Break code into multiple files.

android/app/build.gradle

@@ -6,7 +6,7 @@ plugins {
 }
 
 android {
-    namespace = "com.example.flutter_empty"
+    namespace = "com.hyperling.expense_tracker"
     compileSdk = flutter.compileSdkVersion
     ndkVersion = flutter.ndkVersion
 
@@ -21,7 +21,7 @@ android {
 
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
-        applicationId = "com.example.flutter_empty"
+        applicationId = "com.hyperling.expense_tracker"
         // You can update the following values to match your application needs.
         // For more information, see: https://flutter.dev/to/review-gradle-config.
         minSdk = flutter.minSdkVersion

android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <application
-        android:label="flutter_empty"
+        android:label="Recurring Expense Tracker"
         android:name="${applicationName}"
         android:icon="@mipmap/ic_launcher">
         <activity

lib/main.dart

@@ -3,98 +3,128 @@
 
 import 'package:flutter/material.dart';
 
+import '/pages/expense.dart';
+import '/pages/income.dart';
+import '/pages/asset.dart';
+import '/pages/report.dart';
+import '/pages/settings.dart';
+
 void main() {
   runApp(const MainApp());
 }
 
-class MainApp extends StatefulWidget {
+class MainApp extends StatelessWidget {
   const MainApp({super.key});
 
-  @override
-  State<MainApp> createState() => _MainAppState();
-}
-
-class _MainAppState extends State<MainApp> {
-  final nameFieldController = TextEditingController();
-
-  @override
-  void dispose() {
-    // Clean up the controller when the widget is disposed.
-    nameFieldController.dispose();
-    super.dispose();
-  }
-
   @override
   Widget build(BuildContext context) {
-    const inputWidth = 400.0;
-    const inputHeight = 50.0;
-
-    const recurrenceValues = <DropdownMenuEntry>[
-      DropdownMenuEntry(value: Recurrence.daily, label: "Daily"),
-      DropdownMenuEntry(value: Recurrence.weekly, label: "Weekly"),
-      DropdownMenuEntry(value: Recurrence.biweekly, label: "Biweekly"),
-      DropdownMenuEntry(value: Recurrence.montly, label: "Monthly"),
-      DropdownMenuEntry(value: Recurrence.yearly, label: "Yearly"),
-    ];
-
-    return const MaterialApp(
-      home: Scaffold(
-        body: Center(
-          child: Column(mainAxisSize: MainAxisSize.min, spacing: 10, children: [
-            Text('Input an expense below!'),
-            SizedBox(
-                width: inputWidth,
-                height: inputHeight,
-                child: TextField(
-                  keyboardType: TextInputType.text,
-                  decoration: InputDecoration(
-                    labelText: "Name",
-                    hintText: "Example: Red Pocket Phone Bill",
-                  ),
-                  // https://docs.flutter.dev/cookbook/forms/retrieve-input
-                  //controller: nameFieldController,
-                )),
-            SizedBox(
-              width: inputWidth,
-              height: inputHeight,
-              child: TextField(
-                keyboardType: TextInputType.numberWithOptions(decimal: true),
-                decoration: InputDecoration(
-                    labelText: "Cost", hintText: "Example: 10.00"),
-              ),
-            ),
-            DropdownMenu(
-              dropdownMenuEntries: recurrenceValues,
-              width: inputWidth,
-              label: Text("Recurrence"),
-              hintText: "Example: Monthly",
-            ),
-            SizedBox(
-                width: inputWidth,
-                height: inputHeight,
-                child: TextField(
-                  keyboardType: TextInputType.text,
-                  decoration: InputDecoration(
-                      labelText: "Description",
-                      hintText:
-                          "Example: 1GB data with unlimited talk & text."
-                    ),
-                )),
-          ]),
-        ),
+    return MaterialApp(
+      title: 'Recurring Expense Tracker',
+      theme: ThemeData(
+        useMaterial3: true,
+        colorScheme: ColorScheme.fromSeed(seedColor: Colors.green),
       ),
+      home: HomePage(),
     );
   }
 }
 
