AppBar(
  title: Text('Flutter3-Chat'),
  flexibleSpace: Container(
    decoration: const BoxDecoration(
      gradient: LinearGradient(
        begin: Alignment.topLeft,
        end: Alignment.bottomRight,
        colors: [
          Color(0xFF0091EA), Color(0xFF07C160)
        ],
      )
    ),
  )
),

PopupMenuButton(
  icon: FStyle.iconfont(0xe62d, size: 17.0),
  offset: const Offset(0, 50.0),
  tooltip: '',
  color: const Color(0xFF353535),
  itemBuilder: (BuildContext context) {
    return <PopupMenuItem>[
      popupMenuItem(0xe666, '發起群聊', 0),
      popupMenuItem(0xe75c, '添加朋友', 1),
      popupMenuItem(0xe603, '掃一掃', 2),
      popupMenuItem(0xe6ab, '收付款', 3),
    ];
  },
  onSelected: (value) {
    switch(value) {
      case 0:
        print('發起群聊');
        break;
      case 1:
        Navigator.pushNamed(context, '/addfriends');
        break;
      case 2:
        print('掃一掃');
        break;
      case 3:
        print('收付款');
        break;
    }
  },
)

EasyRefresh(
  // 下拉加載提示
  header: const ClassicHeader(
    // showMessage: false,
  ),
  // 加載更多提示
  footer: ClassicFooter(),
  // 下拉刷新邏輯
  onRefresh: () async {
    // ...下拉邏輯
    await Future.delayed(const Duration(seconds: 2));
  },
  // 上拉加載邏輯
  onLoad: () async {
    // ...
  },
  child: ListView.builder(
    itemCount: chatList.length,
    itemBuilder: (context, index) {
      return Ink(
        // ...
      );
    },
  ),
)

// 關于彈窗
void aboutAlertDialog(BuildContext context) {
  showDialog(
    context: context,
    builder: (context) {
      return UnconstrainedBox(
        constrainedAxis: Axis.vertical,
        child: SizedBox(
          width: 320.0,
          child: AlertDialog(
            contentPadding: const EdgeInsets.symmetric(horizontal: 10.0, vertical: 20.0),
            backgroundColor: Colors.white,
            surfaceTintColor: Colors.white,
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12.0)),
            content: Padding(
              padding: const EdgeInsets.symmetric(horizontal: 10.0),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Image.asset('assets/images/logo.png', width: 90.0, height: 90.0, fit: BoxFit.cover,),
                  const SizedBox(height: 10.0),
                  const Text('Flutter3-WChat', style: TextStyle(color: Color(0xFF0091EA), fontSize: 22.0),),
                  const SizedBox(height: 5.0),
                  const Text('基于flutter3+dart3開發跨平臺仿微信App聊天實例。', style: TextStyle(color: Colors.black45),),
                  const SizedBox(height: 20.0),
                  Text('?2024/01 Andy   Q: 282310962', style: TextStyle(color: Colors.grey[400], fontSize: 12.0),),
                ],
              ),
            ),
          ),
        ),
      );
    }
  );
}

// 二維碼名片彈窗
void qrcodeAlertDialog(BuildContext context) {
  showDialog(
    context: context,
    builder: (context) {
      return UnconstrainedBox(
        constrainedAxis: Axis.vertical,
        child: SizedBox(
          width: 320.0,
          child: AlertDialog(
            contentPadding: const EdgeInsets.symmetric(horizontal: 10.0, vertical: 20.0),
            backgroundColor: const Color(0xFF07C160),
            surfaceTintColor: const Color(0xFF07C160),
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(3.0)),
            content: Padding(
              padding: const EdgeInsets.symmetric(horizontal: 10.0),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Image.asset('assets/images/qrcode.png', width: 250.0, fit: BoxFit.cover,),
                  const SizedBox(height: 15.0),
                  const Text('掃一掃，加我公眾號', style: TextStyle(color: Colors.white60, fontSize: 14.0,),),
                ],
              ),
            ),
          ),
        ),
      );
    }
  );
}

// 退出登錄彈窗
void logoutAlertDialog(BuildContext context) {
  showDialog(
    context: context,
    builder: (context) {
      return AlertDialog(
        content: const Text('確定要退出登錄嗎？', style: TextStyle(fontSize: 16.0),),
        backgroundColor: Colors.white,
        surfaceTintColor: Colors.white,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12.0)),
        elevation: 2.0,
        actionsPadding: const EdgeInsets.all(15.0),
        actions: [
          TextButton(
            onPressed: () {Navigator.of(context).pop();},
            child: const Text('取消', style: TextStyle(color: Colors.black54),)
          ),
          TextButton(
            onPressed: handleLogout,
            child: const Text('退出登錄', style: TextStyle(color: Colors.red),)
          ),
        ],
      );
    }
  );
}

ImageGroup(images: item['images'])

ImageGroup(
  images: uploadList,
  album: true,
  onChoose: () async {
    Toast.show('選擇手機相冊圖片', duration: 2, gravity: 1);
  },
)

