lib/utils/board_animate.dart

 import 'dart:async';
 
-import '../entities/cell.dart';
 import '../provider/data.dart';
 
 class BoardAnimate {
-
   // Start game animation: blinking tiles
   static List createStartGameAnimationPatterns(Data myProvider) {
     List<List> patterns = [];
@@ -89,9 +87,8 @@ class BoardAnimate {
 
     myProvider.updateAnimationInProgress(true);
 
-    Timer _timerAnimateBoard;
     const interval = const Duration(milliseconds: 200);
-    _timerAnimateBoard = new Timer.periodic(
+    new Timer.periodic(
       interval,
       (Timer timer) {
         if (_patternIndex == 0) {

lib/utils/board_utils.dart

@@ -5,7 +5,6 @@ import '../provider/data.dart';
 import '../utils/random_pick_grid.dart';
 
 class BoardUtils {
-
   static printGrid(List cells, List solvedCells) {
     String stringValues = '0123456789ABCDEFG';
     print('');
@@ -24,15 +23,13 @@ class BoardUtils {
   }
 
   static Future<void> pickGrid(Data myProvider) async {
-    String grid;
+    String grid = '';
     RandomPickGrid randomPickGrid;
 
     randomPickGrid = RandomPickGrid();
-    await randomPickGrid.init(myProvider.level, myProvider.size);
+    await randomPickGrid.init(myProvider.parameterLevel, myProvider.parameterSize);
 
-    if (randomPickGrid.grid != null) {
     grid = randomPickGrid.grid;
-    }
 
     int blockSizeHorizontal = myProvider.blockSizeHorizontal;
     int blockSizeVertical = myProvider.blockSizeVertical;
@@ -107,21 +104,25 @@ class BoardUtils {
     print('rotate board: ' + rotate);
 
     switch (flip) {
-      case 'horizontal': {
+      case 'horizontal':
+        {
           List transformedBoard = createEmptyBoard(boardSize);
           for (var rowIndex = 0; rowIndex < boardSize; rowIndex++) {
             for (var colIndex = 0; colIndex < boardSize; colIndex++) {
-            transformedBoard[rowIndex][colIndex].value = cells[boardSize - rowIndex - 1][colIndex].value;
+              transformedBoard[rowIndex][colIndex].value =
+                  cells[boardSize - rowIndex - 1][colIndex].value;
             }
           }
           cells = transformedBoard;
         }
         break;
-      case 'vertical': {
+      case 'vertical':
+        {
           List transformedBoard = createEmptyBoard(boardSize);
           for (var rowIndex = 0; rowIndex < boardSize; rowIndex++) {
             for (var colIndex = 0; colIndex < boardSize; colIndex++) {
-            transformedBoard[rowIndex][colIndex].value = cells[rowIndex][boardSize - colIndex - 1].value;
+              transformedBoard[rowIndex][colIndex].value =
+                  cells[rowIndex][boardSize - colIndex - 1].value;
             }
           }
           cells = transformedBoard;
@@ -130,21 +131,25 @@ class BoardUtils {
     }
 
     switch (rotate) {
-      case 'left': {
+      case 'left':
+        {
           List transformedBoard = createEmptyBoard(boardSize);
           for (var rowIndex = 0; rowIndex < boardSize; rowIndex++) {
             for (var colIndex = 0; colIndex < boardSize; colIndex++) {
-            transformedBoard[rowIndex][colIndex].value = cells[colIndex][boardSize - rowIndex - 1].value;
+              transformedBoard[rowIndex][colIndex].value =
+                  cells[colIndex][boardSize - rowIndex - 1].value;
             }
           }
           cells = transformedBoard;
         }
         break;
-      case 'right': {
+      case 'right':
+        {
           List transformedBoard = createEmptyBoard(boardSize);
           for (var rowIndex = 0; rowIndex < boardSize; rowIndex++) {
             for (var colIndex = 0; colIndex < boardSize; colIndex++) {
-            transformedBoard[rowIndex][colIndex].value = cells[boardSize - colIndex - 1][rowIndex].value;
+              transformedBoard[rowIndex][colIndex].value =
+                  cells[boardSize - colIndex - 1][rowIndex].value;
             }
           }
           cells = transformedBoard;
@@ -155,7 +160,8 @@ class BoardUtils {
     // Fix cells fixed states
     for (var rowIndex = 0; rowIndex < boardSize; rowIndex++) {
       for (var colIndex = 0; colIndex < boardSize; colIndex++) {
-        cells[rowIndex][colIndex].isFixed = (cells[rowIndex][colIndex].value != 0) ? true : false;
+        cells[rowIndex][colIndex].isFixed =
+            (cells[rowIndex][colIndex].value != 0) ? true : false;
       }
     }
 
