[mob][photos] Animate visibility toggling of appbar and bottom bar when toggling swipe lock

mobile/lib/ui/viewer/file/file_app_bar.dart

@@ -118,21 +118,27 @@ class FileAppBarState extends State<FileAppBar> {
               stops: const [0, 0.2, 1],
             ),
           ),
-          child: AppBar(
-            iconTheme: const IconThemeData(
-              color: Colors.white,
-            ), //same for both themes
-            leading: IconButton(
-              icon: const Icon(Icons.arrow_back),
-              onPressed: () {
-                _isFileSwipeLocked
-                    ? _requestAuthentication()
-                    : Navigator.of(context).pop();
-              },
+          child: AnimatedSwitcher(
+            duration: const Duration(milliseconds: 250),
+            switchInCurve: Curves.easeInOut,
+            switchOutCurve: Curves.easeInOut,
+            child: AppBar(
+              key: ValueKey(_isFileSwipeLocked),
+              iconTheme: const IconThemeData(
+                color: Colors.white,
+              ), //same for both themes
+              leading: IconButton(
+                icon: const Icon(Icons.arrow_back),
+                onPressed: () {
+                  _isFileSwipeLocked
+                      ? _requestAuthentication()
+                      : Navigator.of(context).pop();
+                },
+              ),
+              actions: shouldShowActions && !_isFileSwipeLocked ? _actions : [],
+              elevation: 0,
+              backgroundColor: const Color(0x00000000),
             ),
-            actions: shouldShowActions && !_isFileSwipeLocked ? _actions : [],
-            elevation: 0,
-            backgroundColor: const Color(0x00000000),
           ),
         ),
       ),

mobile/lib/ui/viewer/file/file_bottom_bar.dart

@@ -38,8 +38,8 @@ class FileBottomBar extends StatefulWidget {
     required this.onFileRemoved,
     required this.enableFullScreenNotifier,
     this.userID,
-    Key? key,
-  }) : super(key: key);
+    super.key,
+  });
 
   @override
   FileBottomBarState createState() => FileBottomBarState();
@@ -76,7 +76,7 @@ class FileBottomBarState extends State<FileBottomBar> {
       isPanorama = widget.file.isPanorama() ?? false;
       _checkPanorama();
     }
-    return _isFileSwipeLocked ? Container() : _getBottomBar();
+    return _getBottomBar();
   }
 
   // _checkPanorama() method is used to check if the file is a panorama image.
@@ -222,8 +222,9 @@ class FileBottomBarState extends State<FileBottomBar> {
         return IgnorePointer(
           ignoring: isFullScreen || _isFileSwipeLocked,
           child: AnimatedOpacity(
-            opacity: isFullScreen ? 0 : 1,
-            duration: const Duration(milliseconds: 150),
+            opacity: isFullScreen || _isFileSwipeLocked ? 0 : 1,
+            duration: const Duration(milliseconds: 250),
+            curve: Curves.easeInOut,
             child: Align(
               alignment: Alignment.bottomCenter,
               child: Container(