Hot fixed storage issue

Futures and Async code is hard
martin-headspace · Feb 17, 2020 · d2036ea · d2036ea
1 parent 8deaa66
commit d2036ea
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Showing 3 changed files with 22 additions and 21 deletions.
diff --git a/eight_queens/lib/main.dart b/eight_queens/lib/main.dart
@@ -68,7 +68,7 @@ class _MyHomePageState extends State<MyHomePage> {
     await QueenResolver().solve(_boardSize);
     pr.dismiss();
 
-    Navigator.push(context, MaterialPageRoute(builder: (context) => ResultsPage(title: "Results")));
+    await Navigator.push(context, MaterialPageRoute(builder: (context) => ResultsPage(title: "Results")));
   }
 
   @override

diff --git a/eight_queens/lib/queens.dart b/eight_queens/lib/queens.dart
@@ -7,7 +7,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 
 class QueenResolver {
 
-  List<List<List<int>>> boards = new List();
+  int count = 0;
 
   Future<bool> _isSafe(board, int row, int col, int n) async {
       // Check row on the left side
@@ -43,8 +43,10 @@ class QueenResolver {
   Future<bool> _solveQueens(board, int col, int n) async {
 
     if (col >= n) {
-      _storeSolution(board);
-      return true;
+      count++;
+      _storeSolution(board).then((value) {
+        return true;
+      });
     }
 
     var res = false;
@@ -58,28 +60,19 @@ class QueenResolver {
     return res;
   }
 
-  _storeSolution(List<List<int>> board) async {
+  Future _storeSolution(List<List<int>> board) async {
     for(int i = 0; i < board.length; i++) {
       for(int x = 0; x < board[i].length ; x++) {
         if(board[i][x] == null) {
           board[i][x] = 0;
         }
       }
     }
-
-    boards.add(board);
-    await _saveToLocalStorage();
-  }
-
-  Future<bool> _saveToLocalStorage() async {
-    SharedPreferences.setMockInitialValues({});
     final prefs = await SharedPreferences.getInstance();
-    prefs.setString('result', boards.toString());
+    await prefs.setString('board'+count.toString(), board.toString());
+    await prefs.setInt('count', count);
   }
 
-
-
-
   Future<bool> solve(int n) async {
     // Create the initial queens board
      List<List<int>> board = new List.generate(n, (_) => new List(n));

diff --git a/eight_queens/lib/results.dart b/eight_queens/lib/results.dart
@@ -12,22 +12,30 @@ class ResultsPage extends StatefulWidget {
 }
 
 class _ResultsPageState extends State<ResultsPage> {
-  var boards;
+  var boards = new List();
 
   Future retrieveEightQueensResults() async {
     final prefs = await SharedPreferences.getInstance();
-    String boardsString = await prefs.get('result');
+    int count = await prefs.getInt("count");
+    print(count);
+    var _boards = new List();
+    for(int i = 1 ; i < count + 1; i++) {
+      String s_board = prefs.getString('board'+i.toString());
+      var board = jsonDecode(s_board);
+      _boards.add(board);
+    }
+
     setState(() {
-      boards = jsonDecode(boardsString);
+      boards = _boards;
     });
   }
 
   @override
   void initState() {
     retrieveEightQueensResults().then((value) {
       print('async done');
+      super.initState();
     });
-    super.initState();
   }
 
   @override
@@ -37,7 +45,7 @@ class _ResultsPageState extends State<ResultsPage> {
         title: Text(widget.title),
       ),
       body: new ListView.builder(
-        itemCount: boards.length,
+        itemCount: boards.length ?? 0,
         itemBuilder: (BuildContext context, int index) {
           return new Text(boards[index].toString());
         },