/// 微信朋友圈九宮格圖片
library;

import 'package:flutter/material.dart';
import '../router/fade_route.dart';
import 'image_viewer.dart';

import '../utils/index.dart';

class ImageGroup extends StatelessWidget {
  const ImageGroup({
    super.key,
    this.images,
    this.width = 200.0,
    this.album = false,
    this.limit = 9,
    this.onChoose,
  });

  final List<String>? images; // 圖片組
  final double width; // 圖片寬度
  final bool album; // 是否相冊/專輯(最后面顯示+可選擇圖片)
  final int limit; // 限制多少張
  final Function? onChoose; // 選擇圖片回調

  int? get count => images?.length;
  List<String>? get imgList => count! >= limit ? images?.sublist(0, limit) : images;

  // 創建可點擊預覽圖片
  createImage(BuildContext context, String img, int key) {
    return GestureDetector(
      child: Hero(
        tag: 'image_${key}_$img', // 放大縮小動畫效果標識
        child: img == '+' ? 
        Container(color: Colors.transparent, child: const Icon(Icons.add, size: 30.0, color: Colors.black45),)
        :
        Utils.isUrl(img) ?
        Image.network(
          img,
          width: width,
          fit: BoxFit.contain,
        )
        :
        Image.asset(
          img,
          width: width,
          fit: BoxFit.contain,
        ),
      ),
      onTap: () {
        // 選擇圖片
        if(img == '+') {
          onChoose!();
        }else {
          Navigator.of(context).push(FadeRoute(route: ImageViewer(
            images: album ? imgList!.sublist(0, imgList!.length - 1) : imgList,
            index: key,
            heroTags: imgList!.asMap().entries.map((e) => 'image_${e.key}_${e.value}').toList(),
          )));
        }
      },
    );
  }

  @override
  Widget build(BuildContext context){
    // 一張圖片
    if(count == 1 && !album) {
      return SizedBox(
        width: width,
        child: createImage(context, imgList![0], 0),
      );
    }

    if(album && count! < limit) {
      imgList?.add('+');
    }
    
    // 多張圖片
    return GridView(
      shrinkWrap: true,
      physics: const NeverScrollableScrollPhysics(),
      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
        // 橫軸元素個數
        crossAxisCount: 3,
        // 縱軸間距
        mainAxisSpacing: 5.0,
        // 橫軸間距
        crossAxisSpacing: 5.0,
        // 子組件寬高比例
        childAspectRatio: 1,
      ),
      children: imgList!.asMap().entries.map((e) {
        return Container(
          color: Colors.grey[100],
          child: createImage(context, e.value, e.key),
        );
      }).toList(),
    );
  }
}

// 輸入框
Offstage(
  offstage: voiceBtnEnable,
  child: ConstrainedBox(
    constraints: BoxConstraints(maxHeight: 300.0),
    child: TextField(
      decoration: InputDecoration(
        isDense: true,
        hoverColor: Colors.transparent,
        border: OutlineInputBorder(borderSide: BorderSide.none),
        contentPadding: EdgeInsets.fromLTRB(10, 0, 10, 0)
      ),
      style: const TextStyle(fontSize: 16.0,),
      maxLines: null,
      controller: editorController,
      focusNode: editorFocusNode,
      cursorColor: const Color(0xFF07C160),
      onChanged: (value) {},
    ),
  ),
)

// 語音
Offstage(
  offstage: !voiceBtnEnable,
  child: GestureDetector(
    child: Container(
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(5),
      ),
      alignment: Alignment.center,
      height: 40.0,
      width: double.infinity,
      child: Text(voiceTypeMap[voiceType], style: const TextStyle(fontSize: 15.0),),
    ),
    onPanStart: (details) {
      setState(() {
        voiceType = 1;
        voicePanelEnable = true;
      });
    },
    onPanUpdate: (details) {
      Offset pos = details.globalPosition;
      double swipeY = MediaQuery.of(context).size.height - 120;
      double swipeX = MediaQuery.of(context).size.width / 2 + 50;
      setState(() {
        if(pos.dy >= swipeY) {
          voiceType = 1; // 松開發送
        }else if (pos.dy < swipeY && pos.dx < swipeX) {
          voiceType = 2; // 左滑松開取消
        }else if (pos.dy < swipeY && pos.dx >= swipeX) {
          voiceType = 3; // 右滑語音轉文字
        }
      });
    },
    onPanEnd: (details) {
      // print('停止錄音');
      setState(() {
        switch(voiceType) {
          case 1:
            Toast.show('發送錄音文件', duration: 1, gravity: 1);
            voicePanelEnable = false;
            break;
          case 2:
            Toast.show('取消發送', duration: 1, gravity: 1);
            voicePanelEnable = false;
            break;
          case 3:
            Toast.show('語音轉文字', duration: 1, gravity: 1);
            voicePanelEnable = true;
            voiceToTransfer = true;
            break;
        }
        voiceType = 0;
      });
    },
  ),
)

// 繪制聊天箭頭
class ArrowShape extends CustomPainter {
  ArrowShape({
    required this.arrowColor,
    this.arrowSize = 7,
  });

  final Color arrowColor; // 箭頭顏色
  final double arrowSize; // 箭頭大小

  @override
  void paint(Canvas canvas, Size size) {
    var paint = Paint()..color = arrowColor;

    var path = Path();
    path.lineTo(-arrowSize, 0);
    path.lineTo(0, arrowSize);
    path.lineTo(arrowSize, 0);
    canvas.drawPath(path, paint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return false;
  }
}