visibility toggle for undone todos

lib/widgets/todo_listtile.dart

@@ -0,0 +1,47 @@
+import 'package:flutter/material.dart';
+
+import '../models/todo.dart';
+
+class TodoListTile extends StatelessWidget {
+  const TodoListTile({super.key, required this.todo, required this.onPressed});
+  final Todo todo;
+  final VoidCallback onPressed;
+
+  @override
+  Widget build(BuildContext context) {
+    if (!todo.done) {
+      return undoneTodo(context);
+    }
+    return doneTodo(context);
+  }
+
+  Widget undoneTodo(BuildContext context) {
+    return ListTile(
+      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
+      tileColor: Theme.of(context).colorScheme.primaryContainer,
+      title: Text(todo.title),
+      trailing: IconButton(
+        onPressed: onPressed,
+        icon: Icon(
+          Icons.check_box,
+          color: Theme.of(context).colorScheme.primary,
+        ),
+      ),
+    );
+  }
+
+  Widget doneTodo(BuildContext context) {
+    return ListTile(
+      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
+      tileColor: Theme.of(context).colorScheme.surfaceVariant,
+      title: Text(todo.title),
+      trailing: IconButton(
+        onPressed: onPressed,
+        icon: Icon(
+          Icons.delete,
+          color: Theme.of(context).colorScheme.error,
+        ),
+      ),
+    );
+  }
+}