Mark conflicts in board

android/gradle.properties

 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
 android.enableJetifier=true
-app.versionName=0.0.12
-app.versionCode=12
+app.versionName=0.0.13
+app.versionCode=13

icons/build_game_icons.sh

@@ -54,6 +54,8 @@ function build_icon_for_skin() {
 }
 
 # Game icons
+build_icon ${CURRENT_DIR}/button_back.svg ${BASE_DIR}/assets/icons/button_back.png
+build_icon ${CURRENT_DIR}/button_show_conflicts.svg ${BASE_DIR}/assets/icons/button_show_conflicts.png
 build_icon ${CURRENT_DIR}/button_start.svg ${BASE_DIR}/assets/icons/button_start.png
 build_icon ${CURRENT_DIR}/difficulty_easy.svg ${BASE_DIR}/assets/icons/difficulty_easy.png
 build_icon ${CURRENT_DIR}/difficulty_medium.svg ${BASE_DIR}/assets/icons/difficulty_medium.png

icons/button_back.svg

+<?xml version="1.0" encoding="UTF-8"?>
+<svg enable-background="new 0 0 100 100" version="1.1" viewBox="0 0 93.665 93.676" xml:space="preserve" xmlns="http://www.w3.org/2000/svg"><path d="m46.834 11.248c-19.624 0-35.588 15.964-35.588 35.592 0 19.624 15.964 35.588 35.588 35.588s35.584-15.964 35.584-35.588c0-19.629-15.96-35.592-35.584-35.592zm0 63.607c-15.471 0-28.02-12.544-28.02-28.014 0-15.477 12.549-28.019 28.02-28.019s28.018 12.541 28.018 28.019c0 15.471-12.547 28.014-28.018 28.014z" stroke-width=".75985"/><path d="m55.403 64.285c0.85468 0.85879 3.0403 0.85879 3.0403 0v-34.893c0-0.85985-2.1908-0.85985-3.0486 0l-28.641 15.895c-0.8578 0.85468-0.87224 2.2454-0.0165 3.1032z" fill="#ed9138" stroke-width="1.031"/></svg>

icons/button_show_conflicts.svg

+<?xml version="1.0" encoding="UTF-8"?>
+<svg enable-background="new 0 0 100 100" version="1.1" viewBox="0 0 91.389 91.821" xml:space="preserve" xmlns="http://www.w3.org/2000/svg"><rect width="91.389" height="91.821" ry="0" fill="#e2b300"/><path d="m79.855 13.662a1.4083 1.4083 0 0 0-1.8775-0.11982l-26.365 20.293-1.1585-12.723a1.4009 1.4009 0 0 0-1.0985-1.2583 1.4367 1.4367 0 0 0-1.558 0.65904l-6.8708 11.644-9.6071-9.5472a1.4562 1.4562 0 0 0-1.6578-0.25965 1.4737 1.4737 0 0 0-0.77887 1.2782 0.972 0.972 0 0 0 0.02006 0.23979l2.177 13.182-21.052-3.4553a1.4314 1.4314 0 0 0-0.99866 2.6166l17.576 11.345-10.825 7.6299a1.4314 1.4314 0 0 0 0.81885 2.5965l12.783 0.13983-13.981 21.751a1.4236 1.4236 0 0 0 2.0972 1.8775l22.23-17.956 5.5725 6.4713a1.4509 1.4509 0 0 0 1.3582 0.45946 1.3606 1.3606 0 0 0 1.0786-0.9588l2.3967-7.1703 12.483 5.7723a1.4376 1.4376 0 0 0 1.6579-0.31951 1.451 1.451 0 0 0 0.19979-1.6777l-6.6512-11.784 13.062-3.5353a1.4274 1.4274 0 0 0 1.0586-1.3182 1.4045 1.4045 0 0 0-0.91882-1.3983l-12.583-4.7337 21.531-27.863a1.4082 1.4082 0 0 0-0.11982-1.8775z" stroke-width="2.0684"/></svg>

lib/entities/cell.dart

@@ -8,6 +8,7 @@ class Cell {
   final int col;
   final int row;
   bool isFixed;
+  int conflictsCount = 0;
 
