feat: make the transition when navigating to the introduction screen more fluent

packages/firebase_introduction_repository/lib/src/firebase_introduction_repository.dart

@@ -7,12 +7,18 @@ import "package:introduction_repository_interface/introduction_repository_interf
 
 class FirebaseIntroductionRepository
     implements IntroductionRepositoryInterface {
+  bool? _shouldShowIntroduction;
+  List<IntroductionPageData>? _introductionPages;
+
   final _introductionCollection = FirebaseFirestore.instance
       .collection("flutter_introduction")
       .doc("flutter_introduction");
 
   @override
   Future<List<IntroductionPageData>> fetchIntroductionPages() async {
+    if (_introductionPages != null) {
+      return _introductionPages!;
+    }
     try {
       var introductionPagesData = await _introductionCollection
           .collection("pages")
@@ -27,6 +33,7 @@ class FirebaseIntroductionRepository
           introductionPagesData.docs.map((e) => e.data()).toList();
 
       introductionPages.sort((a, b) => a.id.compareTo(b.id));
+      _introductionPages = introductionPages;
       return introductionPages;
     } on Exception catch (_) {
       throw Exception();
@@ -51,6 +58,9 @@ class FirebaseIntroductionRepository
 
   @override
   Future<bool> shouldShow() async {
+    if (_shouldShowIntroduction != null) {
+      return _shouldShowIntroduction!;
+    }
     try {
       await FirebaseAuth.instance.signInAnonymously();
       var deviceId = await _getDeviceId();
@@ -64,8 +74,10 @@ class FirebaseIntroductionRepository
       if (!introductionCompleted.exists) {
         return true;
       }
+      _shouldShowIntroduction =
           // ignore: avoid_dynamic_calls
-      return !introductionCompleted.data()!["introduction_completed"];
+          !introductionCompleted.data()!["introduction_completed"];
+      return _shouldShowIntroduction!;
     } on Exception catch (_) {
       throw Exception();
     }
@@ -83,4 +95,10 @@ class FirebaseIntroductionRepository
     }
     return null;
   }
+
+  @override
+  Future<void> prefetchIntroduction() async {
+    await shouldShow();
+    await fetchIntroductionPages();
+  }
 }

packages/flutter_introduction/lib/src/widgets/button.dart

@@ -17,16 +17,12 @@ class Button extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     var theme = Theme.of(context);
-
     return Expanded(
-      child: ConstrainedBox(
-        constraints: const BoxConstraints(
-          maxWidth: 180,
-          maxHeight: 32,
-        ),
       child: showButton
           ? FilledButton(
               style: ButtonStyle(
+                tapTargetSize: MaterialTapTargetSize.shrinkWrap,
+                minimumSize: WidgetStateProperty.all(const Size(160, 32)),
                 backgroundColor: WidgetStateProperty.all(
                   introductionTheme.buttonBackgroundColor,
                 ),
@@ -47,8 +43,7 @@ class Button extends StatelessWidget {
                     theme.textTheme.bodyMedium,
               ),
             )
-            : const SizedBox(),
+          : const SizedBox.shrink(),
-      ),
     );
   }
 }

packages/flutter_introduction/lib/src/widgets/introduction_page.dart

@@ -1,7 +1,5 @@
 import "package:flutter/material.dart";
 import "package:flutter_introduction/flutter_introduction.dart";
-import "package:flutter_introduction/src/config/introduction_theme.dart";
-import "package:flutter_introduction/src/enums/introduction_layout_style.dart";
 
 class IntroductionPage extends StatelessWidget {
   const IntroductionPage({

packages/introduction_repository_interface/lib/src/interfaces/introduction_repository_interface.dart

@@ -7,4 +7,6 @@ abstract class IntroductionRepositoryInterface {
   Future<void> setCompleted({bool value = true});
 
   Future<bool> shouldShow();
+
+  Future<void> prefetchIntroduction();
 }

packages/introduction_repository_interface/lib/src/local/local_introduction_repository.dart

@@ -11,7 +11,11 @@ class LocalIntroductionRepository implements IntroductionRepositoryInterface {
   Future<bool> shouldShow() async => !_completed;
 
   @override
-  Future<List<IntroductionPageData>> fetchIntroductionPages() {
+  Future<List<IntroductionPageData>> fetchIntroductionPages() async => [];
-    throw Exception();
+
+  @override
+  Future<void> prefetchIntroduction() async {
+    await shouldShow();
+    await fetchIntroductionPages();
   }
 }

packages/introduction_repository_interface/lib/src/services/introduction_service.dart

@@ -16,4 +16,7 @@ class IntroductionService {
 
   Future<bool> shouldShow() async =>
       introductionRepositoryInterface.shouldShow();
+
+  Future<void> prefetchIntroduction() async =>
+      introductionRepositoryInterface.prefetchIntroduction();
 }

packages/shared_preferences_introduction_repository/lib/src/shared_preferences_introduction_repository.dart

@@ -3,10 +3,10 @@ import "package:shared_preferences/shared_preferences.dart";
 
 class SharedPreferencesIntroductionRepository
     implements IntroductionRepositoryInterface {
+  bool? _shouldShowIntroduction;
+
   @override
-  Future<List<IntroductionPageData>> fetchIntroductionPages() async {
+  Future<List<IntroductionPageData>> fetchIntroductionPages() async => [];
-    throw Exception();
-  }
 
   @override
   Future<void> setCompleted({bool value = true}) async {
@@ -16,8 +16,18 @@ class SharedPreferencesIntroductionRepository
 
   @override
   Future<bool> shouldShow() async {
+    if (_shouldShowIntroduction != null) {
+      return !_shouldShowIntroduction!;
+    }
     var sharedPrefs = await SharedPreferences.getInstance();
     var shouldShow = sharedPrefs.getBool("_completedIntroduction") ?? true;
-    return !shouldShow;
+    _shouldShowIntroduction = shouldShow;
+    return !_shouldShowIntroduction!;
+  }
+
+  @override
+  Future<void> prefetchIntroduction() async {
+    await shouldShow();
+    await fetchIntroductionPages();
   }
 }