Add ItemType for determining which DB methods should be called based on the screen data. Begin implementing it.

lib/models/expense.dart

@@ -1,4 +1,6 @@
 // Local
+import 'package:flutter_expense_tracker/models/item_type.dart';
+
 import '/models/tracked_item.dart';
 import '/models/frequency.dart';
 
@@ -7,6 +9,7 @@ class Expense extends TrackedItem {
 
   Expense({
     super.id,
+    super.type = ItemType.expense,
     required super.name,
     required super.amount,
     required super.frequency,

lib/models/item_type.dart

@@ -0,0 +1,22 @@
+enum ItemType {
+  expense(
+    title: "Expense",
+    plural: "Expenses",
+  ),
+  income(
+    title: "Income",
+    plural: "Incomes",
+  ),
+  asset(
+    title: "Asset",
+    plural: "Assets",
+  );
+
+  const ItemType({
+    required this.title,
+    required this.plural,
+  });
+
+  final String title;
+  final String plural;
+}

lib/models/tracked_item.dart

@@ -1,8 +1,11 @@
 // Local
+import 'package:flutter_expense_tracker/models/item_type.dart';
+
 import '/models/frequency.dart';
 
 abstract class TrackedItem {
   int? id;
+  ItemType? type;
   String name;
   double amount;
   Frequency? frequency;
@@ -10,6 +13,7 @@ abstract class TrackedItem {
 
   TrackedItem({
     this.id,
+    this.type,
     required this.name,
     required this.amount,
     this.frequency,

lib/pages/asset.dart

@@ -1,12 +0,0 @@
-import 'package:flutter/material.dart';
-
-class AssetPage extends StatelessWidget {
-  const AssetPage({
-    super.key,
-  });
-
-  @override
-  Widget build(BuildContext context) {
-    return Placeholder();
-  }
-}

lib/pages/home.dart

@@ -1,14 +1,14 @@
 // Flutter
 import 'package:flutter/material.dart';
+import 'package:flutter_expense_tracker/models/item_type.dart';
 import 'dart:io';
 
 // Local
-import '/pages/expense.dart';
+import '/pages/tracked_item.dart';
-import '/pages/income.dart';
-import '/pages/asset.dart';
 import '/pages/report.dart';
 import '/pages/settings.dart';
 import '/pages/help.dart';
+import '/db.dart';
 
 class HomePage extends StatefulWidget {
   const HomePage({
@@ -32,14 +32,15 @@ class _HomePageState extends State<HomePage> {
     Widget? dialog;
     switch (pageSelected) {
       case 0:
-        page = ExpensePage();
+        page = TrackedItemPage(assetsToLoad: DatabaseHelper.instance.getExpenses());
         dialog = TrackedItemInputDialog(
           notifyParent: refresh,
+          type: ItemType.expense,
         );
       case 1:
-        page = IncomePage();
+        page = Placeholder();
       case 2:
-        page = AssetPage();
+        page = Placeholder();
       case 3:
         page = ProjectionPage();
       case 4:

lib/pages/income.dart

@@ -1,12 +0,0 @@
-import 'package:flutter/material.dart';
-
-class IncomePage extends StatelessWidget {
-  const IncomePage({
-    super.key,
-  });
-
-  @override
-  Widget build(BuildContext context) {
-    return Placeholder();
-  }
-}

lib/pages/tracked_item.dart

@@ -1,24 +1,30 @@
 // Flutter
 import 'package:flutter/material.dart';
+import 'package:flutter_expense_tracker/models/asset.dart';
+import 'package:flutter_expense_tracker/models/income.dart';
 
 // Local
 import '/models/tracked_item.dart';
+import '/models/item_type.dart';
 import '/models/expense.dart';
 import '/models/frequency.dart';
 import '/db.dart';
 
 // TODO: Make this a generic UI based on a superclass of Expense, Income, and Assets.
 
-class ExpensePage extends StatefulWidget {
+class TrackedItemPage extends StatefulWidget {
-  const ExpensePage({
+  final Future<List<TrackedItem>> assetsToLoad;
+
+  const TrackedItemPage({
     super.key,
+    required this.assetsToLoad,
   });
 
   @override
-  State<ExpensePage> createState() => _ExpensePageState();
+  State<TrackedItemPage> createState() => _TrackedItemPageState();
 }
 
