tongxunruanjian/mobile/lib/widgets/search_box.dart

import 'package:flutter/material.dart';

import '../theme.dart';

/// 消息列表 / 通讯录共用的搜索框（效果图 m1/m3）：
/// 未输入时「放大镜 + 搜索」居中显示，输入后正常左对齐。
class SearchBox extends StatefulWidget {
  final ValueChanged<String> onChanged;

  const SearchBox({super.key, required this.onChanged});

  @override
  State<SearchBox> createState() => _SearchBoxState();
}

class _SearchBoxState extends State<SearchBox> {
  final TextEditingController _ctrl = TextEditingController();

  @override
  void dispose() {
    _ctrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: AppGap.x3, vertical: AppGap.x2),
      child: Stack(
        alignment: Alignment.centerLeft,
        children: [
          TextField(
            controller: _ctrl,
            onChanged: (v) {
              setState(() {});
              widget.onChanged(v.trim());
            },
            decoration: InputDecoration(
              filled: true,
              fillColor: AppColors.searchBg,
              isDense: true,
              contentPadding: const EdgeInsets.symmetric(horizontal: AppGap.x3, vertical: AppGap.x2),
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(8),
                borderSide: BorderSide.none,
              ),
            ),
          ),
          // 空内容时的居中占位（不拦截点击，点按穿透到输入框）
          if (_ctrl.text.isEmpty)
            const IgnorePointer(
              child: Center(
                child: Row(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Icon(Icons.search, size: 20, color: AppColors.textSecondary),
                    SizedBox(width: AppGap.x1),
                    Text('搜索', style: TextStyle(fontSize: AppFont.sub, color: AppColors.textSecondary)),
                  ],
                ),
              ),
            ),
        ],
      ),
    );
  }
}