From 085f5d7d6846ba132d7897faa770bc397ef828e0 Mon Sep 17 00:00:00 2001
From: MohammadTaha Basiri <m.taha.basiri@gmail.com>
Date: Fri, 4 Mar 2022 11:52:41 +0330
Subject: [PATCH] D1APP-108 interactive viewer back button style

---
 lib/views/widgets/didvan/page_view.dart | 29 ++++++++++++-------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/lib/views/widgets/didvan/page_view.dart b/lib/views/widgets/didvan/page_view.dart
index e42744c..7faf24f 100644
--- a/lib/views/widgets/didvan/page_view.dart
+++ b/lib/views/widgets/didvan/page_view.dart
@@ -8,7 +8,6 @@ import 'package:didvan/views/home/widgets/tag_item.dart';
 import 'package:didvan/views/widgets/animated_visibility.dart';
 import 'package:didvan/views/widgets/didvan/card.dart';
 import 'package:didvan/views/widgets/didvan/divider.dart';
-import 'package:didvan/views/widgets/didvan/icon_button.dart';
 import 'package:didvan/views/widgets/didvan/text.dart';
 import 'package:didvan/views/widgets/ink_wrapper.dart';
 import 'package:didvan/views/widgets/item_title.dart';
@@ -194,7 +193,6 @@ class _DidvanPageViewState extends State<DidvanPageView> {
           'span': Style(
             textAlign: TextAlign.center,
             fontSize: FontSize.small,
-            alignment: Alignment.center,
           ),
         },
       );
@@ -219,11 +217,7 @@ class _DidvanPageViewState extends State<DidvanPageView> {
                 ),
                 Positioned(
                   right: 16,
-                  child: DidvanIconButton(
-                    backgroundColor: Theme.of(context).colorScheme.primary,
-                    icon: DidvanIcons.back_regular,
-                    onPressed: Navigator.of(context).pop,
-                  ),
+                  child: _BackButton(),
                 ),
               ],
             ),
@@ -277,9 +271,8 @@ class _DidvanPageViewState extends State<DidvanPageView> {
 }
 
 class _BackButton extends StatefulWidget {
-  final ScrollController scrollController;
-  const _BackButton({Key? key, required this.scrollController})
-      : super(key: key);
+  final ScrollController? scrollController;
+  const _BackButton({Key? key, this.scrollController}) : super(key: key);
 
   @override
   __BackButtonState createState() => __BackButtonState();
@@ -290,20 +283,26 @@ class __BackButtonState extends State<_BackButton> {
 
   @override
   void didUpdateWidget(covariant _BackButton oldWidget) {
-    _isVisible = false;
-    _handleScroll();
+    if (widget.scrollController != null) {
+      _isVisible = false;
+      _handleScroll();
+    }
     super.didUpdateWidget(oldWidget);
   }
 
   @override
   void initState() {
-    _handleScroll();
+    if (widget.scrollController != null) {
+      _handleScroll();
+    } else {
+      _isVisible = true;
+    }
     super.initState();
   }
 
   void _handleScroll() {
-    widget.scrollController.addListener(() {
-      final position = widget.scrollController.position.pixels;
+    widget.scrollController!.addListener(() {
+      final position = widget.scrollController!.position.pixels;
       final size = MediaQuery.of(context).size.height * 0.3;
       if (position > size && _isVisible == false) {
         setState(() {