-class _ExpensePageState extends State<ExpensePage> {
+class _TrackedItemPageState extends State<TrackedItemPage> {
   refresh() {
     setState(() {});
   }
@@ -28,9 +34,9 @@ class _ExpensePageState extends State<ExpensePage> {
     final theme = Theme.of(context);
 
     return FutureBuilder<List<TrackedItem>>(
-        future: DatabaseHelper.instance.getExpenses(),
+        future: widget.assetsToLoad,
-        builder: (BuildContext context,
+        builder:
-            AsyncSnapshot<List<TrackedItem>> snapshot) {
+            (BuildContext context, AsyncSnapshot<List<TrackedItem>> snapshot) {
           if (!snapshot.hasData) {
             return Text('Loading...');
           }
@@ -41,13 +47,12 @@ class _ExpensePageState extends State<ExpensePage> {
           );
           return snapshot.data!.isEmpty
               ? Text(
-                  "Add expenses to get started.",
+                  "Add items to get started.",
                   softWrap: true,
                 )
               : ListView.builder(
                   itemCount: snapshot.data!.length,
                   itemBuilder: (_, index) {
-                    //List<Expense> expenses = snapshot.data!;
                     final TrackedItem curr = snapshot.data![index];
 
                     final itemKey = Key(curr.id!.toString());
@@ -139,7 +144,17 @@ class _ExpensePageState extends State<ExpensePage> {
                             snapshot.data!.remove(curr);
                             switch (direction) {
                               case DismissDirection.startToEnd:
-                                DatabaseHelper.instance.removeExpense(curr.id!);
+                                if (curr is Expense) {
+                                  DatabaseHelper.instance
+                                      .removeExpense(curr.id!);
+                                } else if (curr is Income) {
+                                  // TODO
+                                } else if (curr is Asset) {
+                                  // TODO
+                                } else {
+                                  throw UnimplementedError(
+                                      "Cannot remove unimplemented item type.");
+                                }
                                 break;
                               case DismissDirection.endToStart:
                                 // Open an edit dialog, then remove the item from the list.
@@ -150,6 +165,7 @@ class _ExpensePageState extends State<ExpensePage> {
                                       notifyParent: refresh,
                                       entry: curr,
                                       amountText: curr.getAmountText(),
+                                      type: curr.type!,
                                     ),
                                   ),
                                 );
@@ -230,22 +246,22 @@ class TrackedItemInputDialog extends StatefulWidget {
   final Function() notifyParent;
   final TrackedItem? entry;
   final String? amountText;
+  final ItemType? type;
 
   const TrackedItemInputDialog({
     super.key,
     required this.notifyParent,
     this.entry,
     this.amountText,
+    this.type,
   });
 
   @override
-  State<TrackedItemInputDialog> createState() =>
+  State<TrackedItemInputDialog> createState() => _TrackedItemInputDialogState();
-      _TrackedItemInputDialogState();
 }
 
-class _TrackedItemInputDialogState
+class _TrackedItemInputDialogState extends State<TrackedItemInputDialog> {
-    extends State<TrackedItemInputDialog> {
+  final _formKey = GlobalKey<FormState>();
-  final _expenseFormKey = GlobalKey<FormState>();
 
   int? _id;
   String _name = "";
@@ -255,12 +271,19 @@ class _TrackedItemInputDialogState
 
   @override
   Widget build(BuildContext context) {
+    if (widget.type == null &&
+        (widget.entry != null && widget.entry!.type == null)) {
+      throw FlutterError("No ItemType provided for TrackedItemInputDialog.");
+    }
+    ItemType? _type = widget.type;
+
     if (widget.entry != null) {
       _id = widget.entry!.id;
       _name = widget.entry!.name;
       _amount = widget.entry!.amount;
       widget.entry!.frequency == null ? null : _freq = widget.entry!.frequency!;
       _desc = widget.entry!.description;
+      _type = widget.entry!.type!;
     }
 
     String amountText =
@@ -276,7 +299,20 @@ class _TrackedItemInputDialogState
             onPressed: () {
               if (widget.entry != null) {
                 setState(() {
-                  DatabaseHelper.instance.addExpense(widget.entry!);
+                  switch (_type) {
+                    case ItemType.expense:
+                      DatabaseHelper.instance.addExpense(widget.entry!);
+                      break;
+                    case ItemType.income:
+                      // TODO
+                      break;
+                    case ItemType.asset:
+                      // TODO
+                      break;
+                    default:
+                      throw UnimplementedError(
+                          "Cannot add unimplemented type.");
+                  }
                   widget.notifyParent();
                 });
               }
@@ -289,7 +325,7 @@ class _TrackedItemInputDialogState
           insetPadding: EdgeInsets.all(0),
           title: Center(
             child: widget.entry == null
-                ? Text("New Expense")
+                ? Text("New ${_type!.title}")
                 : Text("Edit Expense"),
           ),
           content: FutureBuilder<List<Expense>>(
@@ -301,7 +337,7 @@ class _TrackedItemInputDialogState
                 }
                 List<Expense> expenses = snapshot.data!;
                 return Form(
-                  key: _expenseFormKey,
+                  key: _formKey,
                   child: Column(
                     mainAxisSize: MainAxisSize.min,
                     children: [
@@ -424,8 +460,8 @@ class _TrackedItemInputDialogState
             Center(
               child: ElevatedButton.icon(
                 onPressed: () {
-                  if (_expenseFormKey.currentState!.validate()) {
+                  if (_formKey.currentState!.validate()) {
-                    _expenseFormKey.currentState!.save();
+                    _formKey.currentState!.save();
                     setState(() {
                       Expense expense = Expense(
                         id: _id,