   Cell(
     @required this.value,
@@ -28,7 +29,7 @@ class Cell {
     Color borderDarkColor = Colors.black;
     Color borderLightColor = Colors.grey;
     Color borderSelectedColor = Colors.red;
-    Color backgroundColor = this.isFixed ? Colors.grey[300] : Colors.grey[100];
+    Color backgroundColor = this.getBackgroundColor(myProvider);
 
     Border borders = Border(
       top: BorderSide(width: borderWidth, color: ((this.row % size) == 0) ? borderDarkColor : borderLightColor),
@@ -67,6 +68,29 @@ class Cell {
     );
   }
 
+  Color getBackgroundColor(Data myProvider) {
+    Color editableCellColor = Colors.grey[100];
+    Color editableCellColorConflict = Colors.pink[100];
+    Color fixedCellColor = Colors.grey[300];
+    Color fixedCellColorConflict = Colors.pink[200];
+
+    Color backgroundColor = editableCellColor;
+
+    if (this.isFixed) {
+      backgroundColor = fixedCellColor;
+    }
+
+    if (myProvider.showConflicts && (this.conflictsCount != 0)) {
+      if (this.isFixed) {
+        backgroundColor = fixedCellColorConflict;
+      } else {
+        backgroundColor = editableCellColorConflict;
+      }
+    }
+
+    return backgroundColor;
+  }
+
   Container widgetUpdateValue(Data myProvider) {
     String imageAsset = 'assets/skins/empty.png';
     if (this.value > 0) {

lib/provider/data.dart

@@ -15,6 +15,7 @@ class Data extends ChangeNotifier {
   String _level = 'medium';
   int _size = 3;
   String _skin = 'default';
+  bool _showConflicts = false;
 
   // Game data
   bool _stateRunning = false;
@@ -40,6 +41,12 @@ class Data extends ChangeNotifier {
     notifyListeners();
   }
 
+  bool get showConflicts => _showConflicts;
+  set updateShowConflicts(bool showConflicts) {
+    _showConflicts = showConflicts;
+    notifyListeners();
+  }
+
   getParameterValue(String parameterCode) {
     switch(parameterCode) {
       case 'difficulty': { return _level; }

lib/screens/home.dart

@@ -318,45 +318,65 @@ class Home extends StatelessWidget {
   bool _checkBoardIsSolved(Data myProvider) {
     List cells = myProvider.cells;
     int size = myProvider.size;
+    int sideLength = pow(size, 2);
+
+    bool isSolved = true;
+
+    // reset conflict states
+    for (var row = 0; row < sideLength; row++) {
+      for (var col = 0; col < sideLength; col++) {
+        cells[row][col].conflictsCount = 0;
+      }
+    }
 
     // check grid is fully completed
-    for (var row = 0; row < pow(size, 2); row++) {
-      for (var col = 0; col < pow(size, 2); col++) {
+    for (var row = 0; row < sideLength; row++) {
+      for (var col = 0; col < sideLength; col++) {
         if (cells[row][col].value == 0) {
-          print('grid not complete');
-          return false;
+          isSolved = false;
         }
       }
     }
-    print('ok grid complete');
 
     // check lines does not contains a value twice
-    for (var row = 0; row < pow(size, 2); row++) {
+    for (var row = 0; row < sideLength; row++) {
       List values = [];
-      for (var col = 0; col < pow(size, 2); col++) {
-        values.add(cells[row][col].value);
+      for (var col = 0; col < sideLength; col++) {
+        int value = cells[row][col].value;
+        if (value != 0) {
+          values.add(value);
+        }
       }
       List distinctValues = values.toSet().toList();
       if (values.length != distinctValues.length) {
         print('line ' + row.toString() + ' contains duplicates');
-        return false;
+        // Add line to cells in conflict
+        for (var col = 0; col < sideLength; col++) {
+          cells[row][col].conflictsCount++;
+        }
+        isSolved = false;
       }
     }
-    print('ok no line with duplicates');
 
