Added a undo button. Therefore a note can pushed back into current tasks from completed tasks.

Author: sai-manjunath-1729

lib/completedTasks.dart

@@ -15,11 +15,19 @@ class _CompletedTasksState extends State<CompletedTasks> {
     List<Note> completedTasks = Storage.completedNotes;
     return ListView.builder(
       itemBuilder: (BuildContext context, int index) {
-        return NoteCardCompleted(note: completedTasks[index], myFunc: () {
-          setState(() {
-            Storage.removeNoteCompleted(note: completedTasks[index]);
-          });
-        });
+        return NoteCardCompleted(
+          note: completedTasks[index],
+          myFunc: () {
+            setState(() {
+              Storage.removeNoteCompleted(note: completedTasks[index]);
+            });
+          },
+          undo: () {
+            setState(() {
+              Storage.undo(note: completedTasks[index]);
+            });
+          },
+        );
       },
       itemCount: completedTasks.length,
     );

lib/note.dart

@@ -88,7 +88,8 @@ class NoteCard extends StatelessWidget {
 class NoteCardCompleted extends StatelessWidget {
   final Note note;
   final VoidCallback myFunc;
-  NoteCardCompleted({required this.note, required this.myFunc});
+  final VoidCallback undo;
+  NoteCardCompleted({required this.note, required this.myFunc, required this.undo});
 
   @override
   Widget build(BuildContext context) {
@@ -141,14 +142,14 @@ class NoteCardCompleted extends StatelessWidget {
                 ),
               ],
             ),
-            IconButton(onPressed: myFunc, icon: Icon(Icons.delete_rounded)),
-            // Row(
-            //   mainAxisAlignment: MainAxisAlignment.spaceAround,
-            //   children: <Widget>[
-            //     IconButton(onPressed: myFunc, icon: Icon(Icons.delete_rounded)),
-            //     IconButton(onPressed: myFunc, icon: Icon(Icons.check)),
-            //   ],
-            // ),
+            // IconButton(onPressed: myFunc, icon: Icon(Icons.delete_rounded)),
+            Row(
+              mainAxisAlignment: MainAxisAlignment.spaceAround,
+              children: <Widget>[
+                IconButton(onPressed: myFunc, icon: Icon(Icons.delete_rounded)),
+                IconButton(onPressed: undo, icon: Icon(Icons.undo)),
+              ],
+            ),
           ],
         ),
       ),

lib/storage.dart

@@ -66,4 +66,17 @@ class Storage {
       }
     }
   }
+
+  static void undo({required Note note}) {
+    notes.add(note);
+    localStorage.add(note);
+    completedNotes.remove(note);
+
+    for(var k in completed.keys) {
+      if(note == completed.get(k)) {
+        completed.delete(k);
+        break;
+      }
+    }
+  }
 }