fixed lint problems

lib/main.dart

@@ -10,6 +10,6 @@ class MyApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(title: _title, home: MyHomePage());
+    return const MaterialApp(title: _title, home: MyHomePage());
   }
 }

lib/pages/main_page.dart

@@ -9,17 +9,17 @@ class MyHomePage extends StatefulWidget {
   const MyHomePage({super.key});
 
   @override
-  _MyHomePageState createState() => _MyHomePageState();
+  MyHomePageState createState() => MyHomePageState();
 }
 
-class _MyHomePageState extends State<MyHomePage> {
+class MyHomePageState extends State<MyHomePage> {
   int _selectedIndex = 2;
-  static final List<Widget> _widgetOptions = <Widget>[
-    const MoodPage(),
-    const SleepPage(),
+  static const List<Widget> _widgetOptions = <Widget>[
+    MoodPage(),
+    SleepPage(),
     StopWatchTimerPage(),
-    const RelapsePage(),
-    const SettingsPage(),
+    RelapsePage(),
+    SettingsPage(),
   ];
 
   void _onItemTapped(int index) {

lib/pages/timer_page.dart

@@ -3,34 +3,29 @@ import 'package:flutter/material.dart';
 import 'package:smoke_cess_app/widgets/timer_button.dart';
 
 class StopWatchTimerPage extends StatefulWidget {
+  const StopWatchTimerPage({super.key});
+
   @override
-  _StopWatchTimerPageState createState() => _StopWatchTimerPageState();
+  StopWatchTimerPageState createState() => StopWatchTimerPageState();
 }
 
-class _StopWatchTimerPageState extends State<StopWatchTimerPage> {
+class StopWatchTimerPageState extends State<StopWatchTimerPage> {
   static const countdownDuration = Duration(minutes: 1);
-  Duration duration = Duration();
+  Duration duration = countdownDuration;
   Timer? timer;
 
   bool countDown = true;
 
-  @override
-  void initState() {
-    // TODO: implement initState
-    super.initState();
-    reset();
-  }
-
   void reset() {
     if (countDown) {
       setState(() => duration = countdownDuration);
     } else {
-      setState(() => duration = Duration());
+      setState(() => duration = const Duration());
     }
   }
 
   void startTimer() {
-    timer = Timer.periodic(Duration(seconds: 1), (_) => addTime());
+    timer = Timer.periodic(const Duration(seconds: 1), (_) => addTime());
   }
 
   void addTime() {
@@ -58,7 +53,7 @@ class _StopWatchTimerPageState extends State<StopWatchTimerPage> {
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
             buildTime(),
-            SizedBox(
+            const SizedBox(
               height: 80,
             ),
             buildButtons()
@@ -71,11 +66,11 @@ class _StopWatchTimerPageState extends State<StopWatchTimerPage> {
     final minutes = twoDigits(duration.inMinutes.remainder(60));
     final seconds = twoDigits(duration.inSeconds.remainder(60));
     return Row(mainAxisAlignment: MainAxisAlignment.center, children: [
-      SizedBox(
+      const SizedBox(
         width: 8,
       ),
       buildTimeCard(time: minutes, header: 'MINUTEN'),
-      SizedBox(
+      const SizedBox(
         width: 8,
       ),
       buildTimeCard(time: seconds, header: 'SEKUNDEN'),
@@ -87,21 +82,21 @@ class _StopWatchTimerPageState extends State<StopWatchTimerPage> {
         mainAxisAlignment: MainAxisAlignment.center,
         children: [
           Container(
-            padding: EdgeInsets.all(8),
+            padding: const EdgeInsets.all(8),
             decoration: BoxDecoration(
                 color: Colors.white, borderRadius: BorderRadius.circular(20)),
             child: Text(
               time,
-              style: TextStyle(
+              style: const TextStyle(
                   fontWeight: FontWeight.bold,
                   color: Colors.black,
                   fontSize: 50),
             ),
           ),
-          SizedBox(
+          const SizedBox(
             height: 24,
           ),
-          Text(header, style: TextStyle(color: Colors.black45)),
+          Text(header, style: const TextStyle(color: Colors.black45)),
         ],
       );
 
@@ -111,7 +106,7 @@ class _StopWatchTimerPageState extends State<StopWatchTimerPage> {
     return isRunning || isCompleted
         ? TimerButton(
             onClicked: stopTimer,
-            icon: Icon(
+            icon: const Icon(
               Icons.stop,
               size: 50,
               color: Colors.white,
@@ -119,7 +114,7 @@ class _StopWatchTimerPageState extends State<StopWatchTimerPage> {
             color: Colors.red)
         : TimerButton(
             onClicked: startTimer,
-            icon: Icon(
+            icon: const Icon(
               Icons.play_arrow,
               size: 50,
               color: Colors.white,

lib/widgets/timer_button.dart

@@ -12,16 +12,17 @@ class TimerButton extends StatelessWidget {
       required this.color})
       : super(key: key);
 
+  @override
   Widget build(BuildContext context) {
     return Column(
       children: [
         InkWell(
+          onTap: onClicked,
           child: CircleAvatar(
             backgroundColor: color,
             radius: 50,
             child: icon,
           ),
-          onTap: onClicked,
         ),
       ],
     );