@@ -170,8 +176,6 @@ class BoardUtils {
 
     int boardSize = blockSizeHorizontal * blockSizeVertical;
 
-    bool isSolved = true;
-
     // (re)compute conflicts
     BoardUtils.computeConflictsInBoard(myProvider);
 
@@ -189,8 +193,9 @@ class BoardUtils {
     return true;
   }
 
-  static bool isValueAllowed(List cells, int blockSizeHorizontal, int blockSizeVertical, int candidateCol, int candidateRow, int candidateValue) {
-    if (candidateValue == 0) {
+  static bool isValueAllowed(List cells, int blockSizeHorizontal, int blockSizeVertical,
+      int? candidateCol, int? candidateRow, int candidateValue) {
+    if ((candidateCol == null) || (candidateRow == null) || (candidateValue == 0)) {
       return true;
     }
 
@@ -336,7 +341,11 @@ class BoardUtils {
 
         List distinctValues = values.toSet().toList();
         if (values.length != distinctValues.length) {
-          print('block [' + blockCol.toString() + ',' + blockRow.toString() + '] contains duplicates');
+          print('block [' +
+              blockCol.toString() +
+              ',' +
+              blockRow.toString() +
+              '] contains duplicates');
           // Add blocks to cells in conflict
           for (var rowInBlock = 0; rowInBlock < blockSizeVertical; rowInBlock++) {
             for (var colInBlock = 0; colInBlock < blockSizeHorizontal; colInBlock++) {
@@ -350,13 +359,15 @@ class BoardUtils {
     }
   }
 
-  static List getCellsWithWrongValue(List cells, List cellsSolved, int blockSizeHorizontal, int blockSizeVertical) {
+  static List getCellsWithWrongValue(
+      List cells, List cellsSolved, int blockSizeHorizontal, int blockSizeVertical) {
     List cellsWithWrongValue = [];
     int boardSize = blockSizeHorizontal * blockSizeVertical;
 
     for (var row = 0; row < boardSize; row++) {
       for (var col = 0; col < boardSize; col++) {
-        if (cells[row][col].value != 0 && cells[row][col].value != cellsSolved[row][col].value) {
+        if (cells[row][col].value != 0 &&
+            cells[row][col].value != cellsSolved[row][col].value) {
           cellsWithWrongValue.add([col, row]);
         }
       }
@@ -372,7 +383,9 @@ class BoardUtils {
     for (var row = 0; row < boardSize; row++) {
       for (var col = 0; col < boardSize; col++) {
         if (!cells[row][col].isFixed && cells[row][col].value != 0) {
-          if (cells[row][col].conflictsCount != 0 && !BoardUtils.isValueAllowed(cells, blockSizeHorizontal, blockSizeVertical, col, row, cells[row][col].value)) {
+          if (cells[row][col].conflictsCount != 0 &&
+              !BoardUtils.isValueAllowed(cells, blockSizeHorizontal, blockSizeVertical, col,
+                  row, cells[row][col].value)) {
             conflictingCells.add([col, row]);
           }
         }
@@ -382,7 +395,8 @@ class BoardUtils {
     return conflictingCells;
   }
 
-  static List getCellsWithUniqueAvailableValue(List cells, int blockSizeHorizontal, int blockSizeVertical) {
+  static List getCellsWithUniqueAvailableValue(
+      List cells, int blockSizeHorizontal, int blockSizeVertical) {
     List candidateCells = [];
     int boardSize = blockSizeHorizontal * blockSizeVertical;
 
