fix: alignment issue in login page (#3399)

frontend/appflowy_flutter/lib/user/presentation/screens/sign_in_screen/mobile_sign_in_screen.dart

@@ -11,7 +11,7 @@ class MobileSignInScreen extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    const spacing = 16;
+    const double spacing = 16;
     // Welcome to Appflowy
     final welcomeString = LocaleKeys.welcomeText.tr();
     final style = Theme.of(context);
@@ -24,7 +24,7 @@ class MobileSignInScreen extends StatelessWidget {
                 mainAxisAlignment: MainAxisAlignment.center,
                 children: [
                   Text('Signing in...'),
-                  VSpace(8),
+                  VSpace(spacing),
                   CircularProgressIndicator(),
                 ],
               ),
@@ -54,7 +54,7 @@ class MobileSignInScreen extends StatelessWidget {
                     style: style.textTheme.displayLarge,
                     textAlign: TextAlign.center,
                   ),
-                  const VSpace(16),
+                  const VSpace(spacing),
                   // TODO(yijing): confirm the subtitle before release app
                   Text(
                     'You are in charge of your data and customizations.',
@@ -65,7 +65,7 @@ class MobileSignInScreen extends StatelessWidget {
                     flex: 2,
                   ),
                   const SignInAnonymousButton(),
-                  const VSpace(16),
+                  const VSpace(spacing),
                   Row(
                     mainAxisAlignment: MainAxisAlignment.center,
                     children: [
@@ -80,9 +80,9 @@ class MobileSignInScreen extends StatelessWidget {
                       const Expanded(child: Divider()),
                     ],
                   ),
-                  const VSpace(16),
+                  const VSpace(spacing),
                   const ThirdPartySignInButtons(),
-                  const VSpace(16),
+                  const VSpace(spacing),
                 ],
               ),
             ),

frontend/appflowy_flutter/lib/user/presentation/screens/sign_in_screen/widgets/third_party_sign_in_buttons.dart

@@ -4,6 +4,7 @@ import 'package:appflowy/generated/flowy_svgs.g.dart';
 import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/startup/startup.dart';
 import 'package:appflowy/user/application/sign_in_bloc.dart';
+import 'package:appflowy/user/presentation/presentation.dart';
 import 'package:appflowy/util/platform_extension.dart';
 import 'package:appflowy/workspace/application/appearance.dart';
 import 'package:easy_localization/easy_localization.dart';
@@ -13,73 +14,31 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 class ThirdPartySignInButtons extends StatelessWidget {
-  /// Used in DesktopSignInScreen and MobileSignInScreen
+  /// Used in DesktopSignInScreen, MobileSignInScreen and SettingThirdPartyLogin
   const ThirdPartySignInButtons({
     super.key,
   });
 
   @override
   Widget build(BuildContext context) {
-    final isMobile = PlatformExtension.isMobile;
-
     // Get themeMode from AppearanceSettingsCubit
     // When user changes themeMode, it changes the state in AppearanceSettingsCubit, but the themeMode for the MaterialApp won't change, it only got updated(get value from AppearanceSettingsCubit) when user open the app again. Thus, we should get themeMode from AppearanceSettingsCubit rather than MediaQuery.
     final isDarkMode =
         context.read<AppearanceSettingsCubit>().state.themeMode ==
             ThemeMode.dark;
 
-    if (isMobile) {
-      // ThirdPartySignInButtons in mobile
-      return Column(
-        children: [
-          _ThirdPartySignInButton(
-            isMobile: true,
-            icon: FlowySvgs.google_mark_xl,
-            labelText: LocaleKeys.signIn_LogInWithGoogle.tr(),
-            onPressed: () {
-              _signInWithGoogle(context);
-            },
-          ),
-          const SizedBox(height: 8),
-          _ThirdPartySignInButton(
-            isMobile: true,
-            icon: isDarkMode
-                ? FlowySvgs.github_mark_white_xl
-                : FlowySvgs.github_mark_black_xl,
-            labelText: LocaleKeys.signIn_LogInWithGithub.tr(),
-            onPressed: () {
-              _signInWithGithub(context);
-            },
-          ),
-          const SizedBox(height: 8),
-          _ThirdPartySignInButton(
-            isMobile: true,
-            icon: isDarkMode
-                ? FlowySvgs.discord_mark_white_xl
-                : FlowySvgs.discord_mark_blurple_xl,
-            labelText: LocaleKeys.signIn_LogInWithDiscord.tr(),
-            onPressed: () {
-              _signInWithDiscord(context);
-            },
-          ),
-        ],
-      );
-    }
-    // ThirdPartySignInButtons in desktop
     return Column(
       children: [
         _ThirdPartySignInButton(
           key: const Key('signInWithGoogleButton'),
-          isMobile: false,
           icon: FlowySvgs.google_mark_xl,
           labelText: LocaleKeys.signIn_LogInWithGoogle.tr(),
           onPressed: () {
             _signInWithGoogle(context);
           },
         ),
-        const SizedBox(height: 8),
+        const VSpace(8),
         _ThirdPartySignInButton(
-          isMobile: false,
           icon: isDarkMode
               ? FlowySvgs.github_mark_white_xl
               : FlowySvgs.github_mark_black_xl,
@@ -88,9 +47,8 @@ class ThirdPartySignInButtons extends StatelessWidget {
             _signInWithGithub(context);
           },
         ),
-        const SizedBox(height: 8),
+        const VSpace(8),
         _ThirdPartySignInButton(
-          isMobile: false,
           icon: isDarkMode
               ? FlowySvgs.discord_mark_white_xl
               : FlowySvgs.discord_mark_blurple_xl,
@@ -105,15 +63,14 @@ class ThirdPartySignInButtons extends StatelessWidget {
 }
 
 class _ThirdPartySignInButton extends StatelessWidget {
+  /// Build button based on current Platform(mobile or desktop).
   const _ThirdPartySignInButton({
     super.key,
-    required this.isMobile,
     required this.icon,
     required this.labelText,
     required this.onPressed,
   });
 
-  final bool isMobile;
   final FlowySvgData icon;
   final String labelText;
 
@@ -122,39 +79,44 @@ class _ThirdPartySignInButton extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final style = Theme.of(context);
-    final buttonSize = MediaQuery.of(context).size;
+    final isMobile = PlatformExtension.isMobile;
     if (isMobile) {
-      return SizedBox(
-        width: double.infinity,
-        height: 48,
-        child: OutlinedButton.icon(
-          icon: Container(
-            width: buttonSize.width / 5.5,
-            alignment: Alignment.centerRight,
-            child: SizedBox(
-              width: 24,
-              child: FlowySvg(
-                icon,
-                blendMode: null,
+      // Use LayoutBuilder to get the maxWidth of parent widget(Column) and set the icon occupied area to 1/4 of maxWidth.
+      return LayoutBuilder(
+        builder: (context, constraints) {
+          return SizedBox(
+            height: 48,
+            child: OutlinedButton.icon(
+              icon: Container(
+                width: constraints.maxWidth / 4,
+                alignment: Alignment.centerRight,
+                child: SizedBox(
+                  width: 24,
+                  child: FlowySvg(
+                    icon,
+                    blendMode: null,
+                  ),
+                ),
               ),
+              label: Container(
+                padding: const EdgeInsets.only(left: 4),
+                alignment: Alignment.centerLeft,
+                child: Text(labelText),
+              ),
+              onPressed: onPressed,
             ),
-          ),
-          label: Container(
-            padding: const EdgeInsets.only(left: 4),
-            alignment: Alignment.centerLeft,
-            child: Text(labelText),
-          ),
-          onPressed: onPressed,
-        ),
+          );
+        },
       );
     }
+    // In desktop, the width of button is limited by [AuthFormContainer]
     return SizedBox(
       height: 48,
-      width: double.infinity,
+      width: AuthFormContainer.width,
       child: OutlinedButton.icon(
         // In order to align all the labels vertically in a relatively centered position to the button, we use a fixed width container to wrap the icon(align to the right), then use another container to align the label to left.
         icon: Container(
-          width: buttonSize.width / 8,
+          width: AuthFormContainer.width / 4,
           alignment: Alignment.centerRight,
           child: SizedBox(
             // Some icons are not square, so we just use a fixed width here.

frontend/appflowy_flutter/lib/user/presentation/widgets/auth_form_container.dart

@@ -1,9 +1,8 @@
-import 'dart:math';
-
 import 'package:flutter/material.dart';
 
 class AuthFormContainer extends StatelessWidget {
   final List<Widget> children;
+  static const double width = 340;
   const AuthFormContainer({
     super.key,
     required this.children,
@@ -11,9 +10,8 @@ class AuthFormContainer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final size = MediaQuery.of(context).size;
     return SizedBox(
-      width: min(size.width, 340),
+      width: width,
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: children,