Fixed Android issues

lib/widgets/error_widget.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:get/get.dart';
+
+class CustomErrorWidget extends StatelessWidget {
+  final String errorMessage;
+  final VoidCallback onRetry;
+
+  const CustomErrorWidget({
+    Key? key,
+    required this.errorMessage,
+    required this.onRetry,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: [
+          const Text(
+            'エラーが発生しました',
+            style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
+          ),
+          const SizedBox(height: 8),
+          Text(errorMessage),
+          const SizedBox(height: 16),
+          ElevatedButton(
+            onPressed: onRetry,
+            child: const Text('再試行'),
+          ),
+        ],
+      ),
+    );
+  }
+}