-// https://www.tutorialspoint.com/dart_programming/dart_programming_enumeration.htm
-enum Recurrence { daily, weekly, biweekly, montly, yearly }
+class HomePage extends StatefulWidget {
+  const HomePage({
+    super.key,
+  });
 
-class Expense {
-  String name;
-  double cost;
-  Recurrence recurrence;
-  String description;
-
-  Expense(this.name, this.cost, this.recurrence, this.description);
+  @override
+  State<HomePage> createState() => _HomePageState();
+}
+
+class _HomePageState extends State<HomePage> {
+  var pageSelected = 0;
+
+  @override
+  Widget build(BuildContext context) {
+    Widget page;
+    Widget? dialog;
+    switch (pageSelected) {
+      case 0:
+        page = ExpensePage();
+        dialog = ExpenseInputDialog();
+      case 1:
+        page = IncomePage();
+      case 2:
+        page = AssetPage();
+      case 3:
+        page = ProjectionPage();
+      case 4:
+        page = SettingsPage();
+      default:
+        throw UnimplementedError('No widget for page $pageSelected yet!');
+    }
+
+    Future<void> addNewValue(BuildContext context) {
+      return showDialog(
+          context: context, builder: (_) => AlertDialog(content: dialog));
+    }
+
+    Widget? floatingButton;
+    if (dialog != null) {
+      floatingButton = IconButton(
+        onPressed: () {
+          addNewValue(context);
+        },
+        icon: Icon(Icons.add),
+        color: Theme.of(context).colorScheme.onSurface,
+      );
+    }
+
+    return LayoutBuilder(builder: (context, constraints) {
+      return Scaffold(
+        // TODO: Add a drawer instead of nav rail.
+        body: Row(
+          children: [
+            SafeArea(
+              child: NavigationRail(
+                extended: constraints.maxWidth >= 800,
+                destinations: [
+                  NavigationRailDestination(
+                    icon: Icon(Icons.payment),
+                    label: Text('Expenses'),
+                  ),
+                  NavigationRailDestination(
+                    icon: Icon(Icons.account_balance),
+                    label: Text('Income'),
+                  ),
+                  NavigationRailDestination(
+                    icon: Icon(Icons.attach_money),
+                    label: Text('Liquid Assets'),
+                  ),
+                  NavigationRailDestination(
+                    icon: Icon(Icons.bar_chart),
+                    label: Text('Projections'),
+                  ),
+                  NavigationRailDestination(
+                    icon: Icon(Icons.settings),
+                    label: Text('Settings'),
+                  ),
+                ],
+                selectedIndex: pageSelected,
+                onDestinationSelected: (value) {
+                  setState(() {
+                    pageSelected = value;
+                  });
+                },
+              ),
+            ),
+            Expanded(
+              child: Container(
+                color: Theme.of(context).colorScheme.primaryContainer,
+                child: page,
+              ),
+            ),
+          ],
+        ),
+        floatingActionButton: floatingButton,
+      );
+    });
+  }
 }

lib/models/expense.dart

@@ -0,0 +1,18 @@
+import '/models/frequency.dart';
+
+class Expense {
+  final String name;
+  final double cost;
+  final Frequency frequency;
+  final String description;
+
+  const Expense(
+      {required this.name,
+      required this.cost,
+      required this.frequency,
+      required this.description});
+
+  String toString() {
+    return "$name, $cost, ${frequency.title}, $description";
+  }
+}

lib/models/frequency.dart

@@ -0,0 +1,12 @@
+// https://www.tutorialspoint.com/dart_programming/dart_programming_enumeration.htm
+enum Frequency {
+  daily(title: "Daily"),
+  weekly(title: "Weekly"),
+  biweekly(title: "Biweekly"),
+  montly(title: "Monthly"),
+  yearly(title: "Yearly");
+
+  const Frequency({required this.title});
+
+  final String title;
+}

