improve: 设置页面样式改进

- 下拉选择改为dialog, 参考 Android 系统内部设置关于选项的行为
- 一些列表对齐问题
- 字体设置预览文字居中

lib/pages/setting/widgets/select_dialog.dart

@@ -0,0 +1,68 @@
+import 'package:flutter/material.dart';
+import 'package:pilipala/models/common/theme_type.dart';
+
+class SelectDialog<T> extends StatefulWidget {
+  final T value;
+  final String title;
+  final List<dynamic> values;
+  const SelectDialog({super.key, required this.value, required this.values, required this.title});
+
+  @override
+  _SelectDialogState<T> createState() => _SelectDialogState<T>();
+}
+
+class _SelectDialogState<T> extends State<SelectDialog<T>> {
+
+  late T _tempValue;
+
+  @override
+  void initState() {
+    super.initState();
+    _tempValue = widget.value;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    TextStyle titleStyle = Theme.of(context).textTheme.titleMedium!;
+
+    return AlertDialog(
+      title: Text(widget.title),
+      contentPadding: const EdgeInsets.fromLTRB(0, 12, 0, 12),
+      content: StatefulBuilder(
+          builder: (context, StateSetter setState) {
+            return SingleChildScrollView(
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  for (var i in widget.values) ...[
+                    RadioListTile(
+                      value: i['value'],
+                      title: Text(i['title'], style: titleStyle),
+                      groupValue: _tempValue,
+                      onChanged: (value) {
+                        print(value);
+                        setState(() {
+                          _tempValue = value as T;
+                        });
+                      },
+                    ),
+                  ]
+                ],
+              ),
+            );
+          }),
+      actions: [
+        TextButton(
+            onPressed: () => Navigator.pop(context),
+            child: Text(
+              '取消',
+              style: TextStyle(
+                  color: Theme.of(context).colorScheme.outline),
+            )),
+        TextButton(
+            onPressed: () => Navigator.pop(context, _tempValue),
+            child: const Text('确定'))
+      ],
+    );
+  }
+}