@@ -392,7 +406,8 @@ class BoardUtils {
           int allowedValuesCount = 0;
           int candidateValue = 0;
           for (var value = 1; value <= boardSize; value++) {
-            if (BoardUtils.isValueAllowed(cells, blockSizeHorizontal, blockSizeVertical, col, row, value)) {
+            if (BoardUtils.isValueAllowed(
+                cells, blockSizeHorizontal, blockSizeVertical, col, row, value)) {
               candidateValue = value;
               allowedValuesCount++;
             }
@@ -413,7 +428,8 @@ class BoardUtils {
     int blockSizeVertical = myProvider.blockSizeVertical;
 
     do {
-      List cellsWithUniqueAvailableValue = BoardUtils.getCellsWithUniqueAvailableValue(cells, blockSizeHorizontal, blockSizeVertical);
+      List cellsWithUniqueAvailableValue = BoardUtils.getCellsWithUniqueAvailableValue(
+          cells, blockSizeHorizontal, blockSizeVertical);
       if (cellsWithUniqueAvailableValue.length == 0) {
         break;
       }
@@ -427,5 +443,4 @@ class BoardUtils {
 
     return cells;
   }
-
 }

lib/utils/game_utils.dart

 import '../provider/data.dart';
 import '../utils/board_animate.dart';
 import '../utils/board_utils.dart';
-import '../utils/game_utils.dart';
 
 class GameUtils {
-
   static Future<void> resetGame(Data myProvider) async {
     myProvider.updateGameIsRunning(false);
   }
 
   static Future<void> startGame(Data myProvider) async {
-    myProvider.updateSize(myProvider.size);
+    myProvider.updateParameterSize(myProvider.parameterSize);
     myProvider.updateGameIsRunning(true);
     myProvider.resetGivenTipsCount();
     myProvider.shuffleCellValues();
-    myProvider.updateCells(BoardUtils.createEmptyBoard(myProvider.blockSizeHorizontal * myProvider.blockSizeVertical));
+    myProvider.updateCells(BoardUtils.createEmptyBoard(
+        myProvider.blockSizeHorizontal * myProvider.blockSizeVertical));
     BoardUtils.pickGrid(myProvider);
     BoardAnimate.startAnimation(myProvider, 'start');
   }
@@ -36,21 +35,24 @@ class GameUtils {
     int blockSizeVertical = myProvider.blockSizeVertical;
 
     // pick one of wrong value cells, if found
-    List wrongValueCells = BoardUtils.getCellsWithWrongValue(cells, myProvider.cellsSolved, blockSizeHorizontal, blockSizeVertical);
+    List wrongValueCells = BoardUtils.getCellsWithWrongValue(
+        cells, myProvider.cellsSolved, blockSizeHorizontal, blockSizeVertical);
     if (wrongValueCells.length != 0) {
       GameUtils.pickRandomFromList(myProvider, wrongValueCells);
       return;
     }
 
     // pick one of conflicting cells, if found
-    List conflictingCells = BoardUtils.getCellsWithUniqueAvailableValue(cells, blockSizeHorizontal, blockSizeVertical);
+    List conflictingCells = BoardUtils.getCellsWithUniqueAvailableValue(
+        cells, blockSizeHorizontal, blockSizeVertical);
     if (conflictingCells.length != 0) {
       GameUtils.pickRandomFromList(myProvider, conflictingCells);
       return;
     }
 
     //  pick one form cells with unique non-conflicting candidate value
-    List candidateCells = BoardUtils.getCellsWithUniqueAvailableValue(cells, blockSizeHorizontal, blockSizeVertical);
+    List candidateCells = BoardUtils.getCellsWithUniqueAvailableValue(
+        cells, blockSizeHorizontal, blockSizeVertical);
     if (candidateCells.length != 0) {
       GameUtils.pickRandomFromList(myProvider, candidateCells);
       return;
@@ -78,17 +80,18 @@ class GameUtils {
     // ensure there is only one eligible value for this cell
     int allowedValuesCount = 0;
     for (var value = 1; value <= boardSize; value++) {
-      if (BoardUtils.isValueAllowed(cells, blockSizeHorizontal, blockSizeVertical, myProvider.currentCellCol, myProvider.currentCellRow, value)) {
+      if (BoardUtils.isValueAllowed(cells, blockSizeHorizontal, blockSizeVertical,
+          myProvider.currentCellCol, myProvider.currentCellRow, value)) {
         allowedValuesCount++;
         eligibleValue = value;
       }
     }
 
-    myProvider.updateCellValue(myProvider.currentCellCol, myProvider.currentCellRow, allowedValuesCount == 1 ? eligibleValue : 0);
+    myProvider.updateCellValue(myProvider.currentCellCol, myProvider.currentCellRow,
+        allowedValuesCount == 1 ? eligibleValue : 0);
     myProvider.selectCell(null, null);
     if (BoardUtils.checkBoardIsSolved(myProvider)) {
       BoardAnimate.startAnimation(myProvider, 'win');
     }
   }
-
 }

lib/utils/random_pick_grid.dart

@@ -4,27 +4,27 @@ import 'package:flutter/services.dart';
 class RandomPickGrid {
   RandomPickGrid();
 
-  String _grid;
+  String _grid = '';
 
-  init(String difficulty, String size) async {
+  init(String level, String size) async {
     _grid = '';
-    await gridFromLocalFile(difficulty, size);
+    await gridFromLocalFile(level, size);
   }
 
-  Future<void> gridFromLocalFile(String difficulty, String size) async {
+  Future<void> gridFromLocalFile(String level, String size) async {
     // Get global grids list
-    List grids;
+    List grids = [];
     try {
       String jsonString = await rootBundle.loadString('assets/files/templates.json');
       final jsonResponse = await json.decode(jsonString);
-      grids = jsonResponse['templates'][size][difficulty];
+      grids = jsonResponse['templates'][size][level];
     } catch (e) {
       print("$e");
     }
 
     // Check we have enough grids
     if (grids.length < 1) {
-      print('Not enough grids [' + size + ', ' + difficulty + '] in templates.');
+      print('Not enough grids [' + size + ', ' + level + '] in templates.');
     }
 
     // Randomize grids list

pubspec.lock

@@ -14,7 +14,7 @@ packages:
       name: badges
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.2"
+    version: "2.0.3"
   boolean_selector:
     dependency: transitive
     description:
@@ -63,7 +63,7 @@ packages:
       name: ffi
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "2.0.1"
   file:
     dependency: transitive
     description:
@@ -127,7 +127,7 @@ packages:
       name: overlay_support
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.1"
+    version: "2.0.1"
   path:
     dependency: transitive
     description:
@@ -141,21 +141,21 @@ packages:
       name: path_provider_linux
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.5"
+    version: "2.1.7"
   path_provider_platform_interface:
     dependency: transitive
     description:
       name: path_provider_platform_interface
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.3"
+    version: "2.0.4"
   path_provider_windows:
     dependency: transitive
     description:
       name: path_provider_windows
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.5"
+    version: "2.1.0"
   platform:
     dependency: transitive
     description:
@@ -183,42 +183,42 @@ packages:
       name: provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "6.0.2"
+    version: "6.0.3"
   shared_preferences:
     dependency: "direct main"
     description:
       name: shared_preferences
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.13"
+    version: "2.0.15"
   shared_preferences_android:
     dependency: transitive
     description:
       name: shared_preferences_android
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.11"
+    version: "2.0.12"
   shared_preferences_ios:
     dependency: transitive
     description:
       name: shared_preferences_ios
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.10"
+    version: "2.1.1"
   shared_preferences_linux:
     dependency: transitive
     description:
       name: shared_preferences_linux
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   shared_preferences_macos:
     dependency: transitive
     description:
       name: shared_preferences_macos
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.3"
+    version: "2.0.4"
   shared_preferences_platform_interface:
     dependency: transitive
     description:
@@ -232,14 +232,14 @@ packages:
       name: shared_preferences_web
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.3"
+    version: "2.0.4"
   shared_preferences_windows:
     dependency: transitive
     description:
       name: shared_preferences_windows
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -300,7 +300,7 @@ packages:
       name: win32
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.4.0"
+    version: "2.7.0"
   xdg_directories:
     dependency: transitive
     description:
@@ -309,5 +309,5 @@ packages:
     source: hosted
     version: "0.2.0+1"
 sdks:
-  dart: ">=2.17.0-0 <3.0.0"
-  flutter: ">=2.8.0"
+  dart: ">=2.17.0 <3.0.0"
+  flutter: ">=3.0.0"

pubspec.yaml

@@ -4,7 +4,7 @@ publish_to: 'none'
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.16.1 <3.0.0"
 
 dependencies:
   flutter:
@@ -12,7 +12,7 @@ dependencies:
   provider: ^6.0.2
   badges: ^2.0.1
   shared_preferences: ^2.0.6
-  overlay_support: ^1.0.0
+  overlay_support: ^2.0.1
 
 dev_dependencies:
   flutter_test:

test/widget_test.dart

-// This is a basic Flutter widget test.
-//
-// To perform an interaction with a widget in your test, use the WidgetTester
-// utility that Flutter provides. For example, you can send tap and scroll
-// gestures. You can also use WidgetTester to find child widgets in the widget
-// tree, read text, and verify that the values of widget properties are correct.
-
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-import 'package:sudoku/main.dart';
-
-void main() {
-}