       'albumId': album.id,
-      'mediumType': mediumTypeToJson(mediumType),
+      'mediumType': mediumTypeToJson(album.mediumType),
       'total': total,
       'skip': skip,
       'take': take,
     });
-    return MediaPage.fromJson(album, mediumType, json);
+    return MediaPage.fromJson(album, json);
   }
 
   static Future<Medium> getMedium({

lib/src/models/album.dart

@@ -35,7 +35,6 @@ class Album {
   }) {
     return PhotoGallery._listMedia(
       album: this,
-      mediumType: this.mediumType,
       total: this.count,
       skip: skip,
       take: take,

lib/src/models/media_page.dart

@@ -5,9 +5,6 @@ part of photogallery;
 class MediaPage {
   final Album album;
 
-  /// The medium type of [items].
-  final MediumType mediumType;
-
   /// The start offset for those media.
   final int start;
 
@@ -24,7 +21,7 @@ class MediaPage {
   bool get isLast => end >= total;
 
   /// Creates a range of media from platform channel protocol.
-  MediaPage.fromJson(this.album, this.mediumType, dynamic json)
+  MediaPage.fromJson(this.album, dynamic json)
       : start = json['start'],
         total = json['total'],
         items = json['items'].map<Medium>((x) => Medium.fromJson(x)).toList();
@@ -34,7 +31,6 @@ class MediaPage {
     assert(!isLast);
     return PhotoGallery._listMedia(
       album: album,
-      mediumType: mediumType,
       total: total,
       skip: end,
       take: items.length,
@@ -47,23 +43,17 @@ class MediaPage {
       other is MediaPage &&
           runtimeType == other.runtimeType &&
           album == other.album &&
-          mediumType == other.mediumType &&
           start == other.start &&
           total == other.total &&
           listEquals(items, other.items);
 
   @override
   int get hashCode =>
-      album.hashCode ^
-      mediumType.hashCode ^
-      start.hashCode ^
-      total.hashCode ^
-      items.hashCode;
+      album.hashCode ^ start.hashCode ^ total.hashCode ^ items.hashCode;
 
   @override
   String toString() {
     return 'MediaPage{album: $album, '
-        'mediumType: $mediumType, '
         'start: $start, '
         'total: $total, '
         'items: $items}';