     // check columns does not contains a value twice
-    for (var col = 0; col < pow(size, 2); col++) {
+    for (var col = 0; col < sideLength; col++) {
       List values = [];
-      for (var row = 0; row < pow(size, 2); row++) {
-        values.add(cells[row][col].value);
+      for (var row = 0; row < sideLength; row++) {
+        int value = cells[row][col].value;
+        if (value != 0) {
+          values.add(value);
+        }
       }
       List distinctValues = values.toSet().toList();
       if (values.length != distinctValues.length) {
         print('column ' + col.toString() + ' contains duplicates');
-        return false;
+        // Add column to cells in conflict
+        for (var row = 0; row < sideLength; row++) {
+          cells[row][col].conflictsCount++;
+        }
+        isSolved = false;
       }
     }
-    print('ok no column with duplicates');
 
     // check blocks does not contains a value twice
     for (var blockRow = 0; blockRow < size; blockRow++) {
@@ -367,37 +387,78 @@ class Home extends StatelessWidget {
           for (var colInBlock = 0; colInBlock < size; colInBlock++) {
             int row = (blockRow * size) + rowInBlock;
             int col = (blockCol * size) + colInBlock;
-            values.add(cells[row][col].value);
+            int value = cells[row][col].value;
+            if (value != 0) {
+              values.add(value);
+            }
           }
         }
 
         List distinctValues = values.toSet().toList();
         if (values.length != distinctValues.length) {
           print('block [' + blockCol.toString() + ',' + blockRow.toString() + '] contains duplicates');
-          return false;
+          // Add blocks to cells in conflict
+          for (var rowInBlock = 0; rowInBlock < size; rowInBlock++) {
+            for (var colInBlock = 0; colInBlock < size; colInBlock++) {
+              int row = (blockRow * size) + rowInBlock;
+              int col = (blockCol * size) + colInBlock;
+              cells[row][col].conflictsCount++;
+            }
+          }
+          isSolved = false;
         }
       }
     }
-    print('ok no block with duplicates');
 
-    print('-> ok sudoku solved!');
-    return true;
+    if (isSolved) {
+      print('-> ok sudoku solved!');
+    }
+
+    return isSolved;
   }
 
   @override
   Widget build(BuildContext context) {
     Data myProvider = Provider.of<Data>(context);
 
+    List<Widget> menuActions = [];
+
+    if (myProvider.stateRunning) {
+      menuActions.add(
+        FlatButton(
+          child: Container(
+            decoration: BoxDecoration(
+              borderRadius: BorderRadius.circular(4),
+              border: Border.all(
+                color: myProvider.showConflicts ? Colors.white : Colors.blue,
+                width: 4,
+              ),
+            ),
+            margin: EdgeInsets.all(8),
+            child: Image(
+              image: AssetImage('assets/icons/button_show_conflicts.png'),
+              fit: BoxFit.fill
+            ),
+          ),
+          onPressed: () { myProvider.updateShowConflicts = !myProvider.showConflicts; },
+        )
+      );
+
+      menuActions.add(
+        FlatButton(
+          child: Image(
+            image: AssetImage('assets/icons/button_back.png'),
+            fit: BoxFit.fill
+          ),
+          onPressed: () => resetGame(myProvider),
+        ),
+      );
+    }
+
     return Scaffold(
       appBar: AppBar(
         title: Text('🔢'),
-        actions: [
-          if (myProvider.stateRunning)
-            FlatButton(
-              child: Text('◀️'),
-              onPressed: () => resetGame(myProvider),
-            ),
-        ],
+        actions: menuActions,
       ),
       body: SafeArea(
         child: Center(