update server settings page

lib/components/number_field.dart

@@ -0,0 +1,70 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+
+class NumberFormField extends StatelessWidget {
+  const NumberFormField(
+      {Key? key,
+      this.min,
+      this.max,
+      this.initialValue,
+      this.errorMsg,
+      this.decoration,
+      this.onChanged})
+      : super(key: key);
+
+  final int? min;
+  final int? max;
+  final int? initialValue;
+  final String? errorMsg;
+  final InputDecoration? decoration;
+  final Function(int?)? onChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    final i18n = AppLocalizations.of(context)!;
+    return TextFormField(
+        initialValue: initialValue?.toString(),
+        keyboardType: TextInputType.number,
+        inputFormatters: [
+          FilteringTextInputFormatter.allow(RegExp(r"[\-0-9]")),
+        ],
+        autovalidateMode: AutovalidateMode.onUserInteraction,
+        validator: (String? value) {
+          if (value == null || value.isEmpty) {
+            return null;
+          }
+          try {
+            int v = int.parse(value);
+            if (min != null && v < min!) {
+              return errorMsg ?? i18n.numberOutOfRange;
+            }
+            if (max != null && v > max!) {
+              return errorMsg ?? i18n.numberOutOfRange;
+            }
+          } catch (e) {
+            return errorMsg ?? i18n.invalidNumber;
+          }
+          return null;
+        },
+        decoration: decoration,
+        onChanged: (String? value) {
+          if (value == null || value.isEmpty) {
+            onChanged?.call(null);
+          } else {
+            try {
+              int v = int.parse(value);
+              if (max != null && v > max!) {
+                onChanged?.call(null);
+              } else if (min != null && v < min!) {
+                onChanged?.call(null);
+              } else {
+                onChanged?.call(v);
+              }
+            } catch (e) {
+              onChanged?.call(null);
+            }
+          }
+        });
+  }
+}