app-zj/lib/widget/gallery_photo_view_wrapper.dart

import 'dart:io';

import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:photo_view/photo_view.dart';
import 'package:photo_view/photo_view_gallery.dart';

class GalleryPhotoViewWrapper extends StatefulWidget {
  final int initialIndex;
  final PageController pageController;
  /// 相册照片
  final List<XFile>? galleryItems;
  /// 网络图片
  final List<String>? netImgList;

  GalleryPhotoViewWrapper({
    super.key,
    this.initialIndex = 0,
    this.galleryItems, this.netImgList,
  }) : pageController = PageController(initialPage: initialIndex);

  @override
  State<GalleryPhotoViewWrapper> createState() => _GalleryPhotoViewWrapperState();
}

class _GalleryPhotoViewWrapperState extends State<GalleryPhotoViewWrapper> {
  late ValueNotifier<int> indexVal = ValueNotifier(widget.initialIndex);

  PhotoViewGalleryPageOptions _buildItem(BuildContext context, int index) {
    return (widget.galleryItems ?? [] ).isNotEmpty
        ? PhotoViewGalleryPageOptions(
      imageProvider: FileImage(File(widget.galleryItems![index].path)) ,
      initialScale: PhotoViewComputedScale.contained,
      minScale: PhotoViewComputedScale.contained * (0.5 + index / 10),
      maxScale: PhotoViewComputedScale.covered * 4.1,
    )
        : PhotoViewGalleryPageOptions(
      imageProvider: CachedNetworkImageProvider(widget.netImgList![index]) ,
      initialScale: PhotoViewComputedScale.contained,
      minScale: PhotoViewComputedScale.contained * (0.5 + index / 10),
      maxScale: PhotoViewComputedScale.covered * 4.1,
    );

  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        decoration: const BoxDecoration(
          color: Colors.black,
        ),
        constraints: BoxConstraints.expand(
          height: MediaQuery.of(context).size.height,
        ),
        child: Stack(
          alignment: Alignment.bottomCenter,
          children: [
            PhotoViewGallery.builder(
              scrollPhysics: const BouncingScrollPhysics(),
              builder: _buildItem,
              itemCount:  widget.galleryItems?.length ?? widget.netImgList?.length,
              pageController: widget.pageController,
              onPageChanged: (index) {
                indexVal.value = index;
              },
            ),
            Padding(
              padding: const EdgeInsets.only(bottom: 12),
              child: ValueListenableBuilder(
                  valueListenable: indexVal,
                  builder: (context, index, child) {
                    return Text(
                      "${index + 1}/${widget.galleryItems?.length ?? widget.netImgList?.length}",
                      style: const TextStyle(
                        color: Colors.white,
                        fontSize: 18.0,
                      ),
                    );
                  }),
            ),
            Positioned(
              top: 28,
              left: 8,
              child: IconButton(
                  onPressed: () {
                    Navigator.pop(context);
                  },
                  icon: const Icon(
                    Icons.arrow_circle_left,
                    color: Colors.white,
                    size: 38,
                  )),
            ),
          ],
        ),
      ),
    );
  }
}