From 51d79fdbf232a4bedac53dc0fbd842d4eec20bff Mon Sep 17 00:00:00 2001
From: Vishesh Handa <me@vhanda.in>
Date: Thu, 9 Jul 2020 12:50:24 +0200
Subject: [PATCH] PurchaseScreen: Fix scrolling

Putting a column inside a SingleChildScrollView is way way too complex.
There are lots of different solutions, and not all seem to work for me.

Also adjust the loading screen.
---
 lib/screens/purchase_screen.dart | 45 ++++++++++-----------------
 lib/widgets/purchase_widget.dart | 53 ++------------------------------
 2 files changed, 19 insertions(+), 79 deletions(-)

diff --git a/lib/screens/purchase_screen.dart b/lib/screens/purchase_screen.dart
index 98bb67fb..6f801f3a 100644
--- a/lib/screens/purchase_screen.dart
+++ b/lib/screens/purchase_screen.dart
@@ -1,6 +1,5 @@
 import 'dart:async';
 import 'dart:io';
-import 'dart:math';
 
 import 'package:flutter/material.dart';
 
@@ -48,6 +47,7 @@ class PurchaseScreen extends StatelessWidget {
     var body = Column(
       mainAxisAlignment: MainAxisAlignment.center,
       crossAxisAlignment: CrossAxisAlignment.start,
+      mainAxisSize: MainAxisSize.min,
       children: <Widget>[
         Text(
           'Support GitJournal by going Pro and additionally get -',
@@ -77,10 +77,13 @@ class PurchaseScreen extends StatelessWidget {
           style: titleStyle,
           textAlign: TextAlign.center,
         ),
+        const SizedBox(height: 32.0),
         body,
+        const SizedBox(height: 32.0),
         PurchaseWidget(),
       ],
-      mainAxisAlignment: MainAxisAlignment.spaceAround,
+      mainAxisAlignment: MainAxisAlignment.start,
+      mainAxisSize: MainAxisSize.min,
     );
 
     if (Platform.isIOS) {
@@ -99,10 +102,17 @@ class PurchaseScreen extends StatelessWidget {
       );
     }
 
-    return _SingleChildScrollViewExpanded(
-      child: SafeArea(child: w),
-      padding: const EdgeInsets.all(16.0),
-    );
+    w = Padding(padding: const EdgeInsets.all(16.0), child: w);
+
+    return SafeArea(
+        child: CustomScrollView(
+      slivers: [
+        SliverFillRemaining(
+          hasScrollBody: false,
+          child: w,
+        ),
+      ],
+    ));
   }
 
   Future<bool> _onWillPop() async {
@@ -122,26 +132,3 @@ class EmptyAppBar extends StatelessWidget implements PreferredSizeWidget {
   @override
   Size get preferredSize => const Size(0.0, 0.0);
 }
-
-class _SingleChildScrollViewExpanded extends StatelessWidget {
-  final Widget child;
-  final EdgeInsetsGeometry padding;
-
-  _SingleChildScrollViewExpanded({this.child, this.padding});
-
-  @override
-  Widget build(BuildContext context) {
-    return LayoutBuilder(
-      builder: (BuildContext context, BoxConstraints constraints) {
-        return SingleChildScrollView(
-          child: ConstrainedBox(
-            constraints: BoxConstraints.tightFor(
-                height: max(100, constraints.maxHeight)),
-            child: child,
-          ),
-          padding: padding,
-        );
-      },
-    );
-  }
-}
diff --git a/lib/widgets/purchase_widget.dart b/lib/widgets/purchase_widget.dart
index 8657c14a..c8f5ad71 100644
--- a/lib/widgets/purchase_widget.dart
+++ b/lib/widgets/purchase_widget.dart
@@ -77,55 +77,6 @@ class PurchaseButton extends StatelessWidget {
   }
 }
 
-class LoadingWidget extends StatelessWidget {
-  const LoadingWidget({Key key}) : super(key: key);
-
-  @override
-  Widget build(BuildContext context) {
-    var theme = Theme.of(context);
-    var children = <Widget>[
-      Padding(
-        padding: const EdgeInsets.all(8.0),
-        child: Text(
-          "Loading",
-          textAlign: TextAlign.center,
-          style: Theme.of(context).textTheme.headline4,
-        ),
-      ),
-      const SizedBox(height: 8.0),
-      const Padding(
-        padding: EdgeInsets.all(8.0),
-        child: CircularProgressIndicator(
-          value: null,
-        ),
-      ),
-    ];
-
-    var w = Column(
-      mainAxisAlignment: MainAxisAlignment.center,
-      crossAxisAlignment: CrossAxisAlignment.center,
-      children: children,
-    );
-
-    return WillPopScope(
-      onWillPop: _onWillPopLoading,
-      child: Container(
-        child: w,
-        color: theme.scaffoldBackgroundColor,
-        padding: const EdgeInsets.all(16.0),
-        constraints: const BoxConstraints.expand(),
-      ),
-    );
-  }
-
-  Future<bool> _onWillPopLoading() async {
-    getAnalytics().logEvent(
-      name: "purchase_screen_close_loading",
-    );
-    return true;
-  }
-}
-
 class PurchaseWidget extends StatefulWidget {
   @override
   _PurchaseWidgetState createState() => _PurchaseWidgetState();
@@ -207,7 +158,9 @@ class _PurchaseWidgetState extends State<PurchaseWidget> {
 
   @override
   Widget build(BuildContext context) {
-    return _offerings == null ? const LoadingWidget() : buildBody(context);
+    return _offerings == null
+        ? const CircularProgressIndicator()
+        : buildBody(context);
   }
 
   Widget buildBody(BuildContext context) {