mobileCyberGamesApp/lib/pages/AppNotice.dart

import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:wanna_battle/net/HttpManager.dart';

Future getAppNotice(context) async {
  final res = await HttpManager.get('systemVariable/getOne', data: {
    'variableName': 'appNotice',
  });
  if (res.success) {
    final String imageUrl = (res.data ?? {})['variableValue'] ?? '';
    if (imageUrl.isNotEmpty) {
      return showGeneralDialog(
        context: context,
        barrierDismissible: true,
        pageBuilder: (BuildContext buildContext, Animation<double> animation, Animation<double> secondaryAnimation) {
          return AppNotice(
            pics: ((res.data ?? {})['variableValue'] ?? '').split(','),
          );
        },
        barrierLabel: MaterialLocalizations.of(context).modalBarrierDismissLabel,
        barrierColor: Colors.black87,
        transitionDuration: const Duration(milliseconds: 300),
      );
    }
  }
}

class AppNotice extends StatefulWidget {
  final List<String> pics;

  const AppNotice({Key key, this.pics}) : super(key: key);

  @override
  State<StatefulWidget> createState() {
    return AppNoticeState();
  }
}

class AppNoticeState extends State<AppNotice> {
  final pageController = PageController(initialPage: 0);
  int currPage = 0;

  @override
  Widget build(BuildContext context) {
    widget.pics.forEach((f) {
      precacheImage(Image.network(f).image, context);
    });
    return Material(
      color: Colors.transparent,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        mainAxisSize: MainAxisSize.min,
        children: <Widget>[
          SizedBox(
            width: double.infinity,
            height: (MediaQuery.of(context).size.width - 56) * 420 / 348,
            child: PageView(
              controller: pageController,
              onPageChanged: (page) {
                setState(() {
                  currPage = page;
                });
              },
              children: widget.pics.map<Widget>((f) {
                return Container(
                  height: (MediaQuery.of(context).size.width - 56) * 420 / 348,
                  margin: EdgeInsets.only(left: 28, right: 28),
                  child: SizedBox(
                    child: ClipRRect(
                      borderRadius: BorderRadius.circular(4),
                      child: CachedNetworkImage(
                        imageUrl: f,
                        fit: BoxFit.cover,
                      ),
                    ),
                  ),
                );
              }).toList(),
            ),
          ),
          Container(
            margin: EdgeInsets.only(top: 20),
            child: GestureDetector(
              child: Image.asset(currPage == widget.pics.length - 1 ? 'images/icon_guanbi.png' : 'images/icon_next_page.png'),
              onTap: () {
                if (currPage == widget.pics.length - 1) {
                  Navigator.of(context).pop();
                } else {
                  pageController.nextPage(duration: Duration(milliseconds: 500), curve: Curves.linearToEaseOut);
                }
              },
            ),
          )
        ],
      ),
    );
  }
}