lib/pages/asset.dart

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

lib/pages/expense.dart

@@ -0,0 +1,214 @@
+import 'package:flutter/material.dart';
+
+import '/models/expense.dart';
+import '/models/frequency.dart';
+
+List<Expense> expenses = [];
+
+class ExpensePage extends StatelessWidget {
+  const ExpensePage({
+    super.key,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return ListView.builder(
+        itemCount: expenses.length,
+        itemBuilder: (_, index) {
+          final Expense curr = expenses[index];
+          return Center(
+            child: Padding(
+              padding: const EdgeInsets.all(4.0),
+              child: Container(
+                decoration: BoxDecoration(
+                  borderRadius: BorderRadius.circular(4),
+                  color: Colors.greenAccent,
+                ),
+                child: Column(
+                  children: [
+                    Text(curr.name),
+                    Text("${curr.cost.toString()} ${curr.frequency.title}"),
+                  ],
+                ),
+              ),
+            ),
+          );
+        });
+    /*
+    return ListView(
+      children: [
+        ListTile(
+          title: Text("Fake Item 1"),
+          subtitle: Text("30.00 / month"),
+        ),
+        ListTile(
+          title: Text("Fake Item 2"),
+          subtitle: Text("180.00 / year"),
+        ),
+      ],
+    );
+    */
+  }
+}
+
+class ExpenseInputDialog extends StatefulWidget {
+  const ExpenseInputDialog({
+    super.key,
+  });
+
+  @override
+  State<ExpenseInputDialog> createState() => _ExpenseInputDialogState();
+}
+
+class _ExpenseInputDialogState extends State<ExpenseInputDialog> {
+  final _expenseFormKey = GlobalKey<FormState>();
+
+  String _name = "";
+  double _cost = 0.0;
+  Frequency _freq = Frequency.montly;
+  String _desc = "";
+
+  @override
+  Widget build(BuildContext context) {
+    const inputWidth = 300.0;
+    const inputHeight = 50.0;
+
+    List<DropdownMenuItem> freqValues = [];
+    for (var freq in Frequency.values) {
+      freqValues.add(DropdownMenuItem(value: freq, child: Text(freq.title)));
+    }
+    ;
+
+    return AlertDialog(
+      title: Center(child: Text("Add New Expense")),
+      content: Form(
+        key: _expenseFormKey,
+        autovalidateMode: AutovalidateMode.onUserInteraction,
+        child: Column(mainAxisSize: MainAxisSize.min, spacing: 10, children: [
+          SizedBox(
+            width: inputWidth,
+            height: inputHeight,
+            child: TextFormField(
+              keyboardType: TextInputType.text,
+              decoration: InputDecoration(
+                labelText: "Name",
+                hintText: "Example: Red Pocket Phone Bill",
+              ),
+              validator: (value) {
+                if (value!.isEmpty) {
+                  return "Name must be provided.";
+                }
+                return null;
+              },
+              onSaved: (newValue) {
+                _name = newValue!;
+              },
+            ),
+          ),
+          SizedBox(
+            width: inputWidth,
+            height: inputHeight,
+            child: TextFormField(
+              keyboardType: TextInputType.numberWithOptions(decimal: true),
+              decoration: InputDecoration(
+                  labelText: "Cost", hintText: "Example: 10.00"),
+              validator: (value) {
+                if (value!.isEmpty) {
+                  return "Cost must be provided.";
+                }
+                if (double.tryParse(value) == null) {
+                  return "Cost must be a valid number.";
+                }
+                return null;
+              },
+              onSaved: (newValue) {
+                _cost = double.parse(newValue!);
+              },
+            ),
+          ),
+          SizedBox(
+            width: inputWidth,
+            height: inputHeight,
+            child: DropdownButtonFormField(
+              items: freqValues,
+              decoration: InputDecoration(
+                  labelText: "Recurrence", hintText: "Example: Monthly"),
+              validator: (value) {
+                if (value == null) {
+                  return "Frequency must be provided.";
+                }
+                if (!Frequency.values.contains(value)) {
+                  return "Value not valid.";
+                }
+                return null;
+              },
+              onChanged: (newValue) {
+                _freq = newValue;
+              },
+            ),
+          ),
+          SizedBox(
+            width: inputWidth,
+            height: inputHeight,
+            child: TextFormField(
+              keyboardType: TextInputType.text,
+              decoration: InputDecoration(
+                  labelText: "Description",
+                  hintText: "Example: 1GB data with unlimited talk & text."),
+              validator: (value) {
+                return null;
+              },
+              onSaved: (newValue) {
+                _desc = newValue!;
+              },
+            ),
+          ),
+        ]),
+      ),
+      actions: [
+        SizedBox(
+          width: inputWidth,
+          height: inputHeight,
+          child: Row(
+            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+            crossAxisAlignment: CrossAxisAlignment.center,
+            children: [
+              ElevatedButton.icon(
+                onPressed: () {
+                  print("TODO: Clear fields!");
+                  Navigator.of(context).pop();
+                },
+                icon: Icon(Icons.cancel),
+                label: Text('Cancel'),
+              ),
+              ElevatedButton.icon(
+                onPressed: () {
+                  print("TODO: Save expense!");
+                  if (_expenseFormKey.currentState!.validate()) {
+                    _expenseFormKey.currentState!.save();
+                    setState(() {
+                      expenses.add(
+                        Expense(
+                            name: _name,
+                            cost: _cost,
+                            frequency: _freq,
+                            description: _desc),
+                      );
+                    });
+                    print(expenses.toString());
+                    for (var expense in expenses) {
+                      print(expense.toString());
+                    }
+                    Navigator.of(context).pop();
+                  }
+                },
+                icon: Icon(Icons.save),
+                label: Text('Submit'),
+              ),
+            ],
+          ),
+        )
+      ],
+    );
+  }
+}

