Refactor codebase resolving warnings and remove self-package imports

lib/view/pages/more/countdown/addTimerDialog.dart

@@ -0,0 +1,59 @@
+
+import 'package:flutter/material.dart';
+
+class AddTimerDialog extends StatefulWidget {
+  const AddTimerDialog({Key? key}) : super(key: key);
+
+  @override
+  State<AddTimerDialog> createState() => _AddTimerDialogState();
+}
+
+class _AddTimerDialogState extends State<AddTimerDialog> {
+  DateTime selected = DateTime.now().add(const Duration(days: 1));
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const Text("Timer hinzufügen"),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          const TextField(
+            decoration: InputDecoration(
+              labelText: "Timer Name"
+            ),
+          ),
+
+          TextButton(onPressed: () async {
+            DateTime? selectedDate = await showDatePicker(context: context, initialDate: DateTime.now(), firstDate: DateTime.now(), lastDate: DateTime.now().add(const Duration(days: 365 * 10)));
+            if(selectedDate == null) return;
+
+            setState(() {
+              selected = selectedDate;
+            });
+
+          }, child: const Text("Datum auswählen")),
+
+          TextButton(onPressed: () async {
+            TimeOfDay? selectedTime = await showTimePicker(context: context, initialTime: TimeOfDay.fromDateTime(DateTime.now()));
+            if(selectedTime == null) return;
+
+            setState(() {
+              selected = selected.copyWith(hour: selectedTime.hour, minute: selectedTime.minute);
+            });
+          }, child: const Text("Zeit auswählen")),
+
+          Text(selected.toString())
+        ],
+      ),
+      actions: [
+        TextButton(onPressed: () {
+          Navigator.of(context).pop();
+        }, child: const Text("Abbrechen")),
+        TextButton(onPressed: () {
+          // TODO add timer
+        }, child: const Text("Hinzufügen")),
+      ],
+    );
+  }
+}