refactor: Make layouts null safe

lib/widgets/layouts/empty_page.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'dart:math';
 
 import 'package:flutter/material.dart';
@@ -5,7 +7,7 @@ import 'package:flutter/material.dart';
 class EmptyPage extends StatelessWidget {
   final bool loading;
   static const double _width = 200;
-  const EmptyPage({this.loading = false, Key key}) : super(key: key);
+  const EmptyPage({this.loading = false, Key? key}) : super(key: key);
   @override
   Widget build(BuildContext context) {
     final _width = min(MediaQuery.of(context).size.width, EmptyPage._width);

lib/widgets/layouts/loading_view.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'package:flutter/material.dart';
 
 import 'package:matrix/matrix.dart';
@@ -7,26 +9,21 @@ import 'package:fluffychat/widgets/layouts/empty_page.dart';
 import 'package:fluffychat/widgets/matrix.dart';
 
 class LoadingView extends StatelessWidget {
-  const LoadingView({Key key}) : super(key: key);
+  const LoadingView({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
-    if (Matrix.of(context)
+    WidgetsBinding.instance?.addPostFrameCallback(
-        .widget
+      (_) => VRouter.of(context).to(
-        .clients
+        Matrix.of(context)
-        .every((client) => client.loginState != null)) {
+                .widget
-      WidgetsBinding.instance.addPostFrameCallback(
+                .clients
-        (_) => VRouter.of(context).to(
+                .any((client) => client.loginState == LoginState.loggedIn)
-          Matrix.of(context)
+            ? '/rooms'
-                  .widget
+            : '/home',
-                  .clients
+        queryParameters: VRouter.of(context).queryParameters,
-                  .any((client) => client.loginState == LoginState.loggedIn)
+      ),
-              ? '/rooms'
+    );
-              : '/home',
-          queryParameters: VRouter.of(context).queryParameters,
-        ),
-      );
-    }
     return const EmptyPage(loading: true);
   }
 }

lib/widgets/layouts/max_width_body.dart

@@ -1,9 +1,11 @@
+//@dart=2.12
+
 import 'dart:math';
 
 import 'package:flutter/material.dart';
 
 class MaxWidthBody extends StatelessWidget {
-  final Widget child;
+  final Widget? child;
   final double maxWidth;
   final bool withScrolling;
 
@@ -11,7 +13,7 @@ class MaxWidthBody extends StatelessWidget {
     this.child,
     this.maxWidth = 600,
     this.withScrolling = false,
-    Key key,
+    Key? key,
   }) : super(key: key);
   @override
   Widget build(BuildContext context) {

lib/widgets/layouts/one_page_card.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'dart:math';
 
 import 'package:flutter/material.dart';
@@ -8,14 +10,14 @@ import 'package:fluffychat/widgets/matrix.dart';
 class OnePageCard extends StatelessWidget {
   final Widget child;
 
-  const OnePageCard({Key key, this.child}) : super(key: key);
+  const OnePageCard({Key? key, required this.child}) : super(key: key);
 
   static const int alpha = 12;
   static num breakpoint = FluffyThemes.columnWidth * 2;
   @override
   Widget build(BuildContext context) {
     final horizontalPadding =
-        max((MediaQuery.of(context).size.width - 600) / 2, 24);
+        max<double>((MediaQuery.of(context).size.width - 600) / 2, 24);
     return MediaQuery.of(context).size.width <= breakpoint ||
             Matrix.of(context).client.isLogged()
         ? child

lib/widgets/layouts/side_view_layout.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'package:flutter/material.dart';
 
 import 'package:vrouter/vrouter.dart';
@@ -6,15 +8,16 @@ import 'package:fluffychat/config/themes.dart';
 
 class SideViewLayout extends StatelessWidget {
   final Widget mainView;
-  final Widget sideView;
+  final Widget? sideView;
 
-  const SideViewLayout({Key key, @required this.mainView, this.sideView})
+  const SideViewLayout({Key? key, required this.mainView, this.sideView})
       : super(key: key);
   @override
   Widget build(BuildContext context) {
     var currentUrl = Uri.decodeFull(VRouter.of(context).url);
     if (!currentUrl.endsWith('/')) currentUrl += '/';
     final hideSideView = currentUrl.split('/').length == 4;
+    final sideView = this.sideView;
     return sideView == null
         ? mainView
         : MediaQuery.of(context).size.width < FluffyThemes.columnWidth * 3.5 &&

lib/widgets/layouts/two_column_layout.dart

@@ -1,3 +1,4 @@
+//@dart=2.12
 import 'package:flutter/material.dart';
 
 import 'package:fluffychat/config/themes.dart';
@@ -6,9 +7,11 @@ class TwoColumnLayout extends StatelessWidget {
   final Widget mainView;
   final Widget sideView;
 
-  const TwoColumnLayout(
+  const TwoColumnLayout({
-      {Key key, @required this.mainView, @required this.sideView})
+    Key? key,
-      : super(key: key);
+    required this.mainView,
+    required this.sideView,
+  }) : super(key: key);
   @override
   Widget build(BuildContext context) {
     if (MediaQuery.of(context).size.width <= FluffyThemes.columnWidth * 2) {