lib/pages/income.dart

@@ -0,0 +1,18 @@
+import 'package:flutter/material.dart';
+
+class IncomePage extends StatelessWidget {
+  const IncomePage({
+    super.key,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+        child: Column(
+      children: [
+        Text("TBD"),
+        Placeholder(),
+      ],
+    ));
+  }
+}

lib/pages/report.dart

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

lib/pages/settings.dart

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

linux/CMakeLists.txt

@@ -4,10 +4,10 @@ project(runner LANGUAGES CXX)
 
 # The name of the executable created for the application. Change this to change
 # the on-disk name of your application.
-set(BINARY_NAME "flutter_empty")
+set(BINARY_NAME "expense_tracker")
 # The unique GTK application identifier for this application. See:
 # https://wiki.gnome.org/HowDoI/ChooseApplicationID
-set(APPLICATION_ID "com.example.flutter_empty")
+set(APPLICATION_ID "com.hyperling.expense_tracker")
 
 # Explicitly opt in to modern CMake behaviors to avoid warnings with recent
 # versions of CMake.

linux/runner/my_application.cc

@@ -40,11 +40,11 @@ static void my_application_activate(GApplication* application) {
   if (use_header_bar) {
     GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
     gtk_widget_show(GTK_WIDGET(header_bar));
-    gtk_header_bar_set_title(header_bar, "flutter_empty");
+    gtk_header_bar_set_title(header_bar, "Recurring Expense Tracker");
     gtk_header_bar_set_show_close_button(header_bar, TRUE);
     gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
   } else {
-    gtk_window_set_title(window, "flutter_empty");
+    gtk_window_set_title(window, "Recurring Expense Tracker");
   }
 
   gtk_window_set_default_size(window, 1280, 720);

pubspec.yaml

@@ -1,5 +1,5 @@
-name: flutter_empty
-description: "A new Flutter project."
+name: flutter_expense_tracker
+description: Track recurring expenses against income and liquid assets.
 publish_to: 'none'
 version: 0.1.0
 

run_offline.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+